EASA AD US-2021-11-24
Fuel - Maintenance or Inspection Program - Revision
Summary
The Federal Aviation Administration's Final Rule titled 'Fuel - Maintenance or Inspection Program - Revision' is an airworthiness directive (AD 2021-11-24) applicable to certain Boeing 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This directive addresses updated airworthiness limitations related to fuel tank ignition prevention and the nitrogen generation system (NGS).
What Changed
This new AD requires operators to revise their existing maintenance or inspection programs to incorporate the April 2019 or November 2020 revisions of Boeing's airworthiness limitations document D626A001-9-04. It introduces updated requirements for the replacement and inspection of NGS oxygen sensors, including extended compliance times and options for off-wing inspections and repaired parts. The AD also clarifies applicability for certain maintenance tasks and extends compliance deadlines due to parts availability issues.
Why It Matters
This AD is critical for aviation professionals because it mitigates the risk of fuel tank explosions and engine flameouts caused by ignition sources or latent failures in the fuel system. Operators, maintenance, and compliance teams must ensure their programs meet these updated safety standards to maintain airworthiness and avoid operational disruptions. The extended compliance times and clarified applicability help reduce logistical burdens while maintaining safety.
What To Do
Affected operators must update their maintenance or inspection programs by July 20, 2021, to include the specified revisions of Boeing's airworthiness limitations document. They should comply with the revised requirements for NGS oxygen sensor replacement or inspection within the extended 36-month grace period. Operators may optionally incorporate the November 2020 revision to allow off-wing inspections and repaired parts, and they should monitor for any FAA-approved alternative methods of compliance.
Your fleet's weekly compliance brief
AI-summarized regulatory changes, compliance deadlines, and action items — filtered to your aircraft, every Monday.
AI-generated summary from official EASA source document. Always verify against the original.