What happened
During the en route climb phase of flight, a section of the inboard fixed wing panel separated from the aircraft structure. The separation occurred specifically over the wheel well area. This event resulted in significant structural damage to the airframe.
The investigation
Examination of the accident site and remaining aircraft components revealed that the loss of the panel was directly linked to fasteners attaching the wing panel to the aircraft. These fasteners had developed cracks. A review of maintenance records indicated that a Boeing Service Bulletin addressing cracked fasteners had not been complied with for this specific airframe. The aircraft involved had not been modified in accordance with the requirements of that service bulletin.
Findings
Investigation findings confirmed that the carrier operating the aircraft had previously experienced similar loss of the same panel type, indicating a recurring issue. The failure to implement the recommended service bulletin modifications allowed the cracked fasteners to persist and eventually fail under flight loads. The lack of compliance with the manufacturer's service directive was a critical factor in the structural separation.
Safety message
Strict adherence to manufacturer service bulletins is essential for maintaining airframe integrity. Operators must ensure that all relevant service directives are implemented promptly, particularly those addressing known fatigue or cracking issues in critical structural components.