EASA AD US-2021-13-10: Wings - Lower Wing Skin - Inspection

What to do

Operators of affected Boeing 777 airplanes must perform the required repetitive inspections of the lower wing skin fuel tank and dry bay access door cutouts starting by August 19, 2021. They must also carry out any necessary on-condition actions if damage or cracking is found. Maintenance and compliance teams should review Boeing Alert Requirements Bulletin 777-57A0118 RB dated June 23, 2020, for detailed procedures and ensure adherence to the AD requirements.

Summary

Federal Aviation Administration Airworthiness Directive 2021-13-10 is a final rule addressing certain Boeing Company Model 777 airplanes. It mandates repetitive inspections of the lower wing skin fuel tank and dry bay access door cutouts due to fatigue cracking caused by corrosion damage. The directive aims to ensure continued structural integrity and safety of affected aircraft.

What changed

This new airworthiness directive introduces mandatory repetitive inspections for existing repairs on the lower wing skin fuel tank and dry bay access door cutouts on both left and right sides of Boeing 777 airplanes. It also requires applicable on-condition actions such as detailed and high frequency eddy current inspections, corrosion blending, and repairs. The directive includes clarifications on compliance times and inspection procedures based on public comments.

Why it matters

This directive is critical for aviation professionals as it addresses a structural fatigue cracking issue that could compromise the wing's ability to sustain limit loads, potentially reducing airplane structural integrity. Operators and maintenance organizations must comply to prevent fuel leaks and ensure airworthiness. The inspections and repairs help maintain safety and avoid costly unplanned maintenance or operational disruptions.

What to do

Summary

What changed

Why it matters

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