Air accident investigators have called for “swift action” after a fuel leak was found to have caused an engine fire on a Cathay Pacific aircraft.
The carrier grounded aircraft to carry out inspections after the incident involving an Airbus A350 on take off from Hong Kong to Zurich on September 2.
A preliminary report by Hong Kong’s Air Accident Investigation Authority (AAIA) said: “This serious incident illustrates the potential for fuel leaks through the ruptured secondary fuel manifold hose, which could result in engine fires. Therefore, swift action is warranted.”
The report added: “If not promptly detected and addressed, this situation, along with further failures, could escalate into a more serious engine fire, potentially causing extensive damage to the aircraft,” the report said.
The aircraft was carrying 332 passengers and 16 crew members at the time of the incident.
The flight crew initially declared a mayday and discharged a fire extinguisher after shutting down the engine but later downgraded the status. They jettisoned fuel before returning to the airport after just over one hour.
The initial report found that a protective surround to a fuel hose had ruptured, leaving a “discernible hole” in the hose.
There were signs of a fire in parts of the engine including black soot and burn marks.
The AAIA recommended that the European Union Aviation Safety Agency (EASA) require Rolls-Royce to develop new inspection requirements for the relevant engines.
EASA responded in the days after the incident by requiring airlines using the same type of engine to carry out inspections of fuel pipes, and remove any that were “potentially compromised”.
The airline and engine manufacturer Rolls-Royce said they were continuing to support the Hong Kong investigation.
An AAIA spokesperson said that the preliminary report had been published to provide factual information established in the investigation’s early-evidence collection phase to both the aviation industry and general public in a timely manner, and should be regarded as “tentative”.
The spokesperson added: “The investigation team is conducting a detailed analysis of the data and information collected in order to determine the circumstances and causes of this occurrence with a view to preventing a recurrence in conjunction with identifying areas for further investigation or lines of inquiry to follow up.”
Cathay Pacific said that following the incident it had “proactively initiated a fleet-wide inspection of its Airbus A350 aircraft that cleared the aircraft for operation.”
The carrier added that it was in full compliance with EASA’s directive, and continued to “work closely with the airframe and engine manufacturers and regulator”.
Rolls-Royce told the BBC: “We are continuing to work closely with the regulators to support the ongoing investigation by the authorities into Cathay Pacific flight CX383.”
The company added that “the engine and aircraft system promptly detected and addressed the issue, as expected with such an incident”, with the crew being alerted and able to deploy the fire extinguisher.