TransDigm (TDG) 10-Q 4 May 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	6 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	TDG
Entity Registrant Name	TRANSDIGM GROUP INC
Entity Central Index Key	1,260,221
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		52,430,416

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 1,011,007	$ 650,561
Trade accounts receivable - Net	644,985	636,127
Inventories - Net	767,232	730,681
Assets held-for-sale	0	77,500
Prepaid expenses and other	46,880	38,683
Total current assets	2,470,104	2,133,552
PROPERTY, PLANT AND EQUIPMENT - NET	352,456	324,924
GOODWILL	5,758,705	5,745,338
OTHER INTANGIBLE ASSETS - NET	1,700,409	1,717,862
OTHER	113,003	53,985
TOTAL ASSETS	10,394,677	9,975,661
CURRENT LIABILITIES:
Current portion of long-term debt	69,147	69,454
Short-term borrowings - trade receivable securitization facility	299,833	299,587
Accounts payable	151,709	148,761
Accrued liabilities	292,146	335,888
Liabilities held-for-sale	0	17,304
Total current liabilities	812,835	870,994
LONG-TERM DEBT	11,365,790	11,393,620
DEFERRED INCOME TAXES	359,342	500,949
OTHER NON-CURRENT LIABILITIES	166,047	161,302
Total liabilities	12,704,014	12,926,865
STOCKHOLDERS’ DEFICIT:
Common stock - $.01 par value; authorized 224,400,000 shares; issued 56,513,989 and 56,093,659 at March 31, 2018 and September 30, 2017, respectively	565	561
Additional paid-in capital	1,143,715	1,095,319
Accumulated deficit	(2,684,832)	(3,187,220)
Accumulated other comprehensive income (loss)	6,519	(85,143)
Treasury stock, at cost; 4,161,326 and 4,159,207 shares at March 31, 2018 and September 30, 2017, respectively	(775,304)	(774,721)
Total stockholders’ deficit	(2,309,337)	(2,951,204)
TOTAL LIABILITIES AND STOCKHOLDERS’ DEFICIT	$ 10,394,677	$ 9,975,661

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets Parenthetical - $ / shares	Mar. 31, 2018	Sep. 30, 2017
Statement of Financial Position [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	224,400,000	224,400,000
Common Stock, Shares, Issued	56,513,989	56,093,659
Treasury Stock, Shares	4,161,326	4,159,207

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
NET SALES	$ 933,070	$ 868,728	$ 1,781,030	$ 1,682,746
COST OF SALES	398,996	379,291	770,306	749,054
GROSS PROFIT	534,074	489,437	1,010,724	933,692
SELLING AND ADMINISTRATIVE EXPENSES	107,526	100,857	214,054	202,572
AMORTIZATION OF INTANGIBLE ASSETS	17,457	22,032	34,569	47,563
INCOME FROM OPERATIONS	409,091	366,548	762,101	683,557
INTEREST EXPENSE - NET	161,266	147,842	322,199	293,846
REFINANCING COSTS	638	3,507	1,751	35,591
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	247,187	215,199	438,151	354,120
INCOME TAX PROVISION	45,347	59,508	(75,700)	79,558
INCOME FROM CONTINUING OPERATIONS	201,840	155,691	513,851	274,562
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(5,562)	(186)	(2,798)	(186)
NET INCOME	196,278	155,505	511,053	274,376
NET INCOME APPLICABLE TO COMMON STOCK	$ 196,278	$ 155,505	$ 454,905	$ 178,405
Net earnings per share:
Net earnings per share from continuing operations--basic and diluted	$ 3.63	$ 2.78	$ 8.23	$ 3.17
Net loss per share from discontinued operations--basic and diluted	(0.10)	0	(0.05)	0
Net earnings per share	3.53	2.78	8.18	3.17
Cash dividends paid per common share	$ 0	$ 0	$ 0	$ 24
Weighted-average shares outstanding:
Basic and diluted (in shares)	55,605	55,894	55,599	56,211

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Net income	$ 196,278	$ 155,505	$ 511,053	$ 274,376
Other comprehensive income, net of tax:
Foreign currency translation adjustments	23,036	8,050	28,188	(20,002)
Interest rate swap and cap agreements	45,226	2,179	63,474	40,954
Other comprehensive income, net of tax	68,262	10,229	91,662	20,952
TOTAL COMPREHENSIVE INCOME	$ 264,540	$ 165,734	$ 602,715	$ 295,328

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Changes in Stockholders' Deficit - 6 months ended Mar. 31, 2018 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income	Treasury Stock
BALANCE (in shares) at Sep. 30, 2017	56,093,659	56,093,659
BALANCE (in shares) at Sep. 30, 2017	(4,159,207)					(4,159,207)
BALANCE at Sep. 30, 2017	$ (2,951,204)	$ 561	$ 1,095,319	$ (3,187,220)	$ (85,143)	$ (774,721)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unvested dividend equivalents and other	(8,665)			(8,665)
Compensation expense recognized for employee stock options and restricted stock	21,942		21,942
Exercise of employee stock options, restricted stock activity and other, net (in shares)		419,825				2,119
Exercise of employee stock options, restricted stock activity and other, net	25,726	$ 4	26,305			$ 583
Common stock issued (in shares)		505
Common stock issued	149		149
Net income	511,053			511,053
Foreign currency translation adjustments	28,188				28,188
Interest rate swaps and caps, net of tax	$ 63,474				63,474
BALANCE (in shares) at Mar. 31, 2018	56,513,989	56,513,989
BALANCE (in shares) at Mar. 31, 2018	(4,161,326)					(4,161,326)
BALANCE at Mar. 31, 2018	$ (2,309,337)	$ 565	$ 1,143,715	$ (2,684,832)	$ 6,519	$ (775,304)

Condensed Consolidated Stateme7

Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
OPERATING ACTIVITIES:
Net income	$ 511,053	$ 274,376
Net loss from discontinued operations	2,798	186
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	26,727	24,733
Amortization of intangible assets and product certification costs	34,882	47,975
Amortization of debt issuance costs, original issue discount and premium	10,594	10,170
Refinancing costs	1,751	35,591
Non-cash equity compensation	22,703	21,126
Deferred income taxes	(166,592)	346
Changes in assets/liabilities, net of effects from acquisitions of businesses:
Trade accounts receivable	5,864	3,108
Inventories	(16,337)	6,896
Income taxes receivable/payable	26,648	23,706
Other assets	(8,803)	(4,151)
Accounts payable	(624)	(17,545)
Accrued interest	883	(822)
Accrued and other liabilities	2,137	(35,195)
Net cash provided by operating activities	453,684	390,500
INVESTING ACTIVITIES:
Capital expenditures	(30,884)	(38,436)
Payments made in connection with acquisitions	(50,320)	(30,002)
Proceeds (payments made) from sale (purchase) of discontinued operations	57,686	(78,879)
Net cash used in investing activities	(23,518)	(147,317)
FINANCING ACTIVITIES:
Proceeds from exercise of stock options	26,305	12,345
Special dividend and dividend equivalent payments	(56,148)	(1,375,998)
Treasury stock purchased	0	339,833
Proceeds from term loans, net	793,042	1,132,774
Repayment on term loans	(833,052)	(32,302)
Cash tender and redemption of senior subordinated notes due 2021, including premium	0	(528,847)
Proceeds from additional senior subordinated notes due 2025, net	0	301,006
Other	(2,155)	(10,745)
Net cash used in financing activities	(72,008)	(841,600)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	2,288	(3,188)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	360,446	(601,605)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	650,561	1,586,994
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,011,007	985,389
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid during the period for interest	310,949	289,311
Cash paid during the period for income taxes	$ 56,606	$ 55,544

DESCRIPTION OF THE BUSINESS

DESCRIPTION OF THE BUSINESS	6 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
DESCRIPTION OF THE BUSINESS	DESCRIPTION OF THE BUSINESS Description of the Business – TransDigm Group Incorporated (“TD Group”), through its wholly-owned subsidiary, TransDigm Inc., is a leading global designer, producer and supplier of highly engineered aircraft components for use on nearly every commercial and military aircraft in service today. TransDigm Inc., along with TransDigm Inc.’s direct and indirect wholly-owned operating subsidiaries (collectively, with TD Group, the “Company” or “TransDigm”), offers a broad range of proprietary aerospace components. TD Group has no significant assets or operations other than its 100% ownership of TransDigm Inc. TD Group’s common stock is listed on the New York Stock Exchange, or the NYSE, under the trading symbol “TDG.” Major product offerings, substantially all of which are ultimately provided to end-users in the aerospace industry, include mechanical/electro-mechanical actuators and controls, ignition systems and engine technology, specialized pumps and valves, power conditioning devices, specialized AC/DC electric motors and generators, NiCad batteries and chargers, engineered latching and locking devices, rods and locking devices, engineered connectors and elastomers, databus and power controls, cockpit security components and systems, specialized cockpit displays, aircraft audio systems, specialized lavatory components, seat belts and safety restraints, engineered interior surfaces and related components, lighting and control technology, military personnel parachutes, high performance hoists, winches and lifting devices, and cargo loading, handling and delivery systems.

UNAUDITED INTERIM FINANCIAL INF

UNAUDITED INTERIM FINANCIAL INFORMATION	6 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
UNAUDITED INTERIM FINANCIAL INFOMRATION	UNAUDITED INTERIM FINANCIAL INFORMATION The financial information included herein is unaudited; however, the information reflects all adjustments (consisting of normal recurring adjustments) that are, in the opinion of management, necessary for a fair presentation of the Company’s financial position and results of operations and cash flows for the interim periods presented. These financial statements and notes should be read in conjunction with the financial statements and related notes for the year ended September 30, 2017 included in TD Group’s Form 10-K filed on November 13, 2017. As disclosed therein, the Company’s annual consolidated financial statements were prepared in conformity with generally accepted accounting principles in the United States (“GAAP”). The September 30, 2017 condensed consolidated balance sheet was derived from TD Group’s audited financial statements. The results of operations for the twenty-six week period ended March 31, 2018 are not necessarily indicative of the results to be expected for the full year. Certain reclassifications have been made to the prior year financial statements to conform to current year presentation related to the designation of Schroth as discontinued operations beginning in the fourth quarter of fiscal 2017 (refer to Note 14, "Discontinued Operations," for further information) and an organizational realignment effective October 1, 2017 of certain businesses comprising the Power & Control and the Non-Aviation segments.

ACQUISITIONS

ACQUISITIONS	6 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS AND DIVESTITURES During the twenty-six week period ended March 31, 2018, the Company completed the acquisition of the Kirkhill elastomers business ("Kirkhill") from Esterline Technologies. During the fiscal year ended September 30, 2017 , the Company completed the acquisitions of three separate aerospace product lines (collectively, the "Third Quarter 2017 Acquisitions"). The Company accounted for the acquisitions using the acquisition method and included the results of operations of the acquisitions in its condensed consolidated financial statements from the effective date of each acquisition. As of March 31, 2018 , the one-year measurement period is open for Kirkhill and the Third Quarter 2017 Acquisitions; therefore, the assets acquired and liabilities assumed related to these acquisitions are subject to adjustment until the end of their respective one-year measurement periods. Pro forma net sales and results of operations for the acquisitions had they occurred at the beginning of the applicable twenty-six week period ended March 31, 2018 or April 1, 2017 are not material and, accordingly, are not provided. The acquisitions strengthen and expand the Company’s position to design, produce and supply highly engineered proprietary aerospace components in niche markets with significant aftermarket content and provide opportunities to create value through the application of our three core value-driven operating strategies (obtaining profitable new business, improving our cost structure, and providing highly engineered value-added products to customers). The purchase price paid for each acquisition reflects the current earnings before interest, taxes, depreciation and amortization (EBITDA) and cash flows, as well as the future EBITDA and cash flows expected to be generated by the business, which are driven in most cases by the recurring aftermarket consumption over the life of a particular aircraft, estimated to be approximately 25 to 30 years . Kirkhill – On March 15, 2018, the Company acquired the assets and certain liabilities of the Kirkhill elastomers business from Esterline Technologies for a total purchase price of approximately $50 million in cash subject to purchase price adjustments. Kirkhill's products are primarily proprietary, sole source with significant aftermarket content and used in a broad variety of most major commercial transport and military platforms. Kirkhill is also well represented on newer commercial platforms such as Boeing’s 787, 777X and 737MAX; Airbus’s A320NEO and A350; as well as the military JSF. Kirkhill is included in TransDigm's Airframe segment. The Company expects that no goodwill recognized for the acquisition will be deductible for tax purposes. Third Quarter 2017 Acquisitions – The Third Quarter 2017 Acquisitions were acquired for an aggregate purchase price of approximately $106.7 million in cash, which includes working capital settlements totaling $1.0 million paid in the third and fourth quarters of 2017 and an earn-out of $0.4 million paid in the second quarter of 2018. All three product lines consist primarily of proprietary, sole source products with significant aftermarket content. The products include highly engineered aerospace controls, quick disconnect couplings, and communication electronics. Each product line acquired was consolidated into an existing TransDigm reporting unit within TransDigm's Power & Control segment. The Company expects that approximately $66 million of goodwill recognized for the acquisitions will be deductible for tax purposes over 15 years and approximately $9 million of goodwill recognized for the acquisitions will not be deductible for tax purposes. Schroth – On February 22, 2017, the Company acquired all of the outstanding stock of Schroth Safety Products GmbH and certain aviation and defense assets and liabilities from subsidiaries of Takata Corporation (collectively, "Schroth"), for a total purchase price of approximately $89.7 million , which consisted primarily of $79.7 million paid in cash during fiscal 2017 and an approximately $9.0 million indemnity holdback, of which $8.5 million was paid in April 2018. In connection with the settlement of a Department of Justice investigation into the competitive effects of the acquisition, during the fourth quarter of 2017, the Company committed to dispose of the Schroth business. Therefore, Schroth was classified as held-for-sale beginning in the fourth quarter of 2017. The results of operations of Schroth are reflected as discontinued operations in the accompanying condensed consolidated financial statements. On January 26, 2018, the Company completed the sale of Schroth in a management buyout to a private equity fund and certain members of Schroth management for approximately $61.4 million , subject to a working capital adjustment. Further disclosure related to Schroth’s discontinued operations is included in Note 14.

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	6 Months Ended
	Mar. 31, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, which created a new topic in the Accounting Standards Codification (“ASC”) 606, “Revenue From Contracts With Customers .” In addition to superseding and replacing nearly all existing U.S. GAAP revenue recognition guidance, including industry-specific guidance, ASC 606 establishes a new control-based revenue recognition model. The new revenue standards may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. The guidance is effective for the Company for annual reporting periods, including interim periods therein, beginning October 1, 2018, which is the Company’s planned date of adoption. The Company expects to use the modified retrospective method. The Company is continuing to evaluate the impact of the standard. For each reporting unit, we have evaluated a representative sample of contracts and other agreements with our customers and evaluated the provisions contained within these contracts and agreements in consideration of the five step model specified within ASC 606. We are in the process of documenting the impact of the standard on our current accounting policies and practices in order to identify material differences, if any, that would result from applying the new requirements to our revenue contracts. We continue to make progress on our assessment of ASC 606 and are also in the process of evaluating the impact, if any, on changes to our business processes, systems, and controls to support recognition and disclosure requirements under ASC 606. In February 2016, the FASB issued ASU 2016-02, “Leases (ASC 842),” which will require that a lessee recognize assets and liabilities on the balance sheet for all leases with a lease term of more than twelve months, with the result being the recognition of a right of use asset and a lease liability. The guidance is effective for the Company for annual reporting periods, including interim periods therein, beginning October 1, 2019, with early adoption permitted. The Company is currently evaluating the impact of adopting this standard on its consolidated financial statements and disclosures. In June 2016, the FASB issued ASU 2016-13, "Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (ASU 2016-13)," which changes the impairment model for most financial assets. The new model uses a forward-looking expected loss method, which will generally result in earlier recognition of allowances for losses. ASU 2016-13 is effective for annual and interim periods beginning after December 15, 2019 and early adoption is permitted for annual and interim periods beginning after December 15, 2018. The Company is currently evaluating the impact of adopting this standard on its consolidated financial statements and disclosures. In August 2016, the FASB issued ASU 2016-15, "Statement of Cash Flows—Classification of Certain Cash Receipts and Cash Payments," which clarifies existing guidance related to accounting for cash receipts and cash payments and classification on the statement of cash flows. This guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted. The Company elected to early adopt this standard in the fourth quarter of fiscal 2017. The adoption of this standard did not have a material impact on its consolidated statement of cash flows. In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment,” to eliminate Step 2 from the goodwill impairment test in order to simplify the subsequent measurement of goodwill. The guidance is effective for fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this standard is not expected to have a material impact on its consolidated financial statements and disclosures. In March 2017, the FASB issued ASU 2017-07, "Compensation—Retirement Benefits (ASC 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost," that will change how employers that sponsor defined benefit and/or other postretirement benefit plans present the net periodic benefit cost in the income statement. Under the new guidance, employers will present the service cost component of the net periodic benefit cost in the same income statement line item(s) as other employee compensation costs arising from services rendered during the period. In addition, only the service cost component will be eligible for capitalization in assets. Employers will present the other components separately from the line item(s) that includes the service cost and outside of any subtotal of operating income, if one is presented. Employers will have to disclose the line(s) used to present the other components of net periodic benefit cost, if the components are not presented separately in the income statement.The standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within the fiscal year. Early adoption is permitted, including adoption in any interim period for which financial statements have not yet been issued. The adoption of this standard is not expected to have a material impact on our consolidated financial statements. In May 2017, the FASB issued ASU 2017-09, "Compensation—Stock Compensation (ASC 718): Scope of Modification Accounting," which provides clarity on which changes to the terms or conditions of share-based payment awards require an entity to apply the modification accounting provisions required in ASC 718. The standard is effective for all entities for annual periods beginning after December 15, 2017, with early adoption permitted, including adoption in any interim period for which financial statements have not yet been issued. The adoption of this standard is not expected to have a material impact on our consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging (ASC 815): Targeted Improvements to Accounting for Hedging Activities,” which amends the FASB’s hedge accounting model to enable entities to better portray their risk management activities in financial statements. The guidance eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance also eases certain documentation and assessment requirements and modifies the accounting for components excluded from the assessment of hedge effectiveness. ASU 2017-12 is effective for the Company for annual reporting periods, including interim periods therein, beginning October 1, 2018, with early adoption permitted. As early adoption is permissible, the Company adopted the pronouncement beginning October 1, 2017. Changes were applied prospectively in accordance with the standard and prior periods were not adjusted. The adoption of this standard did not have a material impact on our consolidated financial statements and disclosures. In February 2018, the FASB issued ASU 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income," which gives entities the option to reclassify tax effects stranded in accumulated other comprehensive income as a result of the Tax Cuts and Jobs Act (the "Act") into retained earnings. The guidance allows entities to reclassify from accumulated other comprehensive income to retained earnings stranded tax effects resulting from the Act's new federal corporate income tax rate. The guidance also allows entities to elect to reclassify other stranded tax effects that relate to the Act but do not directly relate to the change in the federal tax rate (e.g., state taxes, changing from a worldwide tax system to a territorial system). Tax effects that are stranded in accumulated other comprehensive income for other reasons (e.g., prior changes in tax law, a change in valuation allowance) may not be reclassified. The standard is effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within the fiscal year. Early adoption is permitted, including adoption in any interim period for which financial statements have not yet been issued. Entities have the option to apply the guidance retrospectively or in the period of adoption. The adoption of this standard is not expected to have a material impact on our consolidated financial statements. In March 2018, the FASB issued ASU 2018-05, “Income Taxes (Topic 740), Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118.” The ASU adds various SEC paragraphs pursuant to the issuance of the December 2017 SEC Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”), which was effective immediately. The SEC issued SAB 118 to address concerns about reporting entities’ ability to timely comply with the accounting requirements to recognize all of the effects of the Tax Cuts and Jobs Act in the period of enactment. SAB 118 allows disclosure that timely determination of some or all of the income tax effects from the Tax Cuts and Jobs Act are incomplete by the due date of the financial statements and if possible to provide a reasonable estimate. We have accounted for the tax effects of the Tax Cuts and Jobs Act under the guidance of SAB 118, on a provisional basis. Our accounting for certain income tax effects is incomplete, but we have determined reasonable estimates for those effects and have recorded provisional amounts in our condensed consolidated financial statements. Refer to Note 9, "Income Taxes," for further information.

