AD 2020-18-12 Prompted By The FAA's Analysis Of The Model 777 Fuel System Reviews Conducted By The Manufacturer

The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 777-200, -200LR, and -300 series airplanes.

This AD was prompted by the FAA's analysis of the Model 777 fuel system reviews conducted by the manufacturer. This AD requires modifying the fuel quantity indicating system (FQIS) to prevent development of an ignition source inside the center fuel tank due to electrical fault conditions. This AD also provides alternative actions for cargo airplanes. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective October 26, 2020.

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 777 airplanes. The NPRM published in the Federal Register on May 4, 2016 (81 FR 26750). The NPRM was prompted by the FAA's analysis of the Model 777 fuel system reviews conducted by the manufacturer. The NPRM proposed to require modifying the FQIS to prevent development of an ignition source inside the center fuel tank due to electrical fault conditions. The NPRM also proposed to provide alternative actions for cargo airplanes. The FAA is issuing this AD to address ignition sources inside the center fuel tank, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

FMI: www.regulations.gov