AD 2021-19-17: Sikorsky Aircraft Corporation Helicopters

This AD applies to Sikorsky Aircraft Corporation Model S-92A helicopters, certificated in any category, with the following installed: (1) A Martin-Baker side facing utility seat supplier part number (P/N) MBCS12410AA001 with a serial number (S/N) identified in Table 2 of Martin-Baker Special Information Leaflet (SIL) No. 831, dated July 10, 2019 (SIL 831), that is not marked with ``SIL831 incorporated;'' or (2) A Martin-Baker observer seat supplier P/N MBCS12200 or MBCS7301-2 with an S/N identified in Table 2 of Martin-Baker SIL No. 833, dated July 11, 2019 (SIL 833), that is not marked with ``SIL833 incorporated.'' Note 1 to paragraph (c): SIL 831 and SIL 833 are attached to Sikorsky S-92A Helicopter Alert Service Bulletin ASB 92-25-026, Basic Issue, dated March 5, 2020 (ASB 92-25-026). Note 2 to paragraph (c): Section 3., the Accomplishment Instructions, Tables 1 and 2 of ASB 92-25-026, specify cross references of Martin-Baker supplier P/Ns with Sikorsky P/Ns and kit P/Ns. Note 3 to paragraph (c): The marking ``SIL831 incorporated'' or ``SIL833 incorporated,'' as applicable, could be located adjacent to identification labels on the underside of the sitting platform assembly P/N…