EARNINGS PER SHARE (TWO-CLASS M

EARNINGS PER SHARE (TWO-CLASS METHOD)	6 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
EARNINGS PER SHARE (TWO-CLASS METHOD)	EARNINGS PER SHARE (TWO-CLASS METHOD) The following table sets forth the computation of basic and diluted earnings per share (in thousands, except per share data): Thirteen Week Periods Ended Twenty-Six Week Periods Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 Numerator for earnings per share: Net income from continuing operations $ 201,840 $ 155,691 $ 513,851 $ 274,562 Less dividends paid on participating securities — — (56,148 ) (95,971 ) $ 201,840 $ 155,691 $ 457,703 $ 178,591 Net loss from discontinued operations (5,562 ) (186 ) (2,798 ) (186 ) Net income applicable to common stock - basic and diluted $ 196,278 $ 155,505 $ 454,905 $ 178,405 Denominator for basic and diluted earnings per share under the two-class method: Weighted average common shares outstanding 52,229 52,849 52,127 53,108 Vested options deemed participating securities 3,376 3,045 3,472 3,103 Total shares for basic and diluted earnings per share 55,605 55,894 55,599 56,211 Net earnings per share from continuing operations - basic and diluted $ 3.63 $ 2.78 $ 8.23 $ 3.17 Net loss per share from discontinued operations - basic and diluted $ (0.10 ) $ — (0.05 ) — Net earnings per share $ 3.53 $ 2.78 $ 8.18 $ 3.17

INVENTORIES

INVENTORIES	6 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES Inventories are stated at the lower of cost or market. Cost of inventories is generally determined by the average cost and the first-in, first-out (FIFO) methods and includes material, labor and overhead related to the manufacturing process. Inventories consist of the following (in thousands): March 31, 2018 September 30, 2017 Raw materials and purchased component parts $ 517,910 $ 496,899 Work-in-progress 204,940 187,009 Finished goods 134,762 131,548 Total 857,612 815,456 Reserves for excess and obsolete inventory (90,380 ) (84,775 ) Inventories - Net $ 767,232 $ 730,681

INTANGIBLE ASSETS

INTANGIBLE ASSETS	6 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	INTANGIBLE ASSETS Other intangible assets - net in the condensed consolidated balance sheets consist of the following (in thousands): March 31, 2018 September 30, 2017 Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net Trademarks and trade names $ 742,028 $ — $ 742,028 $ 729,931 $ — $ 729,931 Technology 1,292,753 383,509 909,244 1,292,719 351,638 941,081 Order backlog 8,700 2,252 6,448 29,000 26,668 2,332 Other 63,382 20,693 42,689 63,599 19,081 44,518 Total $ 2,106,863 $ 406,454 $ 1,700,409 $ 2,115,249 $ 397,387 $ 1,717,862 Intangible assets acquired during the twenty-six week period ended March 31, 2018 were as follows (in thousands): Gross Amount Amortization Period Intangible assets not subject to amortization: Goodwill $ 2,218 Trademarks and trade names 10,000 12,218 Intangible assets subject to amortization: Technology 2,000 20 years Order backlog 6,000 1 year 8,000 5.8 years Total $ 20,218 The aggregate amortization expense on identifiable intangible assets for the twenty-six week period s ended March 31, 2018 and April 1, 2017 was approximately $34.6 million and $47.6 million , respectively. The estimated amortization expense is $71.9 million for fiscal year 2018 , $70.2 million for fiscal year 2019 , and $67.2 million for each of the four succeeding fiscal years 2020 through 2023 . The following is a summary of changes in the carrying value of goodwill by segment from September 30, 2017 through March 31, 2018 (in thousands): Power & Control Airframe Non- aviation Total Balance - September 30, 2017 $ 3,269,981 $ 2,382,082 $ 93,275 $ 5,745,338 Goodwill acquired during the year — 2,218 — 2,218 Purchase price allocation adjustments 4,508 — — 4,508 Currency translation adjustment — 6,645 — 6,645 Other (191 ) 187 — (4 ) Balance - March 31, 2018 $ 3,274,298 $ 2,391,132 $ 93,275 $ 5,758,705

DEBT

DEBT	6 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
DEBT	DEBT The Company’s debt consists of the following (in thousands): March 31, 2018 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 300,000 $ (167 ) $ — $ 299,833 Term loans $ 6,938,145 $ (60,435 ) $ (18,221 ) $ 6,859,489 5 1/2% senior subordinated notes due 2020 (2020 Notes) 550,000 (2,715 ) — 547,285 6% senior subordinated notes due 2022 (2022 Notes) 1,150,000 (6,221 ) — 1,143,779 6 1/2% senior subordinated notes due 2024 (2024 Notes) 1,200,000 (7,454 ) — 1,192,546 6 1/2% senior subordinated notes due 2025 (2025 Notes) 750,000 (3,769 ) 3,909 750,140 6 3/8% senior subordinated notes due 2026 (2026 Notes) 950,000 (8,302 ) — 941,698 11,538,145 (88,896 ) (14,312 ) 11,434,937 Less current portion 69,685 (538 ) — 69,147 Long-term debt $ 11,468,460 $ (88,358 ) $ (14,312 ) $ 11,365,790 September 30, 2017 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 300,000 $ (413 ) $ — $ 299,587 Term loans $ 6,973,009 $ (64,104 ) $ (18,948 ) $ 6,889,957 2020 Notes 550,000 (3,243 ) — 546,757 2022 Notes 1,150,000 (6,941 ) — 1,143,059 2024 Notes 1,200,000 (8,042 ) — 1,191,958 2025 Notes 750,000 (4,033 ) 4,182 750,149 2026 Notes 950,000 (8,806 ) — 941,194 11,573,009 (95,169 ) (14,766 ) 11,463,074 Less current portion 70,031 (577 ) — 69,454 Long-term debt $ 11,502,978 $ (94,592 ) $ (14,766 ) $ 11,393,620 Accrued interest was $83.1 million and $82.2 million as of March 31, 2018 and September 30, 2017, respectively. Amendment No.4 to the Second Amended and Restated Credit Agreement - On November 30, 2017, the Company entered into Amendment No. 4 to the Second Amended and Restated Credit Agreement. Pursuant to Amendment No. 4, TransDigm, among other things, converted approximately $798 million of existing tranche D term loans into additional tranche F term loans and decreased the margin applicable to the existing tranche E term loans and tranche F term loans to LIBO rate plus 2.75% per annum. The terms and conditions (other than maturity date) that apply to the tranche F term loans, including pricing, are substantially the same as the terms and conditions that apply to the tranche D term loans immediately prior to Amendment No. 4. The Company capitalized $2.9 million and expensed $0.7 million of refinancing costs representing debt issuance costs associated with Amendment No. 4 during the twenty-six week period ended March 31, 2018 . Additionally, the Company wrote off $0.5 million in unamortized debt issuance costs related to the tranche D term loans that were converted to tranche F term loans and wrote off $0.2 million in unamortized debt issuance costs related to the tranche F terms loans. Refinancing Facility Agreement to the Second Amended and Restated Credit Agreement - On February 22, 2018, the Company entered into a refinancing facility agreement. TransDigm, among other things, incurred new tranche G term loans in an aggregate principal amount equal to $1,809 million and repaid in full all of the existing tranche G term loans outstanding under the Second and Amended Restated Credit Agreement immediately prior to the refinancing facility agreement. The refinancing facility agreement also decreased the margin applicable to the tranche G term loans to LIBO rate plus 2.5% per annum. The terms and conditions that apply to the tranche G term loans, including pricing, are substantially the same as the terms and conditions that apply to the tranche G term loans immediately prior to the refinancing facility agreement. The Company capitalized $0.5 million and expensed $0.2 million of refinancing costs representing debt issuance costs associated with the refinancing facility agreement during the twenty-six week period ended March 31, 2018 . Additionally, the Company wrote off $0.2 million in unamortized debt issuance costs related to the tranche G terms loans.

INCOME TAXES

INCOME TAXES	6 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Tax Cuts and Jobs Act (the "Act") was enacted on December 22, 2017. The Act reduces the U.S. federal corporate tax rate from 35% to 21% , requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign-sourced earnings. The rate change is administratively effective at the beginning of our fiscal year (October 1, 2017), using a blended rate for the annual period. As a result, the blended statutory tax rate for the year is 24.5% . At March 31, 2018, we had not completed our accounting for the tax effects of enactment of the Act; however, in certain cases, we have made a reasonable estimate of the effects on our existing deferred tax balances and the one-time transition tax. We have recognized a provisional benefit amount of $170.2 million related to the remeasurement of our deferred tax balance for the twenty-six week period ended March 31, 2018. However, we are still analyzing certain aspects of the Act and refining our calculations, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. In addition, we have recognized a provisional expense amount of $23.1 million for our one-time transition tax liability for the twenty-six week period ended March 31, 2018. The one-time transition tax is based on our total post-1986 earnings and profits ("E&P") that we previously deferred from U.S. income taxes and is based in part on the amount of those earnings held in cash and other specified assets. However, we continue to refine the calculation of the total post-1986 E&P for our foreign subsidiaries. This amount may change when we finalize the calculation of post-1986 foreign E&P previously deferred from US federal taxation and finalize the amounts held in cash or other specified assets. As a result of the Act, we recognized a net provisional benefit amount of $147.1 million as a discrete tax benefit, which is included as a component of income tax expense from continuing operations for the twenty-six week period ended March 31, 2018. At the end of each reporting period, TD Group makes an estimate of its annual effective income tax rate. The estimate used in the year-to-date period may change in subsequent periods. During the thirteen week periods ended March 31, 2018 and April 1, 2017 , the effective income tax rate was 18.3% and 27.7% , respectively. During the twenty-six week period s ended March 31, 2018 and April 1, 2017 , the effective income tax rate was (17.3)% and 22.5% , respectively. The Company's lower effective tax rate for the thirteen week ended March 31, 2018 was primarily due to the reduction in the U.S. federal corporate statutory rate related to the enactment of the Act. The Company’s lower effective tax rate for the twenty-six week period ended March 31, 2018 was primarily due to the reduction in the U.S. federal corporate tax rate as well as discrete adjustments related to the enactment of the Act described above. The Company’s effective tax rate for the thirteen and twenty-six week periods ended March 31, 2018 was lower than the Federal statutory tax rate primarily due to enactment of the Act described above. The Company’s effective tax rate for the thirteen and twenty-six periods ended April 1, 2017 was lower than the Federal statutory tax rate primarily due to excess tax benefits from share based payments, the domestic manufacturing deduction and foreign earnings taxed at rates lower than the U.S. statutory rate. The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction, various state and local jurisdictions as well as foreign jurisdictions located in Belgium, Canada, China, France, Germany, Hong Kong, Hungary, Japan, Malaysia, Mexico, Norway, Singapore, Sri Lanka, Sweden and the United Kingdom. The Company is no longer subject to U.S. federal examinations for years before fiscal 2014. The Company is currently under U.S. federal examination for fiscal 2014. In addition, the Company is subject to state income tax examinations for fiscal years 2009 and later. At March 31, 2018 and September 30, 2017 , TD Group had $8.8 million and $8.7 million in unrecognized tax benefits, the recognition of which would have an effect of approximately $8.7 million on the effective tax rate at March 31, 2018 and September 30, 2017 , respectively. The Company believes the tax positions that comprise the unrecognized tax benefits will be reduced by approximately $0.6 million over the next 12 months. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in income tax expense.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The following table presents our assets and liabilities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy. The fair value hierarchy has three levels based on the reliability of the inputs used to determine fair value. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly. Level 3 inputs are unobservable inputs for the asset or liability. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The following summarizes the carrying amounts and fair values of financial instruments (in thousands): March 31, 2018 September 30, 2017 Level Carrying Amount Fair Value Carrying Amount Fair Value Assets: Cash and cash equivalents 1 $ 1,011,007 $ 1,011,007 $ 650,561 $ 650,561 Interest rate cap agreements (1) 2 27,343 27,343 12,904 12,904 Interest rate swap agreements (2) 2 2,507 2,507 — — Interest rate swap agreements (1) 2 41,719 41,719 2,905 2,905 Liabilities: Interest rate swap agreements (3) 2 1,533 1,533 20,740 20,740 Interest rate swap agreements (4) 2 54 54 9,731 9,731 Short-term borrowings - trade receivable securitization facility (5) 1 299,833 299,833 299,587 299,587 Long-term debt, including current portion: Term loans (5) 2 6,859,489 6,935,358 6,889,957 6,965,628 2020 Notes (5) 1 547,285 552,750 546,757 558,250 2022 Notes (5) 1 1,143,779 1,173,000 1,143,059 1,178,750 2024 Notes (5) 1 1,192,546 1,230,000 1,191,958 1,236,000 2025 Notes (5) 1 750,140 765,218 750,149 776,807 2026 Notes (5) 1 941,698 954,750 941,194 971,375 (1) Included in other non-current assets on the condensed consolidated balance sheet. (2) Included in prepaid expenses and other on the condensed consolidated balance sheet. (3) Included in accrued liabilities on the condensed consolidated balance sheet. (4) Included in other non-current liabilities on the condensed consolidated balance sheet. (5) The carrying amount of the debt instrument is presented net of the debt issuance costs. Refer to Note 8, "Debt," for gross carrying amounts. The Company values its financial instruments using an industry standard market approach, in which prices and other relevant information are generated by market transactions involving identical or comparable assets or liabilities. No financial instruments were recognized using unobservable inputs. Interest rate swaps were measured at fair value using quoted market prices for the swap interest rate indexes over the term of the swap discounted to present value versus the fixed rate of the contract. The interest rate caps were measured at fair value using implied volatility rates of each individual caplet and the yield curve for the related periods. The estimated fair value of the Company’s term loans was based on information provided by the agent under the Company’s senior secured credit facility. The estimated fair values of the Company’s notes were based upon quoted market prices. There has not been any impact to the fair value of derivative liabilities due to the Company's own credit risk. Similarly, there has not been any impact to the fair value of derivative assets based on the Company's evaluation of counterparties' credit risks. The fair value of cash and cash equivalents, trade accounts receivable-net and accounts payable approximated book value due to the short-term nature of these instruments at March 31, 2018 and September 30, 2017 .

DERIVATIVES AND HEDGING ACTIVIT

DERIVATIVES AND HEDGING ACTIVITIES	6 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES AND HEDGING ACTIVITIES	DERIVATIVES AND HEDGING ACTIVITIES The Company is exposed to, among other things, the impact of changes in interest rates in the normal course of business. The Company’s risk management program is designed to manage the exposure and volatility arising from these risks, and utilizes derivative financial instruments to offset a portion of these risks. The Company uses derivative financial instruments only to the extent necessary to hedge identified business risks and does not enter into such transactions for trading purposes. The Company generally does not require collateral or other security with counterparties to these financial instruments and is therefore subject to credit risk in the event of nonperformance; however, the Company monitors credit risk and currently does not anticipate nonperformance by other parties. The Company has agreements with each of its swap and cap counterparties that contain a provision whereby if the Company defaults on the credit facility the Company could also be declared in default on its swaps and caps, resulting in an acceleration of payment under the swaps and caps. Interest rate swap and cap agreements are used to manage interest rate risk associated with floating-rate borrowings under our credit facility. The interest rate swap and cap agreements utilized by the Company effectively modify the Company’s exposure to interest rate risk by converting a portion of the Company’s floating-rate debt to a fixed rate basis through the expiration date of the interest rate swap and cap agreements, thereby reducing the impact of interest rate changes on future interest expense. These agreements involve the receipt of floating rate amounts in exchange for fixed rate interest payments over the term of the agreements without an exchange of the underlying principal amount. These derivative instruments qualify as effective cash flow hedges under GAAP. For these cash flow hedges, the effective portion of the gain or loss from the financial instruments was initially reported as a component of accumulated other comprehensive loss in stockholders’ deficit and subsequently reclassified into earnings in the same line as the hedged item in the same period or periods during which the hedged item affected earnings. As the interest rate swap and cap agreements are used to manage interest rate risk, any gains or losses from the derivative instruments that are reclassified into earnings are recognized in interest expense - net in the condensed consolidated statements of income. The following table summarizes the Company's interest rate swap agreements: Aggregate Notional Amount (in millions) Start Date End Date Related Term Loans Conversion of Related Variable Rate Debt to Fixed Rate of: $1,000 9/30/2014 6/30/2019 Tranche G 4.90% (2.40% plus the 2.50% margin percentage) $400 9/30/2017 9/30/2022 Tranche G 4.40% (1.90% plus the 2.50% margin percentage) $750 6/30/2020 6/30/2022 Tranche F 5.25% (2.50% plus the 2.75% margin percentage) $500 12/30/2016 12/31/2021 Tranche F 4.65% (1.90% plus the 2.75% margin percentage) $1,000 6/28/2019 6/30/2021 Tranche F 4.55% (1.80% plus the 2.75% margin percentage) $750 3/31/2016 6/30/2020 Tranche F 5.55% (2.80% plus the 2.75% margin percentage) The following table summarizes the Company's interest rate cap agreements: Aggregate Notional Amount Start Date End Date Related Term Loans Offsets Variable Rate Debt Attributable to Fluctuations Above: $750 6/30/2020 6/30/2022 Tranche F Three month LIBO rate of 2.50% $400 12/30/2016 12/31/2021 Tranche F Three month LIBO rate of 2.50% $400 6/30/2016 6/30/2021 Tranche F Three month LIBO rate of 2.00% $750 9/30/2015 6/30/2020 Tranche E Three month LIBO rate of 2.50% All interest rate swap and cap agreements are recognized in our condensed consolidated balance sheets at fair value. Certain derivative asset and liability balances are offset where master netting agreements provide for the legal right of setoff. For classification purposes, we record the net fair value of each type of derivative position that is expected to settle in less than one year with each counterparty as a net current asset or liability and each type of long-term position as a net long-term asset or liability. The amounts shown in the table below represent the gross amounts of recognized assets and liabilities, the amounts offset in the condensed consolidated balance sheet and the net amounts of assets and liabilities presented therein. March 31, 2018 September 30, 2017 Asset Liability Asset Liability Interest rate cap agreements $ 27,343 $ — $ 12,904 $ — Interest rate swap agreements 46,604 (3,965 ) 9,235 (36,801 ) Total 73,947 (3,965 ) 22,139 (36,801 ) Effect of counterparty netting (2,378 ) 2,378 (6,330 ) 6,330 Net derivatives as classified in the balance sheet (1) $ 71,569 $ (1,587 ) $ 15,809 $ (30,471 ) (1) Refer to Note 10, "Fair Value Measurements," for the condensed consolidated balance sheet classification of our interest rate swap and cap agreements. Based on the fair value amounts of the interest rate swap and cap agreements determined as of March 31, 2018 , the estimated net amount of existing gains and losses and caplet amortization expected to be reclassified into interest expense within the next twelve months is approximately $2.1 million . Effective September 30, 2016, the Company redesignated the interest rate cap agreements related to the $400 million and the $750 million aggregate notional amount with cap rates of 2.0% and 2.5% , respectively, based on the expected probable cash flows associated with the 2016 term loans and 2015 term loans in consideration of the Company’s ability to select one-month, two-month, three-month, or six-month LIBO rate set forth in the Second Amended and Restated Credit Agreement. Accordingly, amounts previously recorded as a component of accumulated other comprehensive loss in stockholder’s deficit amortized into interest expense was $2.0 million and $1.9 million for the twenty-six week period s ended March 31, 2018 and April 1, 2017, respectively. The accumulated other comprehensive loss to be reclassified into interest expense over the remaining term of the cap agreements is $8.9 million with a related tax benefit of $2.4 million as of March 31, 2018 . Effective December 30, 2017, the Company redesignated the existing interest rate swap agreements related to the $750 million , $500 million , $1,000 million and $750 million aggregate notional amounts with swap rates of 5.25% , 4.65% , 4.55% and 5.55% , respectively, based on the expected probable cash flows associated with the tranche F term loans in consideration of the Company’s removal of the LIBO rate floor on the tranche F term loans as set forth in Amendment No. 4 to the Second Amended and Restated Credit Agreement. Accordingly, the amount recorded as a component of accumulated other comprehensive loss in stockholders’ deficit related to these redesignated interest rate swap hedges will be amortized into earnings based on the original maturity date of the related interest rate swap agreements. Accordingly, amounts previously recorded as a component of accumulated other comprehensive loss in stockholder’s deficit amortized into interest expense was $0.3 million for the twenty-six week period ended March 31, 2018 . The accumulated other comprehensive gain to be reclassified into interest expense over the remaining term of the swap agreements is immaterial. Effective March 31, 2018, the Company redesignated the existing interest rate swap agreements related to the $1,000 million and the $400 million aggregate notional amount with swap rates of 4.90% and 4.40% , respectively, based on the expected probable cash flows associated with the tranche G term loans in consideration of the Company’s removal of the LIBO rate floor on the tranche G term loans as set forth in the refinancing facility agreement dated February 22, 2018 related to the Second Amended and Restated Credit Agreement. Accordingly, the amount recorded as a component of accumulated other comprehensive loss in stockholders’ deficit related to these redesignated interest rate swap hedges of approximately $12.8 million with a related tax expense of $3.1 million as of March 31, 2018 , will be amortized into earnings based on the original maturity date of the related interest rate swap agreements.

SEGMENTS

SEGMENTS	6 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
SEGMENTS	SEGMENTS The Company’s businesses are organized and managed in three reporting segments: Power & Control, Airframe and Non-aviation. The Power & Control segment includes operations that primarily develop, produce and market systems and components that predominately provide power to or control power of the aircraft utilizing electronic, fluid, power and mechanical motion control technologies. Major product offerings include mechanical/electro-mechanical actuators and controls, ignition systems and engine technology, specialized pumps and valves, power conditioning devices, specialized AC/DC electric motors and generators, databus and power controls, high performance hoists, winches and lifting devices and cargo loading and handling systems. Primary customers of this segment are engine and power system and subsystem suppliers, airlines, third party maintenance suppliers, military buying agencies and repair depots. Products are sold in the original equipment and aftermarket market channels. The Airframe segment includes operations that primarily develop, produce and market systems and components that are used in non-power airframe applications utilizing airframe and cabin structure technologies. Major product offerings include engineered latching and locking devices, rods and locking devices, engineered connectors and elastomers, cockpit security components and systems, aircraft audio systems, specialized lavatory components, seat belts and safety restraints, engineered interior surfaces and related components, lighting and control technology, military personnel parachutes and cargo delivery systems. Primary customers of this segment are airframe manufacturers and cabin system suppliers and subsystem suppliers, airlines, third party maintenance suppliers, military buying agencies and repair depots. Products are sold in the original equipment and aftermarket market channels. The Non-aviation segment includes operations that primarily develop, produce and market products for non-aviation markets. Major product offerings include seat belts and safety restraints for ground transportation applications, mechanical/electro-mechanical actuators and controls for space applications, refueling systems for heavy equipment used in mining, construction and other industries and turbine controls for the energy and oil and gas markets. Primary customers of this segment are off-road vehicle suppliers and subsystem suppliers, child restraint system suppliers, satellite and space system suppliers, manufacturers of heavy equipment used in mining, construction and other industries and turbine original equipment manufacturers, gas pipeline builders and electric utilities. The primary measurement used by management to review and assess the operating performance of each segment is EBITDA As Defined. The Company defines EBITDA As Defined as earnings before interest, taxes, depreciation and amortization plus certain non-operating items recorded as corporate expenses including refinancing costs, acquisition-related costs, transaction-related costs and non-cash compensation charges incurred in connection with the Company’s stock option plans. Acquisition-related costs represent accounting adjustments to inventory associated with acquisitions of businesses and product lines that were charged to cost of sales when the inventory was sold; costs incurred to integrate acquired businesses and product lines into the Company’s operations, facility relocation costs and other acquisition-related costs; transaction related costs comprising deal fees; legal, financial and tax diligence expenses and valuation costs that are required to be expensed as incurred and other acquisition accounting adjustments. EBITDA As Defined is not a measurement of financial performance under GAAP. Although the Company uses EBITDA As Defined to assess the performance of its business and for various other purposes, the use of this non-GAAP financial measure as an analytical tool has limitations, and it should not be considered in isolation or as a substitute for analysis of the Company’s results of operations as reported in accordance with GAAP. The Company’s segments are reported on the same basis used internally for evaluating performance and for allocating resources. The accounting policies for each segment are the same as those described in the summary of significant accounting policies in the Company’s consolidated financial statements. Intersegment sales and transfers are recorded at values based on market prices, which creates intercompany profit on intersegment sales or transfers that is eliminated in consolidation. Intersegment sales were insignificant for the periods presented below. Certain corporate-level expenses are allocated to the operating segments. Effective October 1, 2017, the Company made an organizational realignment of certain businesses comprising the Power & Control, Airframe and the Non-Aviation segments. Operating results for the thirteen and twenty-six week period s ended April 1, 2017 and total assets as of September 30, 2017 were reclassified to conform to the presentation for the thirteen and twenty-six week period s ended March 31, 2018 . The following table presents net sales by reportable segment (in thousands): Thirteen Week Periods Ended Twenty-Six Week Periods Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 Net sales to external customers Power & Control $ 528,460 $ 473,952 $ 1,011,178 $ 909,784 Airframe 369,783 360,509 703,175 709,173 Non-aviation 34,827 34,267 66,677 63,789 $ 933,070 $ 868,728 $ 1,781,030 $ 1,682,746 The following table reconciles EBITDA As Defined by segment to consolidated income from continuing operations before income taxes (in thousands): Thirteen Week Periods Ended Twenty-Six Week Periods Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 EBITDA As Defined Power & Control $ 275,562 $ 232,828 $ 520,337 $ 445,746 Airframe 186,006 182,980 344,425 351,509 Non-aviation 10,321 11,391 19,317 20,668 Total segment EBITDA As Defined 471,889 427,199 884,079 817,923 Unallocated corporate expenses 8,766 5,523 19,423 15,053 Total Company EBITDA As Defined 463,123 421,676 864,656 802,870 Depreciation and amortization expense 30,970 34,661 61,609 72,708 Interest expense - net 161,266 147,842 322,199 293,846 Acquisition-related costs 4,485 7,752 6,559 26,320 Stock compensation expense 11,590 11,105 22,703 21,126 Refinancing costs 638 3,507 1,751 35,591 Other, net 6,987 1,610 11,684 (841 ) Income from continuing operations before income taxes $ 247,187 $ 215,199 $ 438,151 $ 354,120 The following table presents total assets by segment (in thousands): March 31, 2018 September 30, 2017 Total assets Power & Control $ 5,177,803 $ 5,135,459 Airframe 4,021,406 3,923,172 Non-aviation 226,005 224,936 Corporate 969,463 614,594 Assets of discontinued operations — 77,500 $ 10,394,677 $ 9,975,661 The Company’s sales principally originate from the United States, and the Company’s long-lived assets are principally located in the United States.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE LOSS	6 Months Ended
	Mar. 31, 2018
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME The following table presents the components of accumulated other comprehensive (loss) income, net of taxes, for the twenty-six week period ended March 31, 2018 (in thousands): Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1) Defined benefit pension plan activity Currency translation adjustment Total Balance at September 30, 2017 $ (26,669 ) $ (16,365 ) $ (42,109 ) $ (85,143 ) Current-period other comprehensive gain 61,827 — 28,188 90,015 Amounts reclassified from AOCI related to interest rate swap and cap agreements 1,647 — — 1,647 Balance at March 31, 2018 $ 36,805 $ (16,365 ) $ (13,921 ) $ 6,519 (1) Unrealized gain represents interest rate swap and cap agreements, net of taxes of $(14,290) and $(1,310) for the thirteen week periods ended March 31, 2018 and April 1, 2017 and $(24,725) and $(24,427) for the twenty-six week period s ended March 31, 2018 and April 1, 2017 , respectively. A summary of reclassifications out of accumulated other comprehensive (loss) income for the twenty-six week period s ended March 31, 2018 and April 1, 2017 is provided below (in thousands): Amount reclassified Twenty-Six Week Periods Ended Description of reclassifications out of accumulated other comprehensive (loss) income March 31, 2018 April 1, 2017 Amortization from redesignated interest rate swap and cap agreements (1) $ 2,213 $ 1,913 Deferred tax benefit from redesignated interest rate swap and cap agreements (566 ) (715 ) Losses reclassified into earnings, net of tax $ 1,647 $ 1,198 (1) This component of accumulated other comprehensive (loss) income is included in interest expense (see Note 11, “Derivatives and Hedging Activities,” for additional information).

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	6 Months Ended
	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	DISCONTINUED OPERATIONS In connection with the settlement of a Department of Justice investigation into the competitive effects of the acquisition, during the fourth quarter of 2017, the Company committed to dispose of the Schroth business. Therefore, Schroth was classified as held-for-sale in the fourth quarter of 2017. The results of operations of Schroth are reflected as discontinued operations in the accompanying consolidated financial statements for all periods presented. On January 26, 2018, the Company completed the sale of Schroth in a management buyout to a private equity fund and certain members of Schroth management for approximately $61.4 million , subject to a working capital adjustment. The Company previously acquired Schroth in February 2017 (refer to Note 3, “Acquisitions and Divestitures”). The loss from discontinued operations was $5.6 million and $2.8 million in the condensed consolidated statements of income for the thirteen and twenty-six week periods ended March 31, 2018 . The loss from discontinued operations was $0.2 million in the condensed consolidated statements of income for the thirteen and twenty-six week periods ended April 1, 2017. Previously, in the fourth quarter of 2017, we recorded a $32.0 million impairment charge to write down the Schroth assets to fair value. The impairment charge was based on an internal assessment of the recovery of Schroth’s assets. The following is the summarized operating results for Schroth for the thirteen and twenty-six week periods ended March 31, 2018 and April 1, 2017 (in thousands): Thirteen Week Period Ended Twenty-six Week Period Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 Net sales $ 2,679 $ 4,504 $ 11,808 $ 4,504 (Loss) income from discontinued operations before income taxes (456 ) (186 ) 354 (186 ) Income tax benefit 62 — 2,016 — (Loss) income from discontinued operations, net of tax (394 ) (186 ) 2,370 (186 ) Net loss on sale of discontinued operations, net of tax (5,168 ) — (5,168 ) — Loss from discontinued operations $ (5,562 ) $ (186 ) $ (2,798 ) $ (186 )

SUBSEQUENT EVENTS (Notes)

SUBSEQUENT EVENTS (Notes)	6 Months Ended
	Mar. 31, 2018
Subsequent Event [Line Items]
Subsequent Events [Text Block]	SUBSEQUENT EVENTS On April 24, 2018, the Company completed the acquisition of Extant Components Group Holdings, Inc. (“Extant”), a portfolio company of Warburg Pincus LLC, for approximately $525 million , subject to adjustment. TransDigm financed the acquisition with cash on hand. Extant provides a broad range of proprietary aftermarket products and repair and overhaul services to the aerospace and defense end markets. Extant will be included in TransDigm's Power & Control segment. Extant is owned by an equity fund sponsored by Warburg Pincus LLC. Michael Graff, a director of TransDigm, is a managing director of Warburg Pincus LLC and is chairman of the board of Extant. Robert Henderson, Vice Chairman of TransDigm, is also on the board of Extant and owns less than 2% of Extant on a fully diluted basis. In addition, Mr. Graff, Mr. W. Nicholas Howley, TransDigm's Executive Chairman, and Messrs. Douglas Peacock and David Barr, directors of TransDigm, each have minority interests of less than 1% in the Warburg Pincus LLC fund that owns Extant. On May 1, 2018, the Company launched a proposed offering of $500 million aggregate principal amount of senior subordinated notes due 2026 by TransDigm UK Holdings plc, its wholly-owned subsidiary, pursuant to a confidential offering memorandum in a private placement under Rule 144A and Regulation S of the Securities Act of 1933. In the offering memorandum, the Company discloses that it expects to incur $700 million in additional tranche E term loans and reprice the existing tranche E term loans and tranche F term loans, in each case from existing and new lenders under the senior secured credit facilities.

SUPPLEMENTAL GUARANTOR INFORMAT

SUPPLEMENTAL GUARANTOR INFORMATION	6 Months Ended
	Mar. 31, 2018
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
SUPPLEMENTAL GUARANTOR INFORMATION	SUPPLEMENTAL GUARANTOR INFORMATION TransDigm’s 2020 Notes, 2022 Notes, 2024 Notes, 2025 Notes and 2026 Notes are jointly and severally guaranteed, on a senior subordinated basis, by TD Group and TransDigm Inc.’s 100% Domestic Restricted Subsidiaries, as defined in the Indentures. The following supplemental condensed consolidating financial information presents, in separate columns, the balance sheets of the Company as of March 31, 2018 and September 30, 2017 and its statements of income and comprehensive income and cash flows for the twenty-six week period s ended March 31, 2018 and April 1, 2017 for (i) TransDigm Group on a parent only basis with its investment in subsidiaries recorded under the equity method, (ii) TransDigm Inc. including its directly owned operations and non-operating entities, (iii) the Subsidiary Guarantors on a combined basis, (iv) Non-Guarantor Subsidiaries and (v) the Company on a consolidated basis. Separate financial statements of TransDigm Inc. are not presented because TransDigm Inc.’s 2020 Notes, 2022 Notes, 2024 Notes, 2025 Notes and 2026 Notes are fully and unconditionally guaranteed on a senior subordinated basis by TD Group and all existing 100% owned domestic subsidiaries of TransDigm Inc. and because TD Group has no significant operations or assets separate from its investment in TransDigm Inc. TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING BALANCE SHEET AS OF MARCH 31, 2018 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated ASSETS CURRENT ASSETS: Cash and cash equivalents $ 14,621 $ 817,685 $ 3,284 $ 175,417 $ — $ 1,011,007 Trade accounts receivable - Net — — 13,998 652,816 (21,829 ) 644,985 Inventories - Net — 46,100 603,775 120,414 (3,057 ) 767,232 Prepaid expenses and other — 7,477 23,855 15,548 — 46,880 Total current assets 14,621 871,262 644,912 964,195 (24,886 ) 2,470,104 INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES (2,323,958 ) 10,255,472 8,266,878 2,698,962 (18,897,354 ) — PROPERTY, PLANT AND EQUIPMENT - NET — 15,611 286,939 49,906 — 352,456 GOODWILL — 82,553 5,006,108 670,044 — 5,758,705 OTHER INTANGIBLE ASSETS - NET — 26,907 1,422,511 250,991 — 1,700,409 OTHER — 78,068 29,107 5,828 — 113,003 TOTAL ASSETS $ (2,309,337 ) $ 11,329,873 $ 15,656,455 $ 4,639,926 $ (18,922,240 ) $ 10,394,677 LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY CURRENT LIABILITIES: Current portion of long-term debt $ — $ 69,147 $ — $ — $ — $ 69,147 Short-term borrowings - trade receivable securitization facility — — — 299,833 — 299,833 Accounts payable — 16,951 116,868 37,513 (19,623 ) 151,709 Accrued liabilities — 113,827 128,807 49,512 — 292,146 Total current liabilities — 199,925 245,675 386,858 (19,623 ) 812,835 LONG-TERM DEBT — 11,365,790 — — — 11,365,790 DEFERRED INCOME TAXES — 300,255 113 58,974 — 359,342 OTHER NON-CURRENT LIABILITIES — 68,538 69,243 28,266 — 166,047 Total liabilities — 11,934,508 315,031 474,098 (19,623 ) 12,704,014 STOCKHOLDERS’ (DEFICIT) EQUITY (2,309,337 ) (604,635 ) 15,341,424 4,165,828 (18,902,617 ) (2,309,337 ) TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY $ (2,309,337 ) $ 11,329,873 $ 15,656,455 $ 4,639,926 $ (18,922,240 ) $ 10,394,677 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING BALANCE SHEET AS OF SEPTEMBER 30, 2017 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated ASSETS CURRENT ASSETS: Cash and cash equivalents $ 2,416 $ 439,473 $ (203 ) $ 208,875 $ — $ 650,561 Trade accounts receivable - Net — — 25,069 652,807 (41,749 ) 636,127 Inventories - Net — 47,051 571,712 114,018 (2,100 ) 730,681 Assets held-for-sale — — 6,428 71,072 — 77,500 Prepaid expenses and other — 4,746 24,141 9,796 — 38,683 Total current assets 2,416 491,270 627,147 1,056,568 (43,849 ) 2,133,552 INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES (2,953,620 ) 10,263,999 7,599,210 966,675 (15,876,264 ) — PROPERTY, PLANT AND EQUIPMENT - NET — 16,032 261,434 47,458 — 324,924 GOODWILL — 85,905 4,996,034 663,399 — 5,745,338 OTHER INTANGIBLE ASSETS - NET — 27,620 1,438,006 252,236 — 1,717,862 OTHER — 20,316 27,567 6,102 — 53,985 TOTAL ASSETS $ (2,951,204 ) $ 10,905,142 $ 14,949,398 $ 2,992,438 $ (15,920,113 ) $ 9,975,661 LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY CURRENT LIABILITIES: Current portion of long-term debt $ — $ 69,454 $ — $ — $ — $ 69,454 Short-term borrowings - trade receivable securitization facility — — — 299,587 — 299,587 Accounts payable — 14,712 137,948 37,667 (41,566 ) 148,761 Accrued liabilities — 180,916 103,902 51,070 — 335,888 Liabilities held-for-sale — — — 17,304 — 17,304 Total current liabilities — 265,082 241,850 405,628 (41,566 ) 870,994 LONG-TERM DEBT — 11,393,620 — — — 11,393,620 DEFERRED INCOME TAXES — 442,415 (99 ) 58,633 — 500,949 OTHER NON-CURRENT LIABILITIES — 61,347 73,245 26,710 — 161,302 Total liabilities — 12,162,464 314,996 490,971 (41,566 ) 12,926,865 STOCKHOLDERS’ (DEFICIT) EQUITY (2,951,204 ) (1,257,322 ) 14,634,402 2,501,467 (15,878,547 ) (2,951,204 ) TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY $ (2,951,204 ) $ 10,905,142 $ 14,949,398 $ 2,992,438 $ (15,920,113 ) $ 9,975,661 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF INCOME AND COMPREHENSIVE INCOME FOR THE TWENTY-SIX WEEK PERIOD ENDED MARCH 31, 2018 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET SALES $ — $ 77,215 $ 1,441,477 $ 301,750 $ (39,412 ) $ 1,781,030 COST OF SALES — 43,858 577,494 188,366 (39,412 ) 770,306 GROSS PROFIT — 33,357 863,983 113,384 — 1,010,724 SELLING AND ADMINISTRATIVE EXPENSES — 48,893 103,779 61,382 — 214,054 AMORTIZATION OF INTANGIBLE ASSETS — 714 29,709 4,146 — 34,569 (LOSS) INCOME FROM OPERATIONS — (16,250 ) 730,495 47,856 — 762,101 INTEREST EXPENSE (INCOME) - NET — 318,138 (2 ) 4,063 — 322,199 REFINANCING COSTS — 1,751 — — — 1,751 EQUITY IN INCOME OF SUBSIDIARIES (511,053 ) (562,544 ) — — 1,073,597 — INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES 511,053 226,405 730,497 43,793 (1,073,597 ) 438,151 INCOME TAX PROVISION — (284,648 ) 202,265 6,683 — (75,700 ) INCOME FROM CONTINUING OPERATIONS 511,053 511,053 528,232 37,110 (1,073,597 ) 513,851 (LOSS) INCOME FROM DISCONTINUED OPERATIONS, NET OF TAX — — (17,869 ) 15,071 — (2,798 ) NET INCOME $ 511,053 $ 511,053 $ 510,363 $ 52,181 $ (1,073,597 ) $ 511,053 OTHER COMPREHENSIVE INCOME, NET OF TAX 91,662 64,166 9,719 55,674 (129,559 ) 91,662 TOTAL COMPREHENSIVE INCOME $ 602,715 $ 575,219 $ 520,082 $ 107,855 $ (1,203,156 ) $ 602,715 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF INCOME AND COMPREHENSIVE INCOME FOR THE TWENTY-SIX WEEK PERIOD ENDED APRIL 1, 2017 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET SALES $ — $ 65,037 $ 1,409,050 $ 249,256 $ (40,597 ) $ 1,682,746 COST OF SALES — 36,230 605,288 148,133 (40,597 ) 749,054 GROSS PROFIT — 28,807 803,762 101,123 — 933,692 SELLING AND ADMINISTRATIVE EXPENSES 61 47,474 127,391 27,646 — 202,572 AMORTIZATION OF INTANGIBLE ASSETS — 387 43,108 4,068 — 47,563 (LOSS) INCOME FROM OPERATIONS (61 ) (19,054 ) 633,263 69,409 — 683,557 INTEREST EXPENSE (INCOME) - NET — 298,005 (31 ) (4,128 ) — 293,846 REFINANCING COSTS — 35,591 — — — 35,591 EQUITY IN INCOME OF SUBSIDIARIES (274,437 ) (629,721 ) — — 904,158 — INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES 274,376 277,071 633,294 73,537 (904,158 ) 354,120 INCOME TAX PROVISION — 2,634 73,549 3,375 — 79,558 INCOME FROM CONTINUING OPERATIONS 274,376 274,437 559,745 70,162 (904,158 ) 274,562 (LOSS) INCOME FROM DISCONTINUED OPERATIONS, NET OF TAX — — (423 ) 237 (186 ) NET INCOME $ 274,376 $ 274,437 $ 559,322 $ 70,399 $ (904,158 ) $ 274,376 OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX 20,952 40,955 15,012 (59,324 ) 3,357 20,952 TOTAL COMPREHENSIVE INCOME $ 295,328 $ 315,392 $ 574,334 $ 11,075 $ (900,801 ) $ 295,328 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE TWENTY-SIX WEEK PERIOD ENDED MARCH 31, 2018 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES $ — $ (157,892 ) $ 578,789 $ 29,807 $ 2,980 $ 453,684 INVESTING ACTIVITIES: Capital expenditures — (826 ) (27,370 ) (2,688 ) — (30,884 ) Payments made in connection with acquisitions — (50,320 ) — — — (50,320 ) Proceeds in connection with sale of discontinued operations — 57,686 — — — 57,686 Net cash provided by (used in) investing activities — 6,540 (27,370 ) (2,688 ) — (23,518 ) FINANCING ACTIVITIES: Intercompany activities 42,048 571,729 (547,932 ) (62,865 ) (2,980 ) — Proceeds from exercise of stock options 26,305 — — — — 26,305 Special dividend and dividend equivalent payments (56,148 ) — — — — (56,148 ) Proceeds from term loans, net — 793,042 — — — 793,042 Repayment on term loans — (833,052 ) — — — (833,052 ) Other — (2,155 ) — — — (2,155 ) Net cash provided by (used in) financing activities 12,205 529,564 (547,932 ) (62,865 ) (2,980 ) (72,008 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS — — — 2,288 — 2,288 INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS 12,205 378,212 3,487 (33,458 ) — 360,446 CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD 2,416 439,473 (203 ) 208,875 — 650,561 CASH AND CASH EQUIVALENTS, END OF PERIOD $ 14,621 $ 817,685 $ 3,284 $ 175,417 $ — $ 1,011,007 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE TWENTY-SIX WEEK PERIOD ENDED APRIL 1, 2017 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES $ (61 ) $ (332,771 ) $ 720,181 $ 2,035 $ 1,116 $ 390,500 INVESTING ACTIVITIES: Capital expenditures (829 ) (34,576 ) (3,031 ) — (38,436 ) Payments made in connection with acquisitions (30,002 ) (30,002 ) Payments made in connection with purchase of discontinued operations — (78,879 ) — — — (78,879 ) Net cash used in investing activities — (109,710 ) (34,576 ) (3,031 ) — (147,317 ) FINANCING ACTIVITIES: Intercompany activities 1,691,169 (1,028,726 ) (693,345 ) 32,018 (1,116 ) — Proceeds from exercise of stock options 12,345 — — — — 12,345 Special dividend and dividend equivalent payments (1,375,998 ) — — — — (1,375,998 ) Treasury stock repurchased (339,833 ) — — — — (339,833 ) Proceeds from term loans, net — 1,132,774 — — — 1,132,774 Repayment on term loans — (32,302 ) — — — (32,302 ) Proceeds from additional 2025 Notes offering, net — 301,006 — — — 301,006 Cash tender and redemption of the 2021 Notes, including premium — (528,847 ) — — — (528,847 ) Other — (10,745 ) — — — (10,745 ) Net cash (used in) provided by financing activities (12,317 ) (166,840 ) (693,345 ) 32,018 (1,116 ) (841,600 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS — — — (3,188 ) — (3,188 ) (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS (12,378 ) (609,321 ) (7,740 ) 27,834 — (601,605 ) CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD 13,560 1,421,251 8,808 143,375 — 1,586,994 CASH AND CASH EQUIVALENTS, END OF PERIOD $ 1,182 $ 811,930 $ 1,068 $ 171,209 $ — $ 985,389

RECENT ACCOUNTING PRONOUNCEME24

RECENT ACCOUNTING PRONOUNCEMENTS (Policies)	6 Months Ended
	Mar. 31, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, which created a new topic in the Accounting Standards Codification (“ASC”) 606, “Revenue From Contracts With Customers .” In addition to superseding and replacing nearly all existing U.S. GAAP revenue recognition guidance, including industry-specific guidance, ASC 606 establishes a new control-based revenue recognition model. The new revenue standards may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. The guidance is effective for the Company for annual reporting periods, including interim periods therein, beginning October 1, 2018, which is the Company’s planned date of adoption. The Company expects to use the modified retrospective method. The Company is continuing to evaluate the impact of the standard. For each reporting unit, we have evaluated a representative sample of contracts and other agreements with our customers and evaluated the provisions contained within these contracts and agreements in consideration of the five step model specified within ASC 606. We are in the process of documenting the impact of the standard on our current accounting policies and practices in order to identify material differences, if any, that would result from applying the new requirements to our revenue contracts. We continue to make progress on our assessment of ASC 606 and are also in the process of evaluating the impact, if any, on changes to our business processes, systems, and controls to support recognition and disclosure requirements under ASC 606. In February 2016, the FASB issued ASU 2016-02, “Leases (ASC 842),” which will require that a lessee recognize assets and liabilities on the balance sheet for all leases with a lease term of more than twelve months, with the result being the recognition of a right of use asset and a lease liability. The guidance is effective for the Company for annual reporting periods, including interim periods therein, beginning October 1, 2019, with early adoption permitted. The Company is currently evaluating the impact of adopting this standard on its consolidated financial statements and disclosures. In June 2016, the FASB issued ASU 2016-13, "Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (ASU 2016-13)," which changes the impairment model for most financial assets. The new model uses a forward-looking expected loss method, which will generally result in earlier recognition of allowances for losses. ASU 2016-13 is effective for annual and interim periods beginning after December 15, 2019 and early adoption is permitted for annual and interim periods beginning after December 15, 2018. The Company is currently evaluating the impact of adopting this standard on its consolidated financial statements and disclosures. In August 2016, the FASB issued ASU 2016-15, "Statement of Cash Flows—Classification of Certain Cash Receipts and Cash Payments," which clarifies existing guidance related to accounting for cash receipts and cash payments and classification on the statement of cash flows. This guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted. The Company elected to early adopt this standard in the fourth quarter of fiscal 2017. The adoption of this standard did not have a material impact on its consolidated statement of cash flows. In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment,” to eliminate Step 2 from the goodwill impairment test in order to simplify the subsequent measurement of goodwill. The guidance is effective for fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this standard is not expected to have a material impact on its consolidated financial statements and disclosures. In March 2017, the FASB issued ASU 2017-07, "Compensation—Retirement Benefits (ASC 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost," that will change how employers that sponsor defined benefit and/or other postretirement benefit plans present the net periodic benefit cost in the income statement. Under the new guidance, employers will present the service cost component of the net periodic benefit cost in the same income statement line item(s) as other employee compensation costs arising from services rendered during the period. In addition, only the service cost component will be eligible for capitalization in assets. Employers will present the other components separately from the line item(s) that includes the service cost and outside of any subtotal of operating income, if one is presented. Employers will have to disclose the line(s) used to present the other components of net periodic benefit cost, if the components are not presented separately in the income statement.The standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within the fiscal year. Early adoption is permitted, including adoption in any interim period for which financial statements have not yet been issued. The adoption of this standard is not expected to have a material impact on our consolidated financial statements. In May 2017, the FASB issued ASU 2017-09, "Compensation—Stock Compensation (ASC 718): Scope of Modification Accounting," which provides clarity on which changes to the terms or conditions of share-based payment awards require an entity to apply the modification accounting provisions required in ASC 718. The standard is effective for all entities for annual periods beginning after December 15, 2017, with early adoption permitted, including adoption in any interim period for which financial statements have not yet been issued. The adoption of this standard is not expected to have a material impact on our consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging (ASC 815): Targeted Improvements to Accounting for Hedging Activities,” which amends the FASB’s hedge accounting model to enable entities to better portray their risk management activities in financial statements. The guidance eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance also eases certain documentation and assessment requirements and modifies the accounting for components excluded from the assessment of hedge effectiveness. ASU 2017-12 is effective for the Company for annual reporting periods, including interim periods therein, beginning October 1, 2018, with early adoption permitted. As early adoption is permissible, the Company adopted the pronouncement beginning October 1, 2017. Changes were applied prospectively in accordance with the standard and prior periods were not adjusted. The adoption of this standard did not have a material impact on our consolidated financial statements and disclosures. In February 2018, the FASB issued ASU 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income," which gives entities the option to reclassify tax effects stranded in accumulated other comprehensive income as a result of the Tax Cuts and Jobs Act (the "Act") into retained earnings. The guidance allows entities to reclassify from accumulated other comprehensive income to retained earnings stranded tax effects resulting from the Act's new federal corporate income tax rate. The guidance also allows entities to elect to reclassify other stranded tax effects that relate to the Act but do not directly relate to the change in the federal tax rate (e.g., state taxes, changing from a worldwide tax system to a territorial system). Tax effects that are stranded in accumulated other comprehensive income for other reasons (e.g., prior changes in tax law, a change in valuation allowance) may not be reclassified. The standard is effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within the fiscal year. Early adoption is permitted, including adoption in any interim period for which financial statements have not yet been issued. Entities have the option to apply the guidance retrospectively or in the period of adoption. The adoption of this standard is not expected to have a material impact on our consolidated financial statements. In March 2018, the FASB issued ASU 2018-05, “Income Taxes (Topic 740), Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118.” The ASU adds various SEC paragraphs pursuant to the issuance of the December 2017 SEC Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”), which was effective immediately. The SEC issued SAB 118 to address concerns about reporting entities’ ability to timely comply with the accounting requirements to recognize all of the effects of the Tax Cuts and Jobs Act in the period of enactment. SAB 118 allows disclosure that timely determination of some or all of the income tax effects from the Tax Cuts and Jobs Act are incomplete by the due date of the financial statements and if possible to provide a reasonable estimate. We have accounted for the tax effects of the Tax Cuts and Jobs Act under the guidance of SAB 118, on a provisional basis. Our accounting for certain income tax effects is incomplete, but we have determined reasonable estimates for those effects and have recorded provisional amounts in our condensed consolidated financial statements. Refer to Note 9, "Income Taxes," for further information.

EARNINGS PER SHARE (TWO-CLASS25

EARNINGS PER SHARE (TWO-CLASS METHOD) (Tables)	6 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share (in thousands, except per share data): Thirteen Week Periods Ended Twenty-Six Week Periods Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 Numerator for earnings per share: Net income from continuing operations $ 201,840 $ 155,691 $ 513,851 $ 274,562 Less dividends paid on participating securities — — (56,148 ) (95,971 ) $ 201,840 $ 155,691 $ 457,703 $ 178,591 Net loss from discontinued operations (5,562 ) (186 ) (2,798 ) (186 ) Net income applicable to common stock - basic and diluted $ 196,278 $ 155,505 $ 454,905 $ 178,405 Denominator for basic and diluted earnings per share under the two-class method: Weighted average common shares outstanding 52,229 52,849 52,127 53,108 Vested options deemed participating securities 3,376 3,045 3,472 3,103 Total shares for basic and diluted earnings per share 55,605 55,894 55,599 56,211 Net earnings per share from continuing operations - basic and diluted $ 3.63 $ 2.78 $ 8.23 $ 3.17 Net loss per share from discontinued operations - basic and diluted $ (0.10 ) $ — (0.05 ) — Net earnings per share $ 3.53 $ 2.78 $ 8.18 $ 3.17

INVENTORIES (Tables)

INVENTORIES (Tables)	6 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories consist of the following (in thousands): March 31, 2018 September 30, 2017 Raw materials and purchased component parts $ 517,910 $ 496,899 Work-in-progress 204,940 187,009 Finished goods 134,762 131,548 Total 857,612 815,456 Reserves for excess and obsolete inventory (90,380 ) (84,775 ) Inventories - Net $ 767,232 $ 730,681

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	6 Months Ended
	Mar. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Schedule of Acquired Intangible Assets by Major Class [Table Text Block]	Intangible assets acquired during the twenty-six week period ended March 31, 2018 were as follows (in thousands): Gross Amount Amortization Period Intangible assets not subject to amortization: Goodwill $ 2,218 Trademarks and trade names 10,000 12,218 Intangible assets subject to amortization: Technology 2,000 20 years Order backlog 6,000 1 year 8,000 5.8 years Total $ 20,218
Intangible Assets Subject to Amortization	Other intangible assets - net in the condensed consolidated balance sheets consist of the following (in thousands): March 31, 2018 September 30, 2017 Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net Trademarks and trade names $ 742,028 $ — $ 742,028 $ 729,931 $ — $ 729,931 Technology 1,292,753 383,509 909,244 1,292,719 351,638 941,081 Order backlog 8,700 2,252 6,448 29,000 26,668 2,332 Other 63,382 20,693 42,689 63,599 19,081 44,518 Total $ 2,106,863 $ 406,454 $ 1,700,409 $ 2,115,249 $ 397,387 $ 1,717,862
Summary of Changes in Carrying Value of Goodwill	The following is a summary of changes in the carrying value of goodwill by segment from September 30, 2017 through March 31, 2018 (in thousands): Power & Control Airframe Non- aviation Total Balance - September 30, 2017 $ 3,269,981 $ 2,382,082 $ 93,275 $ 5,745,338 Goodwill acquired during the year — 2,218 — 2,218 Purchase price allocation adjustments 4,508 — — 4,508 Currency translation adjustment — 6,645 — 6,645 Other (191 ) 187 — (4 ) Balance - March 31, 2018 $ 3,274,298 $ 2,391,132 $ 93,275 $ 5,758,705

DEBT (Tables)

DEBT (Tables)	6 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Debt	The Company’s debt consists of the following (in thousands): March 31, 2018 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 300,000 $ (167 ) $ — $ 299,833 Term loans $ 6,938,145 $ (60,435 ) $ (18,221 ) $ 6,859,489 5 1/2% senior subordinated notes due 2020 (2020 Notes) 550,000 (2,715 ) — 547,285 6% senior subordinated notes due 2022 (2022 Notes) 1,150,000 (6,221 ) — 1,143,779 6 1/2% senior subordinated notes due 2024 (2024 Notes) 1,200,000 (7,454 ) — 1,192,546 6 1/2% senior subordinated notes due 2025 (2025 Notes) 750,000 (3,769 ) 3,909 750,140 6 3/8% senior subordinated notes due 2026 (2026 Notes) 950,000 (8,302 ) — 941,698 11,538,145 (88,896 ) (14,312 ) 11,434,937 Less current portion 69,685 (538 ) — 69,147 Long-term debt $ 11,468,460 $ (88,358 ) $ (14,312 ) $ 11,365,790 September 30, 2017 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 300,000 $ (413 ) $ — $ 299,587 Term loans $ 6,973,009 $ (64,104 ) $ (18,948 ) $ 6,889,957 2020 Notes 550,000 (3,243 ) — 546,757 2022 Notes 1,150,000 (6,941 ) — 1,143,059 2024 Notes 1,200,000 (8,042 ) — 1,191,958 2025 Notes 750,000 (4,033 ) 4,182 750,149 2026 Notes 950,000 (8,806 ) — 941,194 11,573,009 (95,169 ) (14,766 ) 11,463,074 Less current portion 70,031 (577 ) — 69,454 Long-term debt $ 11,502,978 $ (94,592 ) $ (14,766 ) $ 11,393,620

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Carrying Amounts and Fair Values of Financial Instruments	The following summarizes the carrying amounts and fair values of financial instruments (in thousands): March 31, 2018 September 30, 2017 Level Carrying Amount Fair Value Carrying Amount Fair Value Assets: Cash and cash equivalents 1 $ 1,011,007 $ 1,011,007 $ 650,561 $ 650,561 Interest rate cap agreements (1) 2 27,343 27,343 12,904 12,904 Interest rate swap agreements (2) 2 2,507 2,507 — — Interest rate swap agreements (1) 2 41,719 41,719 2,905 2,905 Liabilities: Interest rate swap agreements (3) 2 1,533 1,533 20,740 20,740 Interest rate swap agreements (4) 2 54 54 9,731 9,731 Short-term borrowings - trade receivable securitization facility (5) 1 299,833 299,833 299,587 299,587 Long-term debt, including current portion: Term loans (5) 2 6,859,489 6,935,358 6,889,957 6,965,628 2020 Notes (5) 1 547,285 552,750 546,757 558,250 2022 Notes (5) 1 1,143,779 1,173,000 1,143,059 1,178,750 2024 Notes (5) 1 1,192,546 1,230,000 1,191,958 1,236,000 2025 Notes (5) 1 750,140 765,218 750,149 776,807 2026 Notes (5) 1 941,698 954,750 941,194 971,375 (1) Included in other non-current assets on the condensed consolidated balance sheet. (2) Included in prepaid expenses and other on the condensed consolidated balance sheet. (3) Included in accrued liabilities on the condensed consolidated balance sheet. (4) Included in other non-current liabilities on the condensed consolidated balance sheet. (5) The carrying amount of the debt instrument is presented net of the debt issuance costs. Refer to Note 8, "Debt," for gross carrying amounts.

DERIVATIVES AND HEDGING ACTIV30

DERIVATIVES AND HEDGING ACTIVITIES (Tables)	6 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	The following table summarizes the Company's interest rate swap agreements: Aggregate Notional Amount (in millions) Start Date End Date Related Term Loans Conversion of Related Variable Rate Debt to Fixed Rate of: $1,000 9/30/2014 6/30/2019 Tranche G 4.90% (2.40% plus the 2.50% margin percentage) $400 9/30/2017 9/30/2022 Tranche G 4.40% (1.90% plus the 2.50% margin percentage) $750 6/30/2020 6/30/2022 Tranche F 5.25% (2.50% plus the 2.75% margin percentage) $500 12/30/2016 12/31/2021 Tranche F 4.65% (1.90% plus the 2.75% margin percentage) $1,000 6/28/2019 6/30/2021 Tranche F 4.55% (1.80% plus the 2.75% margin percentage) $750 3/31/2016 6/30/2020 Tranche F 5.55% (2.80% plus the 2.75% margin percentage) The following table summarizes the Company's interest rate cap agreements: Aggregate Notional Amount Start Date End Date Related Term Loans Offsets Variable Rate Debt Attributable to Fluctuations Above: $750 6/30/2020 6/30/2022 Tranche F Three month LIBO rate of 2.50% $400 12/30/2016 12/31/2021 Tranche F Three month LIBO rate of 2.50% $400 6/30/2016 6/30/2021 Tranche F Three month LIBO rate of 2.00% $750 9/30/2015 6/30/2020 Tranche E Three month LIBO rate of 2.50%
Schedule of Interest Rate Derivatives	March 31, 2018 September 30, 2017 Asset Liability Asset Liability Interest rate cap agreements $ 27,343 $ — $ 12,904 $ — Interest rate swap agreements 46,604 (3,965 ) 9,235 (36,801 ) Total 73,947 (3,965 ) 22,139 (36,801 ) Effect of counterparty netting (2,378 ) 2,378 (6,330 ) 6,330 Net derivatives as classified in the balance sheet (1) $ 71,569 $ (1,587 ) $ 15,809 $ (30,471 ) (1) Refer to Note 10, "Fair Value Measurements," for the condensed consolidated balance sheet classification of our interest rate swap and cap agreements.

SEGMENTS (Tables)

SEGMENTS (Tables)	6 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Net Sales by Reportable Segments	The following table presents net sales by reportable segment (in thousands): Thirteen Week Periods Ended Twenty-Six Week Periods Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 Net sales to external customers Power & Control $ 528,460 $ 473,952 $ 1,011,178 $ 909,784 Airframe 369,783 360,509 703,175 709,173 Non-aviation 34,827 34,267 66,677 63,789 $ 933,070 $ 868,728 $ 1,781,030 $ 1,682,746
EBITDA Defined by Segment to Consolidated Income Before Taxes	The following table reconciles EBITDA As Defined by segment to consolidated income from continuing operations before income taxes (in thousands): Thirteen Week Periods Ended Twenty-Six Week Periods Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 EBITDA As Defined Power & Control $ 275,562 $ 232,828 $ 520,337 $ 445,746 Airframe 186,006 182,980 344,425 351,509 Non-aviation 10,321 11,391 19,317 20,668 Total segment EBITDA As Defined 471,889 427,199 884,079 817,923 Unallocated corporate expenses 8,766 5,523 19,423 15,053 Total Company EBITDA As Defined 463,123 421,676 864,656 802,870 Depreciation and amortization expense 30,970 34,661 61,609 72,708 Interest expense - net 161,266 147,842 322,199 293,846 Acquisition-related costs 4,485 7,752 6,559 26,320 Stock compensation expense 11,590 11,105 22,703 21,126 Refinancing costs 638 3,507 1,751 35,591 Other, net 6,987 1,610 11,684 (841 ) Income from continuing operations before income taxes $ 247,187 $ 215,199 $ 438,151 $ 354,120
Total Assets by Segment	The following table presents total assets by segment (in thousands): March 31, 2018 September 30, 2017 Total assets Power & Control $ 5,177,803 $ 5,135,459 Airframe 4,021,406 3,923,172 Non-aviation 226,005 224,936 Corporate 969,463 614,594 Assets of discontinued operations — 77,500 $ 10,394,677 $ 9,975,661

ACCUMULATED OTHER COMPREHENSI32

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	6 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Loss	The following table presents the components of accumulated other comprehensive (loss) income, net of taxes, for the twenty-six week period ended March 31, 2018 (in thousands): Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1) Defined benefit pension plan activity Currency translation adjustment Total Balance at September 30, 2017 $ (26,669 ) $ (16,365 ) $ (42,109 ) $ (85,143 ) Current-period other comprehensive gain 61,827 — 28,188 90,015 Amounts reclassified from AOCI related to interest rate swap and cap agreements 1,647 — — 1,647 Balance at March 31, 2018 $ 36,805 $ (16,365 ) $ (13,921 ) $ 6,519 (1) Unrealized gain represents interest rate swap and cap agreements, net of taxes of $(14,290) and $(1,310) for the thirteen week periods ended March 31, 2018 and April 1, 2017 and $(24,725) and $(24,427) for the twenty-six week period s ended March 31, 2018 and April 1, 2017 , respectively.
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	A summary of reclassifications out of accumulated other comprehensive (loss) income for the twenty-six week period s ended March 31, 2018 and April 1, 2017 is provided below (in thousands): Amount reclassified Twenty-Six Week Periods Ended Description of reclassifications out of accumulated other comprehensive (loss) income March 31, 2018 April 1, 2017 Amortization from redesignated interest rate swap and cap agreements (1) $ 2,213 $ 1,913 Deferred tax benefit from redesignated interest rate swap and cap agreements (566 ) (715 ) Losses reclassified into earnings, net of tax $ 1,647 $ 1,198 (1) This component of accumulated other comprehensive (loss) income is included in interest expense (see Note 11, “Derivatives and Hedging Activities,” for additional information).

DISCONTINUED OPERATIONS (Tables

DISCONTINUED OPERATIONS (Tables)	6 Months Ended
	Mar. 31, 2018
DISCONTINUED OPERATIONS [Abstract]
Disposal Groups, Including Discontinued Operations [Table Text Block]	The following is the summarized operating results for Schroth for the thirteen and twenty-six week periods ended March 31, 2018 and April 1, 2017 (in thousands): Thirteen Week Period Ended Twenty-six Week Period Ended March 31, 2018 April 1, 2017 March 31, 2018 April 1, 2017 Net sales $ 2,679 $ 4,504 $ 11,808 $ 4,504 (Loss) income from discontinued operations before income taxes (456 ) (186 ) 354 (186 ) Income tax benefit 62 — 2,016 — (Loss) income from discontinued operations, net of tax (394 ) (186 ) 2,370 (186 ) Net loss on sale of discontinued operations, net of tax (5,168 ) — (5,168 ) — Loss from discontinued operations $ (5,562 ) $ (186 ) $ (2,798 ) $ (186 )

SUPPLEMENTAL GUARANTOR INFORM34

SUPPLEMENTAL GUARANTOR INFORMATION (Tables)	6 Months Ended
	Mar. 31, 2018
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Supplemental Condensed Consolidating Balance Sheet	TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING BALANCE SHEET AS OF MARCH 31, 2018 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated ASSETS CURRENT ASSETS: Cash and cash equivalents $ 14,621 $ 817,685 $ 3,284 $ 175,417 $ — $ 1,011,007 Trade accounts receivable - Net — — 13,998 652,816 (21,829 ) 644,985 Inventories - Net — 46,100 603,775 120,414 (3,057 ) 767,232 Prepaid expenses and other — 7,477 23,855 15,548 — 46,880 Total current assets 14,621 871,262 644,912 964,195 (24,886 ) 2,470,104 INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES (2,323,958 ) 10,255,472 8,266,878 2,698,962 (18,897,354 ) — PROPERTY, PLANT AND EQUIPMENT - NET — 15,611 286,939 49,906 — 352,456 GOODWILL — 82,553 5,006,108 670,044 — 5,758,705 OTHER INTANGIBLE ASSETS - NET — 26,907 1,422,511 250,991 — 1,700,409 OTHER — 78,068 29,107 5,828 — 113,003 TOTAL ASSETS $ (2,309,337 ) $ 11,329,873 $ 15,656,455 $ 4,639,926 $ (18,922,240 ) $ 10,394,677 LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY CURRENT LIABILITIES: Current portion of long-term debt $ — $ 69,147 $ — $ — $ — $ 69,147 Short-term borrowings - trade receivable securitization facility — — — 299,833 — 299,833 Accounts payable — 16,951 116,868 37,513 (19,623 ) 151,709 Accrued liabilities — 113,827 128,807 49,512 — 292,146 Total current liabilities — 199,925 245,675 386,858 (19,623 ) 812,835 LONG-TERM DEBT — 11,365,790 — — — 11,365,790 DEFERRED INCOME TAXES — 300,255 113 58,974 — 359,342 OTHER NON-CURRENT LIABILITIES — 68,538 69,243 28,266 — 166,047 Total liabilities — 11,934,508 315,031 474,098 (19,623 ) 12,704,014 STOCKHOLDERS’ (DEFICIT) EQUITY (2,309,337 ) (604,635 ) 15,341,424 4,165,828 (18,902,617 ) (2,309,337 ) TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY $ (2,309,337 ) $ 11,329,873 $ 15,656,455 $ 4,639,926 $ (18,922,240 ) $ 10,394,677 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING BALANCE SHEET AS OF SEPTEMBER 30, 2017 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated ASSETS CURRENT ASSETS: Cash and cash equivalents $ 2,416 $ 439,473 $ (203 ) $ 208,875 $ — $ 650,561 Trade accounts receivable - Net — — 25,069 652,807 (41,749 ) 636,127 Inventories - Net — 47,051 571,712 114,018 (2,100 ) 730,681 Assets held-for-sale — — 6,428 71,072 — 77,500 Prepaid expenses and other — 4,746 24,141 9,796 — 38,683 Total current assets 2,416 491,270 627,147 1,056,568 (43,849 ) 2,133,552 INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES (2,953,620 ) 10,263,999 7,599,210 966,675 (15,876,264 ) — PROPERTY, PLANT AND EQUIPMENT - NET — 16,032 261,434 47,458 — 324,924 GOODWILL — 85,905 4,996,034 663,399 — 5,745,338 OTHER INTANGIBLE ASSETS - NET — 27,620 1,438,006 252,236 — 1,717,862 OTHER — 20,316 27,567 6,102 — 53,985 TOTAL ASSETS $ (2,951,204 ) $ 10,905,142 $ 14,949,398 $ 2,992,438 $ (15,920,113 ) $ 9,975,661 LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY CURRENT LIABILITIES: Current portion of long-term debt $ — $ 69,454 $ — $ — $ — $ 69,454 Short-term borrowings - trade receivable securitization facility — — — 299,587 — 299,587 Accounts payable — 14,712 137,948 37,667 (41,566 ) 148,761 Accrued liabilities — 180,916 103,902 51,070 — 335,888 Liabilities held-for-sale — — — 17,304 — 17,304 Total current liabilities — 265,082 241,850 405,628 (41,566 ) 870,994 LONG-TERM DEBT — 11,393,620 — — — 11,393,620 DEFERRED INCOME TAXES — 442,415 (99 ) 58,633 — 500,949 OTHER NON-CURRENT LIABILITIES — 61,347 73,245 26,710 — 161,302 Total liabilities — 12,162,464 314,996 490,971 (41,566 ) 12,926,865 STOCKHOLDERS’ (DEFICIT) EQUITY (2,951,204 ) (1,257,322 ) 14,634,402 2,501,467 (15,878,547 ) (2,951,204 ) TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY $ (2,951,204 ) $ 10,905,142 $ 14,949,398 $ 2,992,438 $ (15,920,113 ) $ 9,975,661
Supplemental Condensed Consolidating Income Statement	TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF INCOME AND COMPREHENSIVE INCOME FOR THE TWENTY-SIX WEEK PERIOD ENDED MARCH 31, 2018 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET SALES $ — $ 77,215 $ 1,441,477 $ 301,750 $ (39,412 ) $ 1,781,030 COST OF SALES — 43,858 577,494 188,366 (39,412 ) 770,306 GROSS PROFIT — 33,357 863,983 113,384 — 1,010,724 SELLING AND ADMINISTRATIVE EXPENSES — 48,893 103,779 61,382 — 214,054 AMORTIZATION OF INTANGIBLE ASSETS — 714 29,709 4,146 — 34,569 (LOSS) INCOME FROM OPERATIONS — (16,250 ) 730,495 47,856 — 762,101 INTEREST EXPENSE (INCOME) - NET — 318,138 (2 ) 4,063 — 322,199 REFINANCING COSTS — 1,751 — — — 1,751 EQUITY IN INCOME OF SUBSIDIARIES (511,053 ) (562,544 ) — — 1,073,597 — INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES 511,053 226,405 730,497 43,793 (1,073,597 ) 438,151 INCOME TAX PROVISION — (284,648 ) 202,265 6,683 — (75,700 ) INCOME FROM CONTINUING OPERATIONS 511,053 511,053 528,232 37,110 (1,073,597 ) 513,851 (LOSS) INCOME FROM DISCONTINUED OPERATIONS, NET OF TAX — — (17,869 ) 15,071 — (2,798 ) NET INCOME $ 511,053 $ 511,053 $ 510,363 $ 52,181 $ (1,073,597 ) $ 511,053 OTHER COMPREHENSIVE INCOME, NET OF TAX 91,662 64,166 9,719 55,674 (129,559 ) 91,662 TOTAL COMPREHENSIVE INCOME $ 602,715 $ 575,219 $ 520,082 $ 107,855 $ (1,203,156 ) $ 602,715 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF INCOME AND COMPREHENSIVE INCOME FOR THE TWENTY-SIX WEEK PERIOD ENDED APRIL 1, 2017 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET SALES $ — $ 65,037 $ 1,409,050 $ 249,256 $ (40,597 ) $ 1,682,746 COST OF SALES — 36,230 605,288 148,133 (40,597 ) 749,054 GROSS PROFIT — 28,807 803,762 101,123 — 933,692 SELLING AND ADMINISTRATIVE EXPENSES 61 47,474 127,391 27,646 — 202,572 AMORTIZATION OF INTANGIBLE ASSETS — 387 43,108 4,068 — 47,563 (LOSS) INCOME FROM OPERATIONS (61 ) (19,054 ) 633,263 69,409 — 683,557 INTEREST EXPENSE (INCOME) - NET — 298,005 (31 ) (4,128 ) — 293,846 REFINANCING COSTS — 35,591 — — — 35,591 EQUITY IN INCOME OF SUBSIDIARIES (274,437 ) (629,721 ) — — 904,158 — INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES 274,376 277,071 633,294 73,537 (904,158 ) 354,120 INCOME TAX PROVISION — 2,634 73,549 3,375 — 79,558 INCOME FROM CONTINUING OPERATIONS 274,376 274,437 559,745 70,162 (904,158 ) 274,562 (LOSS) INCOME FROM DISCONTINUED OPERATIONS, NET OF TAX — — (423 ) 237 (186 ) NET INCOME $ 274,376 $ 274,437 $ 559,322 $ 70,399 $ (904,158 ) $ 274,376 OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX 20,952 40,955 15,012 (59,324 ) 3,357 20,952 TOTAL COMPREHENSIVE INCOME $ 295,328 $ 315,392 $ 574,334 $ 11,075 $ (900,801 ) $ 295,328
Supplemental Condensed Consolidating Cash Flow Statement	TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE TWENTY-SIX WEEK PERIOD ENDED MARCH 31, 2018 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES $ — $ (157,892 ) $ 578,789 $ 29,807 $ 2,980 $ 453,684 INVESTING ACTIVITIES: Capital expenditures — (826 ) (27,370 ) (2,688 ) — (30,884 ) Payments made in connection with acquisitions — (50,320 ) — — — (50,320 ) Proceeds in connection with sale of discontinued operations — 57,686 — — — 57,686 Net cash provided by (used in) investing activities — 6,540 (27,370 ) (2,688 ) — (23,518 ) FINANCING ACTIVITIES: Intercompany activities 42,048 571,729 (547,932 ) (62,865 ) (2,980 ) — Proceeds from exercise of stock options 26,305 — — — — 26,305 Special dividend and dividend equivalent payments (56,148 ) — — — — (56,148 ) Proceeds from term loans, net — 793,042 — — — 793,042 Repayment on term loans — (833,052 ) — — — (833,052 ) Other — (2,155 ) — — — (2,155 ) Net cash provided by (used in) financing activities 12,205 529,564 (547,932 ) (62,865 ) (2,980 ) (72,008 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS — — — 2,288 — 2,288 INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS 12,205 378,212 3,487 (33,458 ) — 360,446 CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD 2,416 439,473 (203 ) 208,875 — 650,561 CASH AND CASH EQUIVALENTS, END OF PERIOD $ 14,621 $ 817,685 $ 3,284 $ 175,417 $ — $ 1,011,007 TRANSDIGM GROUP INCORPORATED CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE TWENTY-SIX WEEK PERIOD ENDED APRIL 1, 2017 (Amounts in thousands) TransDigm Group TransDigm Inc. Subsidiary Guarantors Non- Guarantor Subsidiaries Eliminations Total Consolidated NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES $ (61 ) $ (332,771 ) $ 720,181 $ 2,035 $ 1,116 $ 390,500 INVESTING ACTIVITIES: Capital expenditures (829 ) (34,576 ) (3,031 ) — (38,436 ) Payments made in connection with acquisitions (30,002 ) (30,002 ) Payments made in connection with purchase of discontinued operations — (78,879 ) — — — (78,879 ) Net cash used in investing activities — (109,710 ) (34,576 ) (3,031 ) — (147,317 ) FINANCING ACTIVITIES: Intercompany activities 1,691,169 (1,028,726 ) (693,345 ) 32,018 (1,116 ) — Proceeds from exercise of stock options 12,345 — — — — 12,345 Special dividend and dividend equivalent payments (1,375,998 ) — — — — (1,375,998 ) Treasury stock repurchased (339,833 ) — — — — (339,833 ) Proceeds from term loans, net — 1,132,774 — — — 1,132,774 Repayment on term loans — (32,302 ) — — — (32,302 ) Proceeds from additional 2025 Notes offering, net — 301,006 — — — 301,006 Cash tender and redemption of the 2021 Notes, including premium — (528,847 ) — — — (528,847 ) Other — (10,745 ) — — — (10,745 ) Net cash (used in) provided by financing activities (12,317 ) (166,840 ) (693,345 ) 32,018 (1,116 ) (841,600 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS — — — (3,188 ) — (3,188 ) (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS (12,378 ) (609,321 ) (7,740 ) 27,834 — (601,605 ) CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD 13,560 1,421,251 8,808 143,375 — 1,586,994 CASH AND CASH EQUIVALENTS, END OF PERIOD $ 1,182 $ 811,930 $ 1,068 $ 171,209 $ — $ 985,389

DESCRIPTION OF THE BUSINESS - N

DESCRIPTION OF THE BUSINESS - Narratives (Details)	Mar. 31, 2018
Accounting Policies [Abstract]
Percentage of ownership in subsidiary	100.00%

ACQUISITIONS - Narratives (Deta

ACQUISITIONS - Narratives (Details) - USD ($) $ in Thousands	Jan. 26, 2018	Feb. 22, 2017	Mar. 31, 2018	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2017
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				$ 50,320	$ 30,002
Minimum
Business Acquisition [Line Items]
Estimated useful life of aircraft (in years)				25 years
Maximum
Business Acquisition [Line Items]
Estimated useful life of aircraft (in years)				30 years
Kirkhill [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired						$ 50,000
Third Quarter 2017 Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition Purchase Price Adjustment				$ 400		$ 1,000
Tax benefit recognition period (in years)			15 years
Amount of goodwill expected to be tax deductible			$ 66,000	66,000
Payments to Acquire Businesses, Net of Cash Acquired				106,700
Amount of goodwill expected to not be tax deductible			$ 9,000	9,000
Schroth [Member]
Business Acquisition [Line Items]
Business acquisition cost		$ 89,700
Payments to Acquire Businesses, Net of Cash Acquired		79,700
Business Combination, Consideration Transferred, Liabilities Incurred		$ 9,000		$ 8,500
Schroth [Member]
Business Acquisition [Line Items]
Divestiture, Sale Price	$ 61,400

EARNINGS PER SHARE (TWO-CLASS37

EARNINGS PER SHARE (TWO-CLASS METHOD) - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Numerator for earnings per share:
INCOME FROM CONTINUING OPERATIONS	$ 201,840	$ 155,691	$ 513,851	$ 274,562
Less dividends paid on participating securities	0	0	(56,148)	(95,971)
Net Income Loss Attributable to Continuing Operations Available To Common Stockholders Basic And Vested Options Deemed Participating Securities	201,840	155,691	457,703	178,591
Loss from discontinued operations	(5,562)	(186)	(2,798)	(186)
Net income applicable to common stock - basic and diluted	$ 196,278	$ 155,505	$ 454,905	$ 178,405
Denominator for basic and diluted earnings per share under the two-class method, in shares:
Weighted average common shares outstanding	52,229	52,849	52,127	53,108
Vested options deemed participating securities	3,376	3,045	3,472	3,103
Basic and diluted (in shares)	55,605	55,894	55,599	56,211
Net earnings per share from continuing operations--basic and diluted	$ 3.63	$ 2.78	$ 8.23	$ 3.17
Net loss per share from discontinued operations--basic and diluted	(0.10)	0	(0.05)	0
Basic and diluted earnings per share (in dollars per share)	$ 3.53	$ 2.78	$ 8.18	$ 3.17

INVENTORIES - Schedule of Inven

INVENTORIES - Schedule of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Inventory Disclosure [Abstract]
Raw materials and purchased component parts	$ 517,910	$ 496,899
Work-in-progress	204,940	187,009
Finished goods	134,762	131,548
Total	857,612	815,456
Reserves for excess and obsolete inventory	(90,380)	(84,775)
Inventories - Net	$ 767,232	$ 730,681

INTANGIBLE ASSETS - Intangible

INTANGIBLE ASSETS - Intangible Assets Subject to Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 2,106,863	$ 2,115,249
Intangible Assets, Accumulated Amortization	406,454	397,387
Total	1,700,409	1,717,862
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,292,753	1,292,719
Accumulated Amortization	383,509	351,638
Net	909,244	941,081
Order backlog
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,700	29,000
Accumulated Amortization	2,252	26,668
Net	6,448	2,332
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	63,382	63,599
Accumulated Amortization	20,693	19,081
Net	42,689	44,518
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill), Gross	742,028	729,931
Indefinite-Lived Intangible Assets, Accumulated Amortization	0	0
Intangible Assets (Excluding Goodwill), Net	$ 742,028	$ 729,931

INTANGIBLE ASSETS - Summary of

INTANGIBLE ASSETS - Summary of changes in carrying value of Goodwill (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2018USD ($)
Goodwill [Line Items]
Goodwill, Acquired During Period	$ 2,218
Goodwill [Roll Forward]
Balance at beginning of period	5,745,338
Purchase price allocation adjustments	4,508
Goodwill, Foreign Currency Translation Gain (Loss)	6,645
Currency translation adjustment	(4)
Balance at end of period	5,758,705
Power & Control
Goodwill [Line Items]
Goodwill, Acquired During Period	0
Goodwill [Roll Forward]
Balance at beginning of period	3,269,981
Purchase price allocation adjustments	4,508
Goodwill, Foreign Currency Translation Gain (Loss)	0
Currency translation adjustment	(191)
Balance at end of period	3,274,298
Airframe
Goodwill [Line Items]
Goodwill, Acquired During Period	2,218
Goodwill [Roll Forward]
Balance at beginning of period	2,382,082
Purchase price allocation adjustments	0
Goodwill, Foreign Currency Translation Gain (Loss)	6,645
Currency translation adjustment	187
Balance at end of period	2,391,132
Non- aviation
Goodwill [Line Items]
Goodwill, Acquired During Period	0
Goodwill [Roll Forward]
Balance at beginning of period	93,275
Purchase price allocation adjustments	0
Goodwill, Foreign Currency Translation Gain (Loss)	0
Currency translation adjustment	0
Balance at end of period	$ 93,275

INTANGIBLE ASSETS - Narratives

INTANGIBLE ASSETS - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 17,457	$ 22,032	$ 34,569	$ 47,563
Estimated Amortization Expense, 2017	71,900		71,900
Estimated Amortization Expense, 2018	70,200		70,200
Estimated Amortization Expense, 2019	67,200		67,200
Estimated Amortization Expense, 2020	67,200		67,200
Estimated Amortization Expense, 2021	67,200		67,200
Estimated Amortization Expense, 2022	$ 67,200		$ 67,200

INTANGIBLE ASSETS - Acquired In

INTANGIBLE ASSETS - Acquired Intangibles (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2018USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period	$ 2,218
Indefinite-lived Intangible Assets Acquired	12,218
Finite-lived Intangible Assets Acquired	$ 8,000
Finite-Lived Intangible Asset, Useful Life	5 years 9 months 18 days
Intangible Assets, Acquired During the Period	$ 20,218
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 2,000
Finite-Lived Intangible Asset, Useful Life	20 years
Order backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 6,000
Finite-Lived Intangible Asset, Useful Life	1 year
Goodwill [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period	$ 2,218
Trademarks and trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets Acquired	$ 10,000

DEBT - Schedule of Debt (Detail

DEBT - Schedule of Debt (Detail) - USD ($) $ in Thousands		Mar. 31, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Gross Amount		$ 11,538,145	$ 11,573,009
Debt Issuance Costs		(88,896)	(95,169)
Original Issue Discount or Premium		(14,312)	(14,766)
Short-term borrowings - trade receivable securitization facility		299,833	299,587
Total debt outstanding		11,434,937	11,463,074
Long-term Debt, Current Maturities, Net		69,147	69,454
Long-term Debt, Excluding Current Maturities, Gross		11,468,460	11,502,978
Deferred Finance Costs, Excluding Current Maturities		(88,358)	(94,592)
Debt Instrument, Unamortized Discount, Excluding Current Maturities		(14,312)	(14,766)
Long-term debt		11,365,790	11,393,620
Term loans
Debt Instrument [Line Items]
Gross Amount		6,938,145	6,973,009
Debt Issuance Costs		(60,435)	(64,104)
Original Issue Discount or Premium		(18,221)	(18,948)
Total debt outstanding	[1]	$ 6,859,489	$ 6,889,957
Senior Subordinated Notes | 5 1/2% senior subordinated notes due 2020 (2020 Notes)
Debt Instrument [Line Items]
Interest rate		5.50%	5.50%
Gross Amount		$ 550,000	$ 550,000
Debt Issuance Costs		(2,715)	(3,243)
Original Issue Discount or Premium		0	0
Total debt outstanding	[1]	$ 547,285	$ 546,757
Senior Subordinated Notes | 6% senior subordinated notes due 2022 (2022 Notes)
Debt Instrument [Line Items]
Interest rate		6.00%	6.00%
Gross Amount		$ 1,150,000	$ 1,150,000
Debt Issuance Costs		(6,221)	(6,941)
Original Issue Discount or Premium		0	0
Total debt outstanding	[1]	$ 1,143,779	$ 1,143,059
Senior Subordinated Notes | 6 1/2% senior subordinated notes due 2024 (2024 Notes)
Debt Instrument [Line Items]
Interest rate		6.50%	6.50%
Gross Amount		$ 1,200,000	$ 1,200,000
Debt Issuance Costs		(7,454)	(8,042)
Original Issue Discount or Premium		0	0
Total debt outstanding	[1]	$ 1,192,546	$ 1,191,958
Senior Subordinated Notes | 6 1/2% senior subordinated notes due 2025 (2025 Notes)
Debt Instrument [Line Items]
Interest rate		6.50%	6.50%
Gross Amount		$ 750,000	$ 750,000
Debt Issuance Costs		(3,769)	(4,033)
Debt Instrument, Unamortized Premium		3,909	4,182
Total debt outstanding	[1]	$ 750,140	$ 750,149
Senior Subordinated Notes | 6 3/8% senior subordinated notes due 2026 (2026 Notes)
Debt Instrument [Line Items]
Interest rate		6.375%	6.375%
Gross Amount		$ 950,000	$ 950,000
Debt Issuance Costs		(8,302)	(8,806)
Original Issue Discount or Premium		0	0
Total debt outstanding	[1]	941,698	941,194
Asset-backed Securities
Debt Instrument [Line Items]
Short-term borrowings—trade receivable securitization facility, Gross		300,000	300,000
Debt Issuance Costs		(167)	(413)
Original Issue Discount or Premium		0	0
Short-term borrowings - trade receivable securitization facility	[1]	299,833	299,587
Less current portion
Debt Instrument [Line Items]
Debt Issuance Costs		(538)	(577)
Original Issue Discount or Premium		0	0
Long-term Debt, Current Maturities, Gross		69,685	70,031
Long-term Debt, Current Maturities, Net		$ 69,147	$ 69,454
[1]	The carrying amount of the debt instrument is presented net of the debt issuance costs. Refer to Note 8, "Debt," for gross carrying amounts.

DEBT - Narratives (Details)

DEBT - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2017
Debt Instrument [Line Items]
Interest Payable, Current	$ 83,100		$ 83,100		$ 82,200
Refinancing Costs	638	$ 3,507	1,751	$ 35,591
Fourth Amendment to Second Amended And Restated Credit Agreement [Member] | Fourth Amendment to Second Amended And Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Refinancing Costs			700
Debt Issuance Costs, Gross	2,900		2,900
Senior Subordinated Notes | 7 1/2% senior subordinated notes due 2021 (2021 Notes)
Debt Instrument [Line Items]
Write off of Deferred Debt Issuance Cost			500
Term loans | Existing Tranche D amount Converted to Tranche F [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	798,000		$ 798,000
Term loans | Tranche E and Tranche F [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate			2.75%
Term loans | Tranche F
Debt Instrument [Line Items]
Write off of Deferred Debt Issuance Cost			$ 200
Term loans | New Tranche G Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 1,809,000		$ 1,809,000
Term loans | Tranche G [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate			2.50%

INCOME TAXES - Narratives (Deta

INCOME TAXES - Narratives (Details) - USD ($) $ in Millions	Jan. 01, 2018	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2018	Sep. 30, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				35.00%
Effective income tax rate		18.30%	27.70%	(17.30%)	22.50%
Unrecognized tax benefits		$ 8.8		$ 8.8			$ 8.7
Tax rate effect		8.7		8.7			$ 8.7
Reduction in tax position in next 12 months		$ 0.6		0.6
U.S. Tax Cuts and Jobs Act Effective 2018 [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Deferred Federal Income Tax Expense (Benefit)				170.2
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount				23.1
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount				$ 147.1
U.S. Tax Cuts and Jobs Act Effective 2018 [Member] | Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent						24.50%

FAIR VALUE MEASUREMENTS - Carry

FAIR VALUE MEASUREMENTS - Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands		Mar. 31, 2018	Sep. 30, 2017		Apr. 01, 2017	Dec. 31, 2016	Sep. 30, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		$ 1,011,007	$ 650,561		$ 985,389	$ 985,389	$ 1,586,994
Short-term borrowings - trade receivable securitization facility		299,833	299,587
Long-term Debt		11,434,937	11,463,074
Other Noncurrent Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Cash Flow Hedge Asset at Carrying Value	[1]	27,343	12,904
Interest rate cap agreements	[1]	41,719	2,905
Prepaid Expenses and Other Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate cap agreements	[2]	2,507	0
Accrued Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements	[3]	1,533	20,740
Other Noncurrent Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements	[4]	54	9,731
Term loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[5]	6,859,489	6,889,957
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, Fair Value		1,011,007	650,561
Level 2 | Other Noncurrent Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate cap agreements, Fair Value	[1]	27,343	12,904
Interest Rate Swap Asset at Fair Value	[1]	41,719	2,905
Level 2 | Prepaid Expenses and Other Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Swap Asset at Fair Value	[2]	2,507	0
Level 2 | Accrued Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements, Fair Value	[3]	1,533	20,740
Level 2 | Other Noncurrent Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements, Fair Value	[4]	54	9,731
Level 2 | Term loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion, Fair Value		6,935,358	6,965,628
5 1/2% senior subordinated notes due 2020 (2020 Notes) | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[5]	547,285	546,757
5 1/2% senior subordinated notes due 2020 (2020 Notes) | Level 1 | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion, Fair Value		552,750	558,250
6% senior subordinated notes due 2022 (2022 Notes) | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[5]	1,143,779	1,143,059
6% senior subordinated notes due 2022 (2022 Notes) | Level 1 | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion, Fair Value		1,173,000	1,178,750
6 1/2% senior subordinated notes due 2024 (2024 Notes) | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[5]	1,192,546	1,191,958
6 1/2% senior subordinated notes due 2024 (2024 Notes) | Level 1 | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion, Fair Value		1,230,000	1,236,000
6 1/2% senior subordinated notes due 2025 (2025 Notes) | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[5]	750,140	750,149
6 1/2% senior subordinated notes due 2025 (2025 Notes) | Level 1 | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion, Fair Value		765,218	776,807
6 3/8% senior subordinated notes due 2026 (2026 Notes) | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[5]	941,698	941,194
6 3/8% senior subordinated notes due 2026 (2026 Notes) | Level 1 | Senior Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion, Fair Value		954,750	971,375
Asset-backed Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings - trade receivable securitization facility	[5]	299,833	299,587
Asset-backed Securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings - trade receivable securitization facility, Fair Value		$ 299,833	$ 299,587	[5]
[1]	Included in other non-current assets on the condensed consolidated balance sheet.
[2]	Included in prepaid expenses and other on the condensed consolidated balance sheet.
[3]	Included in accrued liabilities on the condensed consolidated balance sheet.
[4]	Included in other non-current liabilities on the condensed consolidated balance sheet.
[5]	The carrying amount of the debt instrument is presented net of the debt issuance costs. Refer to Note 8, "Debt," for gross carrying amounts.

DERIVATIVES AND HEDGING ACTIV47

DERIVATIVES AND HEDGING ACTIVITIES - Schedule of Notional Amounts of Outstanding Derivatives (Details) - USD ($)		6 Months Ended
		Mar. 31, 2018	Apr. 01, 2017
Tranche F | Interest rate cap beginning June 30, 2020 [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 750,000,000
Tranche F | Interest Rate Swap
Derivative [Line Items]
Derivative, Notional Amount		$ 500,000,000
Derivative, Fixed Interest Rate		4.65%
Derivative, Variable Interest Rate		1.90%
Derivative, Basis Spread on Variable Rate		2.75%
Tranche F | Interest rate swap June 28, 2016 [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 1,000,000,000
Derivative, Fixed Interest Rate		4.55%
Derivative, Variable Interest Rate		1.80%
Derivative, Basis Spread on Variable Rate		2.75%
Tranche F | Interest rate swap beginning March 31, 2016 [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 750,000,000
Derivative, Fixed Interest Rate		5.55%
Derivative, Variable Interest Rate		2.80%
Derivative, Basis Spread on Variable Rate		2.75%
Tranche F | Interest Rate Cap
Derivative [Line Items]
Derivative, Notional Amount		$ 400,000,000
Derivative, Cap Interest Rate		2.50%
Tranche F | Interest rate cap agreements beginning June 30, 2016 [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 400,000,000
Derivative, Cap Interest Rate		2.00%
Tranche F | Interest rate swap beginning June 30, 2020 [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 750,000,000
Derivative, Fixed Interest Rate		5.25%
Derivative, Variable Interest Rate		2.50%
Derivative, Basis Spread on Variable Rate		2.75%
Tranche E | Interest rate cap beginning September 30, 2015 [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 750,000,000
Derivative, Cap Interest Rate		2.50%
Tranche G [Member] | Interest Rate Swap
Derivative [Line Items]
Derivative, Notional Amount		$ 1,000,000,000
Derivative, Fixed Interest Rate		4.90%
Derivative, Variable Interest Rate		2.40%
Derivative, Basis Spread on Variable Rate		3.00%
Tranche G [Member] | Interest rate swap beginning September 30, 2017 [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 400,000,000
Derivative, Fixed Interest Rate		4.40%
Derivative, Variable Interest Rate		1.90%
Derivative, Basis Spread on Variable Rate		3.00%
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1) | Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative [Line Items]
Interest Expense	[1]	$ 2,213,000	$ 1,913,000
[1]	This component of accumulated other comprehensive (loss) income is included in interest expense (see Note 11, “Derivatives and Hedging Activities,” for additional information).

DERIVATIVES AND HEDGING ACTIV48

DERIVATIVES AND HEDGING ACTIVITIES - Schedule of Interest Rate Derivatives (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Sep. 30, 2017
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 73,947	$ 22,139
Derivative Asset, Fair Value, Gross Liability		(3,965)	(36,801)
Derivative Asset, Collateral, Obligation to Return Cash, Offset		(2,378)	(6,330)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		2,378	6,330
Derivative Asset	[1]	71,569	15,809
Derivative Liability	[1]	(1,587)	(30,471)
Interest Rate Cap
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		27,343	12,904
Derivative Asset, Fair Value, Gross Liability		0	0
Interest Rate Swap
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		46,604	9,235
Derivative Asset, Fair Value, Gross Liability		$ (3,965)	$ (36,801)
[1]	Refer to Note 10, "Fair Value Measurements," for the condensed consolidated balance sheet classification of our interest rate swap and cap agreements.

DERIVATIVES AND HEDGING ACTIV49

DERIVATIVES AND HEDGING ACTIVITIES - Narratives (Details) - USD ($)		6 Months Ended
		Mar. 31, 2018	Apr. 01, 2017
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1) | Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative [Line Items]
Interest Expense	[1]	$ 2,213,000	$ 1,913,000
December 30, 2017 Redesignation [Member] | Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1) | Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative [Line Items]
Interest Expense		300,000
September 30, 2016 Redesignation [Member] | Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1) | Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative [Line Items]
Interest Expense		$ 2,000,000
Interest Rate Swap and Cap
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimate of Time to Transfer		12 months
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred		$ 2,100,000
Interest Rate Cap
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Gross Amount to be Transferred		8,900,000
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Tax to be Transferred		2,400,000
Interest Rate Cap | Tranche F
Derivative [Line Items]
Derivative, Notional Amount		$ 400,000,000
Derivative, Cap Interest Rate		2.50%
Interest rate swap beginning June 30, 2020 [Member] | Tranche F
Derivative [Line Items]
Derivative, Notional Amount		$ 750,000,000
Derivative, Fixed Interest Rate		5.25%
Derivative, Variable Interest Rate		2.50%
Derivative, Basis Spread on Variable Rate		2.75%
Interest rate cap beginning September 30, 2015 [Member] | Tranche E
Derivative [Line Items]
Derivative, Notional Amount		$ 750,000,000
Derivative, Cap Interest Rate		2.50%
Interest rate cap agreements beginning June 30, 2016 [Member] | Tranche F
Derivative [Line Items]
Derivative, Notional Amount		$ 400,000,000
Derivative, Cap Interest Rate		2.00%
Interest Rate Swap | Tranche F
Derivative [Line Items]
Derivative, Notional Amount		$ 500,000,000
Derivative, Fixed Interest Rate		4.65%
Derivative, Variable Interest Rate		1.90%
Derivative, Basis Spread on Variable Rate		2.75%
Interest Rate Swap | March 31, 2018 Redesignation [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Gross Amount to be Transferred		$ 12,800,000
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Tax to be Transferred		3,100,000
Interest rate swap June 28, 2016 [Member] | Tranche F
Derivative [Line Items]
Derivative, Notional Amount		$ 1,000,000,000
Derivative, Fixed Interest Rate		4.55%
Derivative, Variable Interest Rate		1.80%
Derivative, Basis Spread on Variable Rate		2.75%
Interest rate swap beginning March 31, 2016 [Member] | Tranche F
Derivative [Line Items]
Derivative, Notional Amount		$ 750,000,000
Derivative, Fixed Interest Rate		5.55%
Derivative, Variable Interest Rate		2.80%
Derivative, Basis Spread on Variable Rate		2.75%
[1]	This component of accumulated other comprehensive (loss) income is included in interest expense (see Note 11, “Derivatives and Hedging Activities,” for additional information).

SEGMENTS - Narratives (Details)

SEGMENTS - Narratives (Details)	6 Months Ended
	Mar. 31, 2018Segment
Segment Reporting [Abstract]
Number of reporting segments	3

SEGMENTS - Net Sales by Reporta

SEGMENTS - Net Sales by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Segment Reporting Information [Line Items]
Net Sales	$ 933,070	$ 868,728	$ 1,781,030	$ 1,682,746
Operating Segments | Power & Control
Segment Reporting Information [Line Items]
Net Sales	528,460	473,952	1,011,178	909,784
Operating Segments | Airframe
Segment Reporting Information [Line Items]
Net Sales	369,783	360,509	703,175	709,173
Operating Segments | Non- aviation
Segment Reporting Information [Line Items]
Net Sales	$ 34,827	$ 34,267	$ 66,677	$ 63,789

SEGMENTS - EBITDA Defined by Se

SEGMENTS - EBITDA Defined by Segment to Consolidated Income Before Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
EBITDA As Defined	$ 463,123	$ 421,676	$ 864,656	$ 802,870
Interest expense - net	161,266	147,842	322,199	293,846
Stock compensation expense			22,703	21,126
Refinancing Costs	638	3,507	1,751	35,591
Income from continuing operations before income taxes	247,187	215,199	438,151	354,120
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
EBITDA As Defined	471,889	427,199	884,079	817,923
Operating Segments | Power & Control
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
EBITDA As Defined	275,562	232,828	520,337	445,746
Operating Segments | Airframe
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
EBITDA As Defined	186,006	182,980	344,425	351,509
Operating Segments | Non- aviation
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
EBITDA As Defined	10,321	11,391	19,317	20,668
Corporate, Non-Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
EBITDA As Defined	8,766	5,523	19,423	15,053
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization expense	30,970	34,661	61,609	72,708
Interest expense - net	161,266	147,842	322,199	293,846
Acquisition-related costs	4,485	7,752	6,559	26,320
Stock compensation expense	11,590	11,105	22,703	21,126
Refinancing Costs	638	3,507	1,751	35,591
Other, net	$ 6,987	$ 1,610	$ 11,684	$ (841)

SEGMENTS - Total Assets by Segm

SEGMENTS - Total Assets by Segment (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 10,394,677	$ 9,975,661
Operating Segments | Power & Control
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	5,177,803	5,135,459
Operating Segments | Airframe
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	4,021,406	3,923,172
Operating Segments | Non- aviation
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	226,005	224,936
Corporate, Non-Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	969,463	614,594
Discontinued Operations, Held-for-sale [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 0	$ 77,500

ACCUMULATED OTHER COMPREHENSI54

ACCUMULATED OTHER COMPREHENSIVE LOSS - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Loss, Derivatives Qualifying as Hedges, Tax	$ (14,290)	$ (1,310)	$ (24,725)	$ (24,427)

ACCUMULATED OTHER COMPREHENSI55

ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Accumulated Other Comprehensive Loss (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2018USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (85,143)
Current-period other comprehensive gain	90,015
Amounts reclassified from AOCI related to interest rate swap and cap agreements	1,647
Balance at end of period	6,519
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(26,669)	[1]
Current-period other comprehensive gain	61,827	[1]
Amounts reclassified from AOCI related to interest rate swap and cap agreements	(1,647)	[1]
Balance at end of period	36,805	[1]
Defined benefit pension plan activity
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(16,365)
Current-period other comprehensive gain	0
Amounts reclassified from AOCI related to interest rate swap and cap agreements	0
Balance at end of period	(16,365)
Currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(42,109)
Current-period other comprehensive gain	28,188
Amounts reclassified from AOCI related to interest rate swap and cap agreements	0
Balance at end of period	$ (13,921)
[1]	Unrealized gain represents interest rate swap and cap agreements, net of taxes of $(14,290) and $(1,310) for the thirteen week periods ended March 31, 2018 and April 1, 2017 and $(24,725) and $(24,427) for the twenty-six week periods ended March 31, 2018 and April 1, 2017, respectively.

ACCUMULATED OTHER COMPREHENSI56

ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Amounts Recognized in Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Deferred tax benefit from redesignated interest rate swap and cap agreements		$ 45,347	$ 59,508	$ (75,700)	$ 79,558
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (1) | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization from redesignated interest rate swap and cap agreements (1)	[1]			2,213	1,913
Deferred tax benefit from redesignated interest rate swap and cap agreements				(566)	(715)
Losses reclassified into earnings, net of tax				$ 1,647	$ 1,198
[1]	This component of accumulated other comprehensive (loss) income is included in interest expense (see Note 11, “Derivatives and Hedging Activities,” for additional information).

DISCONTINUED OPERATIONS Narrati

DISCONTINUED OPERATIONS Narrative (Details) - USD ($) $ in Thousands	Jan. 26, 2018	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations		$ (5,562)	$ (186)	$ (2,798)	$ (186)
Total assets of discontinued operations		0		0		$ 77,500
Total liabilities of discontinued operations		0		0		17,304
Discontinued Operations, Held-for-sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations		$ (5,562)	$ (186)	$ (2,798)	$ (186)
Schroth [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Divestiture, Sale Price	$ 61,400
Schroth [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill, Impairment Loss						$ 32,000

DISCONTINUED OPERATIONS Schedul

DISCONTINUED OPERATIONS Schedule of Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
NET SALES	$ 933,070	$ 868,728	$ 1,781,030	$ 1,682,746
Loss from discontinued operations	(5,562)	(186)	(2,798)	(186)
Trade accounts receivable - Net	644,985		644,985		$ 636,127
Inventories - Net	767,232		767,232		730,681
Prepaid expenses and other	46,880		46,880		38,683
PROPERTY, PLANT AND EQUIPMENT - NET	352,456		352,456		324,924
GOODWILL	5,758,705		5,758,705		5,745,338
OTHER INTANGIBLE ASSETS - NET	1,700,409		1,700,409		1,717,862
OTHER	113,003		113,003		53,985
Total assets of discontinued operations	0		0		77,500
Accounts payable	151,709		151,709		148,761
Accrued liabilities	292,146		292,146		335,888
DEFERRED INCOME TAXES	359,342		359,342		500,949
Total liabilities of discontinued operations	0		0		$ 17,304
Discontinued Operations, Held-for-sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
NET SALES	2,679	4,504	11,808	4,504
(Loss) income from discontinued operations before income taxes	(456)	(186)	354	(186)
(Loss) income from discontinued operations, net of tax	62	0	2,016	0
Income (loss) from discontinued operations before gain or loss on disposal net of tax	(394)	(186)	2,370	(186)
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	(5,168)	0	(5,168)	0
Loss from discontinued operations	$ (5,562)	$ (186)	$ (2,798)	$ (186)

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - USD ($) $ in Thousands	Apr. 24, 2018	Mar. 31, 2018	Apr. 01, 2017	May 01, 2018	Sep. 30, 2017
Subsequent Event [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 50,320	$ 30,002
Gross Amount		11,538,145			$ 11,573,009
Subsequent Event [Member]
Subsequent Event [Line Items]
Senior Notes				$ 500,000
Asset-backed Securities
Subsequent Event [Line Items]
Short-term borrowings—trade receivable securitization facility, Gross		$ 300,000			$ 300,000
Extant [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 525,000
Tranche E | Subsequent Event [Member]
Subsequent Event [Line Items]
Gross Amount				$ 700,000

