Airworthiness Directives; Sikorsky Aircraft and Sikorsky Aircraft Corporation Helicopters

FAA / Federal Register · 2021-06779

The FAA is adopting a new airworthiness directive (AD) for Sikorsky Aircraft Model S-61L, S-61N, S-61NM, and S-61R helicopters and Sikorsky Aircraft Corporation Model S-61A, S-61D, S-61E, and S-61V restricted category helicopters. This AD was prompted by the manufacturer determining that there may be arm assemblies in service that have accumulated 15,000 or more hours time-in-service (TIS), which exceeds the service life limit for this component. This AD requires reviewing the mixer unit component log card or equivalent record and, depending on the number of hours TIS, calculating the remaining life of the arm assembly or removing the arm assembly from service. The FAA is issuing this AD to address the unsafe condition on these products.