Overview of the Incident
On September 2, 2024, a serious issue was detected involving a Cathay Pacific Airbus A350-1000, where the aircraft’s second engine caught fire shortly after departure. This incident prompted an immediate response from both the airline and regulatory bodies. The flight, designated CX383, was en route to Zurich but had to return to Hong Kong after merely 75 minutes in the air due to the engine failure.
Detailed Investigation Findings
The preliminary investigation by Hong Kong’s Air Accident Investigation Authority (AAIA) discovered a significant rupture in the steel braided sheath of the fuel hose connected to the No.17 fuel spray nozzle. This defect was critical as it allowed fuel to leak, and when combined with oxygen and an ignition source, led to the fire. Moreover, inspection revealed additional damage including burn marks on the engine’s thrust reverser cowls and black soot on the rear engine cover.
Further examinations indicated that five other secondary fuel manifold hoses exhibited signs of wear such as frayed metal braids or internal collapse, which could potentially lead to similar hazardous outcomes. These findings underscored the urgency of addressing these issues promptly to prevent future risks.
Regulatory Response and Airworthiness Directive
Following the AAIA’s report, the European Aviation Safety Agency (EASA) issued an updated Airworthiness Directive (AD), extending the need for inspections beyond the A350-1000 to include some A350-900s. The directive was based on the discovery that a specific cleaning process used during engine refurbishment might degrade the integrity of the main fuel manifold hoses. This process, now discontinued, affected not only Trent XWB-84 engines commonly used in A350-900s but potentially also Trent XWB-75, Trent XWB-79, and Trent XWB-79B engines.
The EASA’s directive mandates inspections for aircraft with Trent XWB engines that have either accumulated 18,500 engine flying hours or more, undergone two or more shop visits, or achieved 2,300 engine flying cycles. The focus of these inspections is to identify any similar hose degradation and prevent incidents of engine fires.
Impact on Cathay Pacific Fleet and Proactive Measures
Reactively, Cathay Pacific launched a fleet-wide inspection covering all 30 of their A350-900s and 18 A350-1000s. The inspections aimed to identify and rectify any similar issues found during the preliminary investigation of the CX383 incident. This proactive measure was crucial in ensuring the safety and reliability of their operations, reflecting the airline’s commitment to passenger safety and regulatory compliance.
In collaboration with Rolls Royce and under the guidance of EASA, Cathay Pacific and other affected airlines began conducting precautionary inspections, particularly focusing on engines that had frequented specific maintenance facilities known for using the problematic cleaning process.
Conclusion and Ongoing Safety Enhancements
The AAIA continues its thorough investigation into the incident, with a comprehensive report expected to shed further light on the matter. Meanwhile, the proactive steps taken by Cathay Pacific, EASA, and engine manufacturers like Rolls Royce demonstrate a robust response aimed at enhancing flight safety and preventing future occurrences of similar issues.