EASA AD US-2021-19-17
Equipment / Furnishings - Utility Seats and Observer Seats - Modification
Summary
Federal Aviation Administration Airworthiness Directive 2021-19-17 is a final rule addressing certain Sikorsky Aircraft Corporation Model S-92A helicopters equipped with specific Martin-Baker side facing utility and observer seats. The directive responds to an incident where a side facing utility seat detached from its wall attachment points, posing a safety risk. It mandates modification of these seats to replace the main back tube assembly to ensure compliance with airworthiness standards.
What Changed
This new airworthiness directive requires operators to modify affected side facing utility and observer seats by replacing the main back tube assembly according to Sikorsky Alert Service Bulletin 92-25-026 and Martin-Baker Special Information Leaflets 831 and 833. It also prohibits installation of these seats unless the modification has been completed. The directive clarifies responsibilities related to seat installation compliance and addresses comments received during the rulemaking process.
Why It Matters
This directive is critical for aviation professionals to prevent seat detachment during dynamic conditions, which could lead to injury or fatality. Operators and maintenance organizations must ensure that affected seats meet certification requirements under 14 CFR 29.562 to maintain aircraft airworthiness. Compliance ensures continued safe operation of Sikorsky Model S-92A helicopters and adherence to FAA regulations.
What To Do
Operators of Sikorsky Model S-92A helicopters must replace the main back tube assembly on affected Martin-Baker side facing utility seats (P/N MBCS12410AA001) and observer seats (P/Ns MBCS12200 and MBCS7301-2) following the procedures in Sikorsky ASB 92-25-026 and Martin-Baker SIL 831 or SIL 833. The modification must be completed by November 22, 2021, the effective date of the AD. Installation of affected seats without this modification is prohibited.
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