AD 69-25-08

69-25-08 LYCOMING ENGINES: Amdt. 39-892 as amended by Amendment 39-938. Applies to Lycoming GO-435-C2A, GO-480, GSO-480 and IGSO-480 type engines using spline type reduction gear assemblies 72875 and 72879, GO-480 and GSO-480 type engines using flange type reduction gear assemblies 69346, 70412 and 71803 and IGO-540 and IGSO-540 type engines using reduction gear assemblies 72782, 74900, 75679, 76494 and 77731.

Compliance required unless already accomplished prior to the accumulation of six hundred (600) hours in service or 100 hours after the effective date of this AD whichever comes later for the GO-435, IGO-540 and IGSO-540 type engines and prior to the accumulation of seven hundred (700) hours in service or 100 hours after the effective date of this AD whichever comes later for GO-480, GSO-480 and IGSO-480 type engines. To prevent failure of the reduction gear assembly a one time inspection is to be accomplished as follows:

a. Check torque on reduction gearing pinioncage attaching nut.

1. If found to be in excess of 50 ft.-lbs. remove, inspect for damage and replace the oil retaining housing if necessary. During assembly comply with part (b) using a new lockplate and a pinion cage attaching nut torque of 400 ft.-lbs. When the assembly is disassembled replace thrust bearing oil slinger P/N 68319 with P/N 77454.

2. If found to be less than 50 ft.-lbs. disassemble the assembly and insure that all components meet approved specifications and replace the thrust bearing oil slinger P/N 68319 and P/N 77454 and the oil retaining housing. During assembly comply with part (b) using a new lockplate and a pinion cage attaching nut torque of 400 ft.-lbs.

b. If the pinion cage is secured with a spline nut it must be replaced with an approved hexagonal nut.

c. If the assembly has been rebuilt using thrust bearing oil slinger P/N 77454, stamp the suffix (-1) to the part number on the reduction gear housing.

Lycoming Service BulletinNo. 319A and Lycoming Service Instruction No. 1210A pertain to this subject.

Amendment 39-892 effective December 17, 1969.

This Amendment (39-938) is effective February 19, 1970.