Airworthiness Directive · Amendment 39-10943 · Sikorsky Aircraft Corporation Model S- 61A, D, E, L, N, NM, R, and V Helicopters
Sikorsky Aircraft Corporation Model S- 61A, D, E, L, N, NM, R, and V Helicopters
Superseded. A later AD replaced this one: AD 2015-20-12. Comply with the one in force.
Model S-61A, D, E, L, N, NM, R, and V helicopters, with main rotor shaft (shaft), part number (P/N) S6135- 20640-001, S6135-20640-002, or S6137-23040-001, installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD), applicable to Sikorsky Aircraft Corporation Model S-61A, D, E, L, N, NM, R, and V helicopters, that requires a nondestructive inspection (NDI) for cracks in the main rotor shaft (shaft), and requires removal of any shaft with a crack and replacement with an airworthy shaft. This AD also requires appropriate marking of shafts and log book entries by the operator to determine the shaft retirement life, and establishes a new retirement life for the shaft. This amendment is prompted by four reports of cracks occurring in helicopters that were utilized in repetitive external lift (REL) operations. The actions specified by this AD are intended to detect a fatigue crack in the shaft that could result in shaft structural failure, loss of power to the main rotor, and subsequent loss of control of the helicopter.
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
