Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all 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 proposed 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 proposed AD would require 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 proposing this AD to address the unsafe condition on these products.