AD 2021-11-24 Prompted By Significant Changes Made To The AwLs Related To Fuel Tank Ignition Prevention

The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes.

This AD was prompted by significant changes made to the airworthiness limitations (AWLs) related to fuel tank ignition prevention and the nitrogen generation system (NGS). This AD requires revising the existing maintenance or inspection program, as applicable, to incorporate the April 2019 or November 2020 revision of the airworthiness limitations document. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective July 20, 2021.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. The NPRM published in the Federal Register on May 6, 2020 (85 FR 26888). The NPRM was prompted by significant changes made to the AWLs related to fuel tank ignition prevention and the NGS. The NPRM proposed to require revising the existing maintenance or inspection program, as applicable, to incorporate the April 2019 revision of the airworthiness limitations document.

The FAA is issuing this AD to prevent the potential for ignition sources inside the fuel tanks and also to prevent increasing the flammability exposure of the center fuel tank caused by latent failures, alterations, repairs, or maintenance actions, which could result in a fuel tank explosion and consequent loss of an airplane. In addition, the FAA is issuing this AD to address the potential loss of engine fuel suction feed capability, which could result in dual engine flameouts, inability to restart engines, and consequent forced landing of the airplane.

FMI: www.regulations.gov