78-14-08 DETROIT DIESEL ALLISON: Amendment 39-3264 as amended by Amendment 39-3592. Applies to 250-C18/250-C18A/250-C18B/250-C18C/250-C20, and 250-C20B engines equipped with fuel pump P/Ns 6854292, 6856250, 6857548, 6876803, and 6877719, installed in aircraft certificated in all categories.
Compliance required as follows unless previously accomplished. To preclude possible engine flameout resulting from fuel pump drive spline failure: Remove and inspect the fuel pump drive splines in accordance with the procedures specified in Detroit Diesel Allison Commercial Service Letter 61 for the 250-C18 series engines and 1007 for the 250-C20 series engines, revision 3 or later FAA approved revisions and the compliance times specified in (a) and (b) below.
(a) For fuel pumps with 200 or more hours time in service on the effective date of this AD, compliance is required within 25 hours time in service and again each 200 hours time in service thereafter.
(b) For fuel pumps with less than 200 hours time in service on the effective date of this AD, compliance is required prior to reaching 225 hours time in service and again each 200 hours time in service thereafter.
If the pump drive splines exceed the wear criteria specified in the above Commercial Service Letters, the pump shall be removed from service before further flight except that the aircraft may be flown in accordance with FAR 21.197 to a base where the repair can be performed. Unacceptable spline wear may be corrected by replacing worn parts or by modifying the pump in accordance with Detroit Diesel Allison Commercial Engine Bulletins No. 161 for 250-C18 series engines and 1051 for 250-C20 series engines revision 1, or later FAA approved revisions.
All affected fuel pumps shall be modified in accordance with the procedures specified in the above referenced Commercial Engine Bulletins and the compliance times specified in (c) through (e) below. Upon completion of this modification the need and requirement for the above recurring inspection is eliminated. "Time in service" as specified in (c) and (d) below is the time since the last pump overhaul, or since new if the pump has never been overhauled.
(c) For fuel pumps with less than 1475 hours time in service on the effective date of this AD, compliance is required prior to reaching 1500 hours time in service.
(d) For fuel pumps with greater than 1475 hours time in service after the effective date of this AD, compliance is required within 25 hours time in service.
(e) All fuel pumps disassembled for heavy maintenance or overhaul shall be modified regardless of time in service, before being returned to service.
Operators who have not kept time in service records on individual pumps shall substitute engine hours time in service in lieu thereof.
The Detroit Diesel Allison commercial service information identified in this directive is incorporated herein and made part hereof pursuant to 5 U.S.C. 552(a)(1). The Detroit Diesel Allison Co. commercial service information incorporated herein may be obtained upon request to Detroit Diesel Allison, Division of General Motors Corporation, P.O. Box 894, Indianapolis, Indiana 46206. This document may also be examined at the FAA Great Lakes Region, 2300 East Devon Avenue, Des Plaines, Illinois 60018, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. 20591. A historical file on this AD, which includes the incorporated material in full, is maintained by the FAA at its headquarters in Washington, D.C. and the Great Lakes Region.
Amendment 39-3264 became effective July 20, 1978.
This Amendment 39-3592 becomes effective October 24, 1979.