EASA AD US-2020-04-11: Fuselage - Upper Skin Lap Splice - Inspection

What to do

Operators of Boeing 747-400 series airplanes must perform the repetitive LFEC and HFEC inspections as specified in Boeing Alert Requirements Bulletin 747-53A2901 RB within the compliance times outlined in the document. Any detected cracks must be repaired before further flight using FAA-approved methods. The AD is effective April 13, 2020, and compliance must begin accordingly.

Summary

The Federal Register Volume 85, Number 46 Airworthiness Directive 2020-04-11 is a final rule issued by the FAA addressing certain Boeing 747-400 series airplanes. It mandates repetitive low frequency eddy current (LFEC) and high frequency eddy current (HFEC) inspections of the fuselage upper skin lap splice to detect fatigue cracks. The directive includes required on-condition repair actions to maintain structural integrity.

What changed

This new airworthiness directive introduces mandatory repetitive LFEC and HFEC inspections of a specific fuselage upper skin lap splice on Boeing 747-400 series airplanes. It addresses interference caused by a certain modification that hampers crack detection and requires applicable repairs if cracks are found. The AD also incorporates Boeing Alert Requirements Bulletin 747-53A2901 RB dated July 25, 2019, as the service information for compliance.

Why it matters

This AD is critical for aviation professionals because undetected fatigue cracks in the fuselage upper skin lap splice could lead to sudden decompression and loss of structural integrity, posing serious safety risks. Operators and maintenance teams must implement these inspections to ensure continued airworthiness and regulatory compliance. The directive helps prevent potential in-service failures and enhances overall fleet safety for affected Boeing 747-400 aircraft.

What to do

Summary

What changed

Why it matters

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