EASA AD US-2023-12-18
Fuselage - Stringers and Stringer Splice Fittings - Inspection
Summary
Airworthiness Directive 2023-12-18 is a final rule issued by the Federal Aviation Administration (FAA) addressing certain Boeing 747-8 and 747-8F series airplanes. It mandates inspections of fuselage stringers and stringer splice fittings for cracking and the presence of radius fillers at fastener locations. The directive aims to ensure the structural integrity of these aircraft by identifying and correcting potential cracking issues in critical fuselage components.
What Changed
This new airworthiness directive introduces mandatory inspections of each free flange of the stringers at stringer splices for radius fillers and cracking. It establishes both flight cycle and calendar-based compliance times for initial and repeat inspections, reflecting updated findings of widespread cracking and concerns about repair reliability. The directive also requires applicable on-condition actions such as detailed inspections, removal or installation of radius fillers, and repairs as necessary.
Why It Matters
This directive is critical for maintaining the structural integrity of Boeing 747-8 and 747-8F airplanes by preventing failure of stringers and splice fittings that could compromise the aircraft's ability to sustain limit loads. Operators, maintenance, and compliance teams must address these inspections and repairs to avoid unsafe conditions that could lead to structural failure. The calendar-based compliance times also ensure inspections occur even for low-utilization aircraft, enhancing overall fleet safety.
What To Do
Operators of affected Boeing 747-8 and 747-8F airplanes must perform inspections for radius fillers and cracking at specified stringer splice locations according to Boeing Alert Requirements Bulletin 747-53A2907 RB dated March 3, 2022. Initial inspections must be completed before 12,000 total flight cycles, within 8 years of the original airworthiness certificate, or within 38 months after August 11, 2023, whichever is later. Repeat inspections and any necessary repairs must be conducted as specified in the directive.
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