AD 2021-08-18 Prompted By The Discovery That Certain Part Numbers Listed In AD 2021-04-16 Are Incorrect

The FAA is superseding Airworthiness Directive (AD) 2021-04-16 which applied to certain Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters.

AD 2021-04-16 required a one-time inspection of the landing gear for components with non-conforming threads and removal of any non-conforming threaded hinge pin and main landing gear (MLG) and nose landing gear (NLG) actuator pins. AD 2021-04-16 also prohibited installing certain part-numbered hinge and actuator pins on any helicopter. This AD requires the same actions but corrects erroneous part numbers. This AD was prompted by the discovery that certain part numbers listed in AD 2021-04-16 are incorrect. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective April 29, 2021.

Supplementary Information: The FAA issued AD 2021-04-16, Amendment 39-21438 (86 FR 13631, March 10, 2021) (AD 2021-04-16), for Sikorsky Model S-92A helicopters with serial numbers (S/Ns) 920006 through 920334 inclusive. AD 2021-04-16 required a one-time inspection of the landing gear and the removal from service of certain serial-numbered threaded hinge pins part number (P/N) 92250-12281-101 and certain serial-numbered MLG and NLG actuator pins P/N 92250-12287-101 and 92250-12287-103.

AD 2021-04-16 was prompted by the manufacturer discovering nonconforming threads, resulting in a life limit reduction on multiple landing gear components including threaded hinge pins and MLG and NLG actuator pins. The FAA issued AD 2021-04-16 to prevent failure of components on the MLG and NLG. The unsafe condition, if not addressed, could result in damage to the helicopter and reduced ability to control the helicopter during landing.

FMI: www.regulations.gov