Airworthiness Directive · Amendment 39-21462 · Tail rotor control system
Sikorsky Aircraft and Sikorsky Aircraft Corporation Helicopters
This AD applies to 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 helicopters, certificated in any category including restricted, with an arm assembly part number S6140-62614-009, installed.
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.
(1) Within 90 days after the effective date of this AD, review the mixer unit component log card or equivalent record to determine if the affected arm assembly is entered with the appropriate 15,000 hours TIS life limit.
(2) If the affected arm assembly is not included on the mixer unit component log card or equivalent record, within 90 days after the effective date of this AD, add the arm assembly entry to the mixer unit component log card or equivalent record and determine the remaining life of the arm assembly using the Accomplishment Instructions, Section 3.A.(3) of Sikorsky S-61 Helicopter Alert Service Bulletin (ASB) 61B40-11, Basic Issue, dated March 2, 2020 (the ASB).
(3) If, based on the review required by paragraphs (g)(1) and (2) of this AD, the arm assembly has accumulated 15,000 or more hours TIS, before further flight, remove the arm assembly from service. If the hours TIS for the affected arm assembly cannot be determined, before further flight, remove the affected arm assembly from service.
(4) For arm assemblies that have not accumulated 15,000 or more hours TIS, thereafter, continue to determine the remaining life of the arm assembly and remove the arm assembly from service before it accumulates 15,000 hours TIS.
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.
