AD 2021-13-10 Requires Repetitive Inspections For Any Existing Repair Of The Wing Lower Skin Fuel Tank...

The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 777 airplanes.

This AD was prompted by reports indicating that during investigation of a fuel leak, fatigue cracking was found on the forward inboard side of the fuel tank access door cutouts on the left and right lower wing skin. The cause of the cracking is attributed to corrosion damage. This AD requires repetitive inspections for any existing repair of the wing lower skin fuel tank and dry bay access door cutouts on the left and right lower wing skin, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective August 19, 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 777 airplanes. The NPRM published in the Federal Register on November 18, 2020 (85 FR 73430). The NPRM was prompted by reports indicating that during investigation of a fuel leak, fatigue cracking was found on the forward inboard side of the fuel tank access door cutouts on the left and right lower wing skin. The cause of the cracking is attributed to corrosion damage.

In the NPRM, the FAA proposed to require repetitive inspections for any existing repair of the wing lower skin fuel tank and dry bay access door cutouts on the left and right lower wing skin, and applicable on-condition actions. The FAA is issuing this AD to address fatigue cracking, which could result in the inability of a principal structural element to sustain limit load, and consequent reduced structural integrity of the airplane.

FMI: www.regulations.gov