Investigators say an engine fire on a Cathay Pacific Airbus A350 earlier this month was caused by a fuel leak and may have caused extensive damage to the plane.
Hong Kong’s main airline was forced to turn back flights a few weeks ago due to an “engine part failure” and has since grounded planes.
The Trent XWB-97 engine is manufactured by British engineering giant Rolls-Royