Exhibit 5.1

                                    [Letterhead]

                                 April 23, 1999






                                                         (File No.) 027584-0001



TransDigm Inc.
TransDigm Holding Company
Marathon Power Technologies Company
ZMP, Inc.
Adams Rite Aerospace, Inc.
8233 Imperial Drive
Waco, Texas 76712



              Re:    Registration Statement on Form S-4
                     TransDigm Inc.
                     TransDigm Holding Company
                     Marathon Power Technologies Company
                     ZMP, Inc.
                     Adams Rite Aerospace, Inc.
                     FILE NO. 333-71397


Ladies and Gentlemen:


          In connection with the registration of $125,000,000 in aggregate
principal amount of 10-3/8% Senior Subordinated Notes due 2008 (the "New Notes")
by TransDigm Inc., a Delaware corporation (the "Company"), and the guarantees of
the New Notes (the "New Guarantees") by each of TransDigm Holding Company, a
Delaware corporation ("Holdings"), Marathon Power Technologies Company, a
Delaware corporation ("Marathon"), ZMP, Inc., a 




Latham & Watkins
       TransDigm Inc.
       TransDigm Holding Company
       Marathon Power Technologies Company
       ZMP, Inc.
       Adams Rite Aerospace, Inc.
       April 23, 1999
       Page 2

California corporation ("ZMP"), and Adams Rite Aerospace, Inc., a California 
corporation ("Adams Rite Aerospace" and, together with Holdings, Marathon and 
ZMP, the "Guarantors"), in each case, under the Securities Act of 1933, as 
amended (the "Act"), on Form S-4 filed with the Securities and Exchange 
Commission (the "Commission") on January 29, 1999 (File No. 333-50219), as 
the same has been amended on or prior to the date hereof, and as it may be 
further amended (collectively the "Registration Statement"), you have 
requested our opinion with respect to the matters set forth below. The New 
Notes and the New Guarantees will be issued pursuant to an indenture, dated 
as of December 3, 1998, among the Company, Holdings and Marathon and State 
Street Bank and Trust Company, as trustee (the "Trustee"), as supplemented by 
a supplemental indenture, dated April 23, 1999, among the Company, the 
Guarantors and the Trustee (such indenture, as supplemented by such 
supplemental indenture, the "Indenture"). The New Notes and the New 
Guarantees will be issued in exchange for the Company's outstanding 10-3/8% 
Senior Subordinated Notes due 2008 (the "Old Notes") and the guarantees of 
the Old Notes by the Guarantors (the "Old Guarantees") on the terms set forth 
in the prospectus contained in the Registration Statement and the Letter of 
Transmittal filed as an exhibit thereto (the "Exchange Offer").

          In our capacity as your special counsel, we are familiar with the
proceedings taken and proposed to be taken by the Company and the Guarantors in
connection with the authorization and issuance of the New Notes and the New
Guarantees, respectively, and for the purposes of this opinion, have assumed
such proceedings will be timely completed in the manner currently proposed. In
addition, we have made such legal and factual examinations and inquiries,
including an examination of originals or copies certified or otherwise
identified to our satisfaction of such documents, corporate records and
instruments, as we have deemed necessary or appropriate for purposes of this
opinion.

          In our examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals and the
conformity to authentic original documents of all documents submitted to us as
copies. As to facts material to the opinions, statements and assumptions
expressed herein, we have, with your consent, relied upon oral or written
statements and representations of officers and other representatives of the
Company, the Guarantors and others.

          We are opining herein as to the effect on the subject transaction only
of the federal laws of the United States, the internal laws of the States of New
York and California and the General Corporation Law of the State of Delaware,
and we express no opinion with respect to the applicability thereto, or the
effect thereon, of the laws of any other jurisdiction or, in the case of



Latham & Watkins
       TransDigm Inc.
       TransDigm Holding Company
       Marathon Power Technologies Company
       ZMP, Inc.
       Adams Rite Aerospace, Inc.
       April 23, 1999
       Page 3

Delaware, any other laws, or as to any matters of municipal law or the laws of
any other local agencies within any state.

          Subject to the foregoing and the other matters set forth herein, it is
our opinion that, as of the date hereof:

          (1) The New Notes to be exchanged for the Old Notes pursuant to the
Exchange Offer have been duly authorized by all necessary corporate action on
the part of the Company, and, when duly executed, issued and authenticated in
accordance with the terms of the Exchange Offer and the Indenture and exchanged
for the Old Notes in accordance with the terms of the Exchange Offer, will be
the legally valid and binding obligations of the Company, enforceable against
the Company in accordance with their terms.

          (2) Each of the New Guarantees has been duly authorized by all
necessary corporate action on the part of the Guarantors, and, when duly
executed and endorsed on the New Notes in accordance with the terms of the
Indenture and upon the due execution, issuance and authentication of the New
Notes in accordance with the terms of the Exchange Offer and the Indenture and
exchange of the New Notes for the Old Notes in accordance with the terms of the
Exchange Offer, will be the legally valid and binding obligation of each of the
Guarantors, enforceable against each of the Guarantors in accordance with its
terms.

          The opinions rendered in paragraphs 1 and 2 relating to the
enforceability of the New Notes and the New Guarantees are subject to the
following exceptions, limitations and qualifications: (i) the effect of
bankruptcy, insolvency, reorganization, moratorium or other similar laws now or
hereafter in effect relating to or affecting the rights and remedies of
creditors; (ii) the effect of general principles of equity, whether enforcement
is considered in a proceeding in equity or at law, and the discretion of the
court before which any proceeding therefor may be brought and (iii) we express
no opinion concerning the enforceability of the waiver of rights or defenses
contained in Section 4.06 of the Indenture.

          To the extent that the obligations of the Company or any of the
Guarantors under the Indenture, the New Notes or the New Guarantees may be
dependent upon such matters, we have assumed for purposes of this opinion that
(i) the Trustee (a) is duly organized, validly existing and in good standing
under the laws of its jurisdiction of organization; (b) has the requisite
organizational and legal power and authority to perform its obligations under
the Indenture; (c) is duly qualified to engage in the activities contemplated by
the Indenture; (d) has duly authorized, executed and delivered the Indenture and
(e) has complied with any applicable requirement to file returns and pay taxes
under the Franchise Tax Law of the State of California; (ii) the Indenture is
the legally valid and binding agreement of the Trustee, enforceable against 



Latham & Watkins
       TransDigm Inc.
       TransDigm Holding Company
       Marathon Power Technologies Company
       ZMP, Inc.
       Adams Rite Aerospace, Inc.
       April 23, 1999
       Page 4


the Trustee in accordance with its terms; and (iii) that the Trustee is in
compliance, generally and with respect to acting as Trustee under the Indenture,
with all applicable laws and regulations. We have also assumed, with your
consent, that the choice of law provisions in the Indenture would be enforced by
any court in which enforcement thereof might be sought.

          We have not been requested to express and, with your knowledge and
consent, do not render any opinion as to the applicability to the obligations of
the Company and the Guarantors under the Indenture, the New Notes and the New
Guarantees, as applicable, of Sections 547 and 548 of the Bankruptcy Code or
applicable state law (including, without limitation, Article 10 of the New York
Debtor & Creditor Law) relating to preferences and fraudulent transfers and
obligations.

          We consent to your filing this opinion as an exhibit to the
Registration Statement and to the reference to our firm contained under the
heading "Legal Matters."

                                      Very truly yours,

                                      /s/ Latham & Watkins