AD 86-17-06

86-17-06 ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. (Allison, formerly Detroit Diesel Allison): Amendment 39-5370. Applies to Allison 501-D13, -D13A, -D13D, and -D13H engine reduction gear assemblies equipped with thrust sensitive switch assembly, P/N's 6792891, 6794122, 6794359, 6807776, 23005483, or 23005485.

Compliance is required within 60 days after the effective date of this AD, unless already accomplished.

To prevent the possibility of unwanted autofeather or the inability to autofeather when required, accomplish the following:

Replace thrust sensitive switch assemblies, P/N's 6792891, 6794122, 6794359, 6807776, 23005483, and 23005485 with P/N 6870559, a single carbon contact switch assembly, in accordance with the detailed instructions provided in Allison Commercial Engine Alert Bulletin CEB-A-73-84, Revision 2, dated October 1, 1984, or FAA approved equivalent.

Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.

Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Chicago Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018.

Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Chicago Aircraft Certification Office, may adjust the compliance time specified in this AD.

Allison Commercial Engine Alert Bulletin CEB-A-73-84, Revision 2, dated October 1, 1984, identified and described in this document, is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received this document from the manufacturer may obtain copies upon request to Allison Gas Turbine Division, General Motors Corp., P.O. Box 420, Indianapolis, Indiana 46206-0420. This document also may be examined at the Office of the Regional Counsel, FAA, ATTN: Rules Docket No. 82-ANE-50, 12 New England Executive Park, Burlington, Massachusetts 01803 and may be examined weekdays, except Federal holidays, between 8:00 a.m. and 4:30 p.m.

This amendment becomes effective on September 15, 1986.