AD 93-25-05

93-25-05 ALLISON: Amendment 39-8771. Docket 91-ANE-50. Applicability: Allison Model 250-C20S turbine engines, as modified by Soloy Conversion, Ltd., Supplemental Type Certificate (STC) SE2352NM, installed on but not limited to Cessna 206 and 207 airplanes. Compliance: Required as indicated, unless accomplished previously. To prevent bolt fretting and fatigue failure, main engine driveshaft detachment, and engine failure, accomplish the following: (a) Within 90 days after the effective date of this AD, inspect the main engine driveshaft and replace the driveshaft flex coupling bolts, bushings, and nuts in accordance with Soloy Corporation Service Bulletin No. 04- 780, dated December 11, 1991. Replace with a serviceable part those main engine driveshafts with elongated bolt holes. (b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Seattle Aircraft Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Seattle Aircraft Certification Office. (c) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. (d) The inspection, and replacement, if necessary, shall be done in accordance with the following service bulletin:

Document No. Pages Revision Date Soloy Corporation Service Bulletin No. 04-780 1-3 Original December 11, 1991

Total Pages: 3.

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Soloy Corporation, 450 Pat Kennedy Way, S.W., Olympia, WA 98501- 7298; telephone (206) 754-7000. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (e) This amendment becomes effective on February 22, 1994.