FIRST AMENDMENT TO STOCK SALE AND PURCHASE AGREEMENT This First Amendment (the "First Amendment") to that certain STOCK SALE AND PURCHASE AGREEMENT (the "Agreement") dated June _____, 2010 (the "Execution Date") by and between (a) (i) Clayton I. Gamber, Kenneth W. Langston and Robin V. Gamber (each of the foregoing persons is referred to hereinafter as a "Seller" and collectively as the "Sellers"), each of whom is a shareholder of Twin Air Calypso Limited, Inc. (the "Company"), a Florida corporation, on the one hand, and (b) AvStar Aviation Group, Inc., a Colorado corporation ("Purchaser"), on the other hand. All capitalized, undefined terms used herein shall have the respective meanings given to such terms in the Agreement. RECITALS WHEREAS, the Agreement was entered on or about the Execution Date; and WHEREAS, each of the Sellers and Purchaser desire to amend the Agreement upon the terms, provisions and conditions set forth hereinafter; AGREEMENT NOW, THEREFORE, in consideration of the mutual covenants and agreements of the Company and Austin to amend the Agreement, the Company and Austin agree as follows: 1. AMENDMENT TO THE AGREEMENT. The Section 4.3 of the Agreement is hereby amended so that "Latest Closing Date" shall mean August 31, 2010 for all purposes related to the Agreement. 2. MISCELLANEOUS. Except as otherwise expressly provided herein, the Agreement is not amended, modified or affected by this First Amendment. Except as expressly set forth herein, all of the terms, conditions, covenants, representations, warranties and all other provisions of the Agreement are herein ratified and confirmed and shall remain in full force and effect. On and after the date on which this First Amendment becomes effective, the terms, "Agreement," "hereof," "herein," "hereunder" and terms of like import, when used herein or in the Agreement shall, except where the context otherwise requires, refer to the Agreement, as amended by this First Amendment. This First Amendment may be executed into one or more counterparts, and it shall not be necessary that the signatures of all parties hereto be contained on any one counterpart hereof; each counterpart shall be deemed an original, but all of which together shall constitute one and the same instrument. [SIGNATURES FOLLOW ON NEXT PAGE] IN WITNESS WHEREOF, this First Amendment to the Agreement is adopted effective as of the 14th day of July, 2010. "SELLERS" ___________________________________ ___________________________________ Clayton I. Gamber Kenneth W. Langston ____________________________________ Robin V. Gamber "PURCHASER" AVSTAR AVIATION GROUP, INC., a Colorado corporation By:_________________________________ Name:______________________________ Its:_________________________________ ________________________