Airworthiness Directive · Amendment 39-14700 · Sikorsky Aircraft Corporation Model S-92A Helicopters
Sikorsky Aircraft Corporation Model S-92A Helicopters
Model S-92A helicopter, with main gearbox (MGB) upper main housing assembly (housing assembly), part number 92351-15110-042, installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for the Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This action requires, before further flight, replacing a certain main gearbox (MGB) upper main housing assembly (housing assembly) that has 2700 or more hours time-in-service (TIS) with an airworthy part. This action also requires, before further flight, revising the Airworthiness Limitations section (ALS) of the maintenance manual by establishing a new retirement life for the MGB housing assembly of 2700 hours TIS. This amendment is prompted by testing of the MGB housing assembly that resulted in premature fatigue failure due to a manufacturing process creating an oxide skin defect in the housing. The actions specified in this AD are intended to prevent fatigue failure of the MGB housing, loss of MGB lube oil, loss of main and tail rotor drive, and subsequent loss of control of the helicopter.
Required as indicated, unless accomplished previously.
To prevent fatigue failure of the MGB housing, loss of MGB lube oil, loss of main and tail rotor drive, and subsequent loss of control of the helicopter, do the following:
(a) Before further flight, replace each MGB housing with 2700 or more hours time-in-service (TIS) with an airworthy MGB housing with less than 2700 hours TIS.
(b) This AD revises the Airworthiness Limitations section of the maintenance manual by establishing a new retirement life for the MGB housing assembly of 2700 hours TIS.
(c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Boston Aircraft Certification Office, FAA, ATTN: Wayne Gaulzetti, Aviation Safety Engineer, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7156, fax (781) 238-7170, for information about previously approved alternative methods of compliance.
(d) This amendment becomes effective on August 16, 2006.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
