The UK Air Accidents Investigation Branch (AAIB) has released its report on an incident involving a Boeing 747-400F aircraft, registered G-UNET. The incident took place at London Heathrow Airport on 6 January 2024.
During a landing at Heathrow, an upper left wing panel detached from the aircraft. The component then came to rest in the grass area adjacent to the runway.
The flight crew remained unaware of the detachment, which was discovered during a post-flight inspection. The aircraft involved was a 33.5 year old converted freighter aircraft, belonging to the carrier OneAir.
Outline of the Heathrow Landing Incident
On January 6, 2024, Boeing 747-400F cargo aircraft, registered G-UNET, was conducting a landing on runway 27 Heathrow. It experienced an unexpected incident during the landing procedure.
An upper left wing panel detached from the aircraft at some point in the procedure. The detached panel then came to rest in the grass area adjacent to the runway. While the flight crew remained unaware of the detachment, it was discovered to be missing during a post-flight inspection.
The subsequent investigation by the UK Air Accidents Investigation Branch (AAIB) revealed a probable cause. It found that the likely cause of the panel detachment was fatigue cracking of the supporting rib.
This particular rib component has a history of susceptibility to cracking. This is a concern that Boeing, the aircraft manufacturer, acknowledged with the issuance of Service Letter (SL 747-SL-57-101-B). This service letter outlines recommended actions for operators to mitigate the risk of cracking in this area.
However, the AAIB report emphasizes that while these actions are only designed to reduce the likelihood of cracking. As such, they do not guarantee its prevention.
The continued occurrence of such incidents underscores the need for ongoing vigilance and adherence to manufacturer’s guidelines.
The Risk of FOD
While the detached panel at Heathrow itself posed a low risk of causing damage to the aircraft or injuring passengers, the primary safety concern identified by the AAIB was the potential for runway foreign object debris (FOD).
Any object on the runway, including the detached panel, presents a significant hazard to both landing and departing aircraft.
Although FOD detection systems are available to help mitigate this risk, their implementation is not universal across all major airports. The AAIB report highlights the importance of investing in and deploying these systems to enhance runway safety.
Aircraft Operator Actions & AAIB Findings
Following the Heathrow landing incident, the aircraft operator conducted a thorough inspection of the right wing of G-UNET to ensure compliance with Boeing’s Service Letter. This proactive measure aimed to prevent similar occurrences on the remaining wing.
The AAIB review also unearthed ten previous instances of similar panel detachments involving Boeing 747 aircraft.
These incidents occurred during various phases of flight, including landing, approach, and departure. This data further emphasizes the systemic nature of the issue and the need for a comprehensive approach to address the underlying causes of cracking in this critical component.
Summary
In conclusion, the AAIB report underscores the importance of adhering to manufacturer’s service bulletins, conducting thorough inspections, and investing in safety enhancements such as FOD detection systems.
By proactively addressing these issues, the aviation industry can strive to enhance flight safety and minimize the risk of similar incidents in the future.
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