EASA AD US-2023-17-14
Wings - Ring / Front Spar Lower Chords / Front Spar Webs - Inspection
Summary
Airworthiness Directive 2023-17-14 is a final rule issued by the Federal Aviation Administration (FAA) that supersedes AD 2022-18-11 and applies to all Boeing Company Model 777 airplanes. It addresses inspection and repair requirements for the left- and right-side ring chords, repair angles, front spar lower chords, and front spar webs related to the underwing longeron, with a focus on preventing cracking and ensuring proper application of fastener cap seals in fuel tank areas.
What Changed
This AD retains the inspection and repair requirements of AD 2022-18-11 but adds a maintenance records review for previously modified airplanes to verify proper cap seal application procedures. It corrects errors in the prior service information regarding fastener cap seal application, introduces new requirements to ensure correct sealant type and thickness, and clarifies applicability for certain Model 777 variants. It also excludes certain 777-200 airplanes without fuel tanks in the affected area from applicability.
Why It Matters
The directive is critical for aviation professionals because improper cap seal application can compromise lightning protection in fuel tanks, increasing the risk of fuel tank explosions during lightning strikes. Detecting and repairing structural cracks prevents fuel leaks and potential fire hazards. Compliance ensures continued airworthiness and safety of Boeing 777 fleets, protecting passengers and assets.
What To Do
Operators must comply with the inspection, modification, and on-condition repair requirements as specified, including reviewing maintenance records to confirm correct cap seal procedures were followed. For airplanes not yet modified or with uncertain records, rework of cap seals is required. The AD is effective September 15, 2023, and comments must be submitted by October 16, 2023.
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