AD NUMBER: 2013-20-51

PRODUCT: Agusta Model A109A, A109A II, A109C, A109E, A109K2, A109S, AW109SP, A119, and AW119 MKII helicopters.
SUBJECT: Airworthiness Directive 2013-20-51
ACTION: Final rule; request for comments.

SUMMARY: An emergency AD was sent previously to all known U.S. owners and operators of these helicopters. This AD requires, before further flight, inspecting certain Thomas coupling nuts on the tail rotor drive shaft line for a crack and replacing all the nuts if any nut is cracked.

Also this AD requires replacing all affected Thomas coupling nuts within 10 hours time-in-service (TIS) or 30 days, whichever occurs first. This AD was prompted by two incidents of cracking on the nuts that connect the flexible disc coupling (Thomas coupling) with the splined adapter on the tail rotor drive shaft. The FAA is issuing this AD to correct the unsafe condition on these helicopters.

DATES: This AD is effective October 25, 2013 to all persons except those persons to whom it was made immediately effective by Emergency AD 2013-20-51, issued on October 3, 2013, which contained the requirements of this amendment. Comments on this AD must be received by December 24, 2013.

FMI: AD