SUPPLEMENTAL GUARANTOR INFORM60

SUPPLEMENTAL GUARANTOR INFORMATION - Supplemental Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017	Apr. 01, 2017	Dec. 31, 2016	Sep. 30, 2016
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	$ 1,011,007	$ 650,561	$ 985,389	$ 985,389	$ 1,586,994
Trade accounts receivable - Net	644,985	636,127
Inventories - Net	767,232	730,681
Total assets of discontinued operations	0	77,500
Prepaid expenses and other	46,880	38,683
Total current assets	2,470,104	2,133,552
INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES	0	0
PROPERTY, PLANT AND EQUIPMENT - NET	352,456	324,924
GOODWILL	5,758,705	5,745,338
OTHER INTANGIBLE ASSETS - NET	1,700,409	1,717,862
OTHER	113,003	53,985
TOTAL ASSETS	10,394,677	9,975,661
Current portion of long-term debt	69,147	69,454
Short-term borrowings - trade receivable securitization facility	299,833	299,587
Accounts payable	151,709	148,761
Accrued liabilities	292,146	335,888
Total liabilities of discontinued operations	0	17,304
Total current liabilities	812,835	870,994
LONG-TERM DEBT	11,365,790	11,393,620
DEFERRED INCOME TAXES	359,342	500,949
OTHER NON-CURRENT LIABILITIES	166,047	161,302
Total liabilities	12,704,014	12,926,865
STOCKHOLDERS’ (DEFICIT) EQUITY	(2,309,337)	(2,951,204)
TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY	10,394,677	9,975,661
Eliminations
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0	0		0	0
Trade accounts receivable - Net	(21,829)	(41,749)
Inventories - Net	(3,057)	(2,100)
Total assets of discontinued operations		0
Prepaid expenses and other	0	0
Total current assets	(24,886)	(43,849)
INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES	(18,897,354)	(15,876,264)
PROPERTY, PLANT AND EQUIPMENT - NET	0	0
GOODWILL	0	0
OTHER INTANGIBLE ASSETS - NET	0	0
OTHER	0	0
TOTAL ASSETS	(18,922,240)	(15,920,113)
Current portion of long-term debt	0	0
Short-term borrowings - trade receivable securitization facility	0	0
Accounts payable	(19,623)	(41,566)
Accrued liabilities	0	0
Total liabilities of discontinued operations		0
Total current liabilities	(19,623)	(41,566)
LONG-TERM DEBT	0	0
DEFERRED INCOME TAXES	0	0
OTHER NON-CURRENT LIABILITIES	0	0
Total liabilities	(19,623)	(41,566)
STOCKHOLDERS’ (DEFICIT) EQUITY	(18,902,617)	(15,878,547)
TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY	(18,922,240)	(15,920,113)
TransDigm Group
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	14,621	2,416		1,182	13,560
Trade accounts receivable - Net	0	0
Inventories - Net	0	0
Total assets of discontinued operations		0
Prepaid expenses and other	0	0
Total current assets	14,621	2,416
INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES	(2,323,958)	(2,953,620)
PROPERTY, PLANT AND EQUIPMENT - NET	0	0
GOODWILL	0	0
OTHER INTANGIBLE ASSETS - NET	0	0
OTHER	0	0
TOTAL ASSETS	(2,309,337)	(2,951,204)
Current portion of long-term debt	0	0
Short-term borrowings - trade receivable securitization facility	0	0
Accounts payable	0	0
Accrued liabilities	0	0
Total liabilities of discontinued operations		0
Total current liabilities	0	0
LONG-TERM DEBT	0	0
DEFERRED INCOME TAXES	0	0
OTHER NON-CURRENT LIABILITIES	0	0
Total liabilities	0	0
STOCKHOLDERS’ (DEFICIT) EQUITY	(2,309,337)	(2,951,204)
TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY	(2,309,337)	(2,951,204)
TransDigm Inc.
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	817,685	439,473		811,930	1,421,251
Trade accounts receivable - Net	0	0
Inventories - Net	46,100	47,051
Total assets of discontinued operations		0
Prepaid expenses and other	7,477	4,746
Total current assets	871,262	491,270
INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES	10,255,472	10,263,999
PROPERTY, PLANT AND EQUIPMENT - NET	15,611	16,032
GOODWILL	82,553	85,905
OTHER INTANGIBLE ASSETS - NET	26,907	27,620
OTHER	78,068	20,316
TOTAL ASSETS	11,329,873	10,905,142
Current portion of long-term debt	69,147	69,454
Short-term borrowings - trade receivable securitization facility	0	0
Accounts payable	16,951	14,712
Accrued liabilities	113,827	180,916
Total liabilities of discontinued operations		0
Total current liabilities	199,925	265,082
LONG-TERM DEBT	11,365,790	11,393,620
DEFERRED INCOME TAXES	300,255	442,415
OTHER NON-CURRENT LIABILITIES	68,538	61,347
Total liabilities	11,934,508	12,162,464
STOCKHOLDERS’ (DEFICIT) EQUITY	(604,635)	(1,257,322)
TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY	11,329,873	10,905,142
Subsidiary Guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	3,284	(203)		1,068	8,808
Trade accounts receivable - Net	13,998	25,069
Inventories - Net	603,775	571,712
Total assets of discontinued operations		6,428
Prepaid expenses and other	23,855	24,141
Total current assets	644,912	627,147
INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES	8,266,878	7,599,210
PROPERTY, PLANT AND EQUIPMENT - NET	286,939	261,434
GOODWILL	5,006,108	4,996,034
OTHER INTANGIBLE ASSETS - NET	1,422,511	1,438,006
OTHER	29,107	27,567
TOTAL ASSETS	15,656,455	14,949,398
Current portion of long-term debt	0	0
Short-term borrowings - trade receivable securitization facility	0	0
Accounts payable	116,868	137,948
Accrued liabilities	128,807	103,902
Total liabilities of discontinued operations		0
Total current liabilities	245,675	241,850
LONG-TERM DEBT	0	0
DEFERRED INCOME TAXES	113	(99)
OTHER NON-CURRENT LIABILITIES	69,243	73,245
Total liabilities	315,031	314,996
STOCKHOLDERS’ (DEFICIT) EQUITY	15,341,424	14,634,402
TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY	15,656,455	14,949,398
Non- Guarantor Subsidiaries
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	175,417	208,875		$ 171,209	$ 143,375
Trade accounts receivable - Net	652,816	652,807
Inventories - Net	120,414	114,018
Total assets of discontinued operations		71,072
Prepaid expenses and other	15,548	9,796
Total current assets	964,195	1,056,568
INVESTMENT IN SUBSIDIARIES AND INTERCOMPANY BALANCES	2,698,962	966,675
PROPERTY, PLANT AND EQUIPMENT - NET	49,906	47,458
GOODWILL	670,044	663,399
OTHER INTANGIBLE ASSETS - NET	250,991	252,236
OTHER	5,828	6,102
TOTAL ASSETS	4,639,926	2,992,438
Current portion of long-term debt	0	0
Short-term borrowings - trade receivable securitization facility	299,833	299,587
Accounts payable	37,513	37,667
Accrued liabilities	49,512	51,070
Total liabilities of discontinued operations		17,304
Total current liabilities	386,858	405,628
LONG-TERM DEBT	0	0
DEFERRED INCOME TAXES	58,974	58,633
OTHER NON-CURRENT LIABILITIES	28,266	26,710
Total liabilities	474,098	490,971
STOCKHOLDERS’ (DEFICIT) EQUITY	4,165,828	2,501,467
TOTAL LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY	$ 4,639,926	$ 2,992,438

SUPPLEMENTAL GUARANTOR INFORM61

SUPPLEMENTAL GUARANTOR INFORMATION - Supplemental Condensed Consolidating Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Condensed Income Statements, Captions [Line Items]
NET SALES	$ 933,070	$ 868,728	$ 1,781,030	$ 1,682,746
COST OF SALES	398,996	379,291	770,306	749,054
GROSS PROFIT	534,074	489,437	1,010,724	933,692
SELLING AND ADMINISTRATIVE EXPENSES	107,526	100,857	214,054	202,572
AMORTIZATION OF INTANGIBLE ASSETS	17,457	22,032	34,569	47,563
(LOSS) INCOME FROM OPERATIONS	409,091	366,548	762,101	683,557
INTEREST EXPENSE - NET	161,266	147,842	322,199	293,846
REFINANCING COSTS	638	3,507	1,751	35,591
EQUITY IN INCOME OF SUBSIDIARIES			0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	247,187	215,199	438,151	354,120
INCOME TAX PROVISION	45,347	59,508	(75,700)	79,558
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	201,840	155,691	513,851	274,562
Loss from discontinued operations	(5,562)	(186)	(2,798)	(186)
NET INCOME	196,278	155,505	511,053	274,376
OTHER COMPREHENSIVE INCOME, NET OF TAX	68,262	10,229	91,662	20,952
TOTAL COMPREHENSIVE INCOME	$ 264,540	$ 165,734	602,715	295,328
Eliminations
Condensed Income Statements, Captions [Line Items]
NET SALES			(39,412)	(40,597)
COST OF SALES			(39,412)	(40,597)
GROSS PROFIT			0	0
SELLING AND ADMINISTRATIVE EXPENSES			0	0
AMORTIZATION OF INTANGIBLE ASSETS			0	0
(LOSS) INCOME FROM OPERATIONS			0	0
INTEREST EXPENSE - NET			0	0
REFINANCING COSTS			0	0
EQUITY IN INCOME OF SUBSIDIARIES			1,073,597	904,158
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES			(1,073,597)	(904,158)
INCOME TAX PROVISION			0	0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent			(1,073,597)	(904,158)
Loss from discontinued operations			0
NET INCOME			(1,073,597)	(904,158)
OTHER COMPREHENSIVE INCOME, NET OF TAX			(129,559)	3,357
TOTAL COMPREHENSIVE INCOME			(1,203,156)	(900,801)
TransDigm Group
Condensed Income Statements, Captions [Line Items]
NET SALES			0	0
COST OF SALES			0	0
GROSS PROFIT			0	0
SELLING AND ADMINISTRATIVE EXPENSES			0	61
AMORTIZATION OF INTANGIBLE ASSETS			0	0
(LOSS) INCOME FROM OPERATIONS			0	(61)
INTEREST EXPENSE - NET			0	0
REFINANCING COSTS			0	0
EQUITY IN INCOME OF SUBSIDIARIES			(511,053)	(274,437)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES			511,053	274,376
INCOME TAX PROVISION			0	0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent			511,053	274,376
Loss from discontinued operations			0	0
NET INCOME			511,053	274,376
OTHER COMPREHENSIVE INCOME, NET OF TAX			91,662	20,952
TOTAL COMPREHENSIVE INCOME			602,715	295,328
TransDigm Inc.
Condensed Income Statements, Captions [Line Items]
NET SALES			77,215	65,037
COST OF SALES			43,858	36,230
GROSS PROFIT			33,357	28,807
SELLING AND ADMINISTRATIVE EXPENSES			48,893	47,474
AMORTIZATION OF INTANGIBLE ASSETS			714	387
(LOSS) INCOME FROM OPERATIONS			(16,250)	(19,054)
INTEREST EXPENSE - NET			318,138	298,005
REFINANCING COSTS			1,751	35,591
EQUITY IN INCOME OF SUBSIDIARIES			(562,544)	(629,721)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES			226,405	277,071
INCOME TAX PROVISION			(284,648)	2,634
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent			511,053	274,437
Loss from discontinued operations			0	0
NET INCOME			511,053	274,437
OTHER COMPREHENSIVE INCOME, NET OF TAX			64,166	40,955
TOTAL COMPREHENSIVE INCOME			575,219	315,392
Subsidiary Guarantors
Condensed Income Statements, Captions [Line Items]
NET SALES			1,441,477	1,409,050
COST OF SALES			577,494	605,288
GROSS PROFIT			863,983	803,762
SELLING AND ADMINISTRATIVE EXPENSES			103,779	127,391
AMORTIZATION OF INTANGIBLE ASSETS			29,709	43,108
(LOSS) INCOME FROM OPERATIONS			730,495	633,263
INTEREST EXPENSE - NET			(2)	(31)
REFINANCING COSTS			0	0
EQUITY IN INCOME OF SUBSIDIARIES			0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES			730,497	633,294
INCOME TAX PROVISION			202,265	73,549
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent			528,232	559,745
Loss from discontinued operations			(17,869)	(423)
NET INCOME			510,363	559,322
OTHER COMPREHENSIVE INCOME, NET OF TAX			9,719	15,012
TOTAL COMPREHENSIVE INCOME			520,082	574,334
Non- Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
NET SALES			301,750	249,256
COST OF SALES			188,366	148,133
GROSS PROFIT			113,384	101,123
SELLING AND ADMINISTRATIVE EXPENSES			61,382	27,646
AMORTIZATION OF INTANGIBLE ASSETS			4,146	4,068
(LOSS) INCOME FROM OPERATIONS			47,856	69,409
INTEREST EXPENSE - NET			4,063	(4,128)
REFINANCING COSTS			0	0
EQUITY IN INCOME OF SUBSIDIARIES			0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES			43,793	73,537
INCOME TAX PROVISION			6,683	3,375
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent			37,110	70,162
Loss from discontinued operations			15,071	237
NET INCOME			52,181	70,399
OTHER COMPREHENSIVE INCOME, NET OF TAX			55,674	(59,324)
TOTAL COMPREHENSIVE INCOME			$ 107,855	$ 11,075

SUPPLEMENTAL GUARANTOR INFORM62

SUPPLEMENTAL GUARANTOR INFORMATION - Supplemental Condensed Consolidating Cash Flow Statement (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2017
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$ 453,684	$ 390,500
Capital expenditures	(30,884)	(38,436)
Payments made in connection with acquisitions	(50,320)	(30,002)
Proceeds (payments made) from sale (purchase) of discontinued operations	57,686	(78,879)
Net cash provided by (used in) investing activities	(23,518)	(147,317)
Intercompany activities	0	0
Proceeds from exercise of stock options	26,305	12,345
Special dividend and dividend equivalent payments	(56,148)	(1,375,998)
Treasury stock purchased	0	339,833
Proceeds from term loans, net	793,042	1,132,774
Repayment on term loans	(833,052)	(32,302)
Proceeds from Issuance of Subordinated Long-term Debt		301,006
Cash tender and redemption of senior subordinated notes due 2021, including premium	0	(528,847)
Other	(2,155)	(10,745)
Net cash provided by (used in) financing activities	(72,008)	(841,600)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	2,288	(3,188)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	360,446	(601,605)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	650,561	1,586,994	$ 1,586,994
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,011,007	985,389	650,561
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	2,980	1,116
Capital expenditures	0	0
Payments made in connection with acquisitions	0
Proceeds (payments made) from sale (purchase) of discontinued operations	0	0
Net cash provided by (used in) investing activities	0	0
Intercompany activities	(2,980)	(1,116)
Proceeds from exercise of stock options	0	0
Special dividend and dividend equivalent payments	0	0
Treasury stock purchased		0
Proceeds from term loans, net	0	0
Repayment on term loans	0	0
Proceeds from Issuance of Subordinated Long-term Debt		0
Cash tender and redemption of senior subordinated notes due 2021, including premium		0
Other	0	0
Net cash provided by (used in) financing activities	(2,980)	(1,116)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	0	0
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0		0
TransDigm Group
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	0	(61)
Capital expenditures	0
Payments made in connection with acquisitions	0
Proceeds (payments made) from sale (purchase) of discontinued operations	0	0
Net cash provided by (used in) investing activities	0	0
Intercompany activities	42,048	1,691,169
Proceeds from exercise of stock options	26,305	12,345
Special dividend and dividend equivalent payments	(56,148)	(1,375,998)
Treasury stock purchased		339,833
Proceeds from term loans, net	0	0
Repayment on term loans	0	0
Proceeds from Issuance of Subordinated Long-term Debt		0
Cash tender and redemption of senior subordinated notes due 2021, including premium		0
Other	0	0
Net cash provided by (used in) financing activities	12,205	(12,317)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	0	0
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	12,205	(12,378)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	2,416	13,560	13,560
CASH AND CASH EQUIVALENTS, END OF PERIOD	14,621		2,416
TransDigm Inc.
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	(157,892)	(332,771)
Capital expenditures	(826)	(829)
Payments made in connection with acquisitions	(50,320)	(30,002)
Proceeds (payments made) from sale (purchase) of discontinued operations	57,686	(78,879)
Net cash provided by (used in) investing activities	6,540	(109,710)
Intercompany activities	571,729	(1,028,726)
Proceeds from exercise of stock options	0	0
Special dividend and dividend equivalent payments	0	0
Treasury stock purchased		0
Proceeds from term loans, net	793,042	1,132,774
Repayment on term loans	(833,052)	(32,302)
Proceeds from Issuance of Subordinated Long-term Debt		301,006
Cash tender and redemption of senior subordinated notes due 2021, including premium		(528,847)
Other	(2,155)	(10,745)
Net cash provided by (used in) financing activities	529,564	(166,840)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	0	0
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	378,212	(609,321)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	439,473	1,421,251	1,421,251
CASH AND CASH EQUIVALENTS, END OF PERIOD	817,685		439,473
Subsidiary Guarantors
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	578,789	720,181
Capital expenditures	(27,370)	(34,576)
Payments made in connection with acquisitions	0
Proceeds (payments made) from sale (purchase) of discontinued operations	0	0
Net cash provided by (used in) investing activities	(27,370)	(34,576)
Intercompany activities	(547,932)	(693,345)
Proceeds from exercise of stock options	0	0
Special dividend and dividend equivalent payments	0	0
Treasury stock purchased		0
Proceeds from term loans, net	0	0
Repayment on term loans	0	0
Proceeds from Issuance of Subordinated Long-term Debt		0
Cash tender and redemption of senior subordinated notes due 2021, including premium		0
Other	0	0
Net cash provided by (used in) financing activities	(547,932)	(693,345)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	0	0
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	3,487	(7,740)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	(203)	8,808	8,808
CASH AND CASH EQUIVALENTS, END OF PERIOD	3,284		(203)
Non- Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	29,807	2,035
Capital expenditures	(2,688)	(3,031)
Payments made in connection with acquisitions	0
Proceeds (payments made) from sale (purchase) of discontinued operations	0	0
Net cash provided by (used in) investing activities	(2,688)	(3,031)
Intercompany activities	(62,865)	32,018
Proceeds from exercise of stock options	0	0
Special dividend and dividend equivalent payments	0	0
Treasury stock purchased		0
Proceeds from term loans, net	0	0
Repayment on term loans	0	0
Proceeds from Issuance of Subordinated Long-term Debt		0
Cash tender and redemption of senior subordinated notes due 2021, including premium		0
Other	0	0
Net cash provided by (used in) financing activities	(62,865)	32,018
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	2,288	(3,188)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(33,458)	27,834
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	208,875	$ 143,375	143,375
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 175,417		$ 208,875

SUPPLEMENTAL GUARANTOR INFORM63

SUPPLEMENTAL GUARANTOR INFORMATION Narrative (Details)	Mar. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Percentage of ownership in subsidiary	100.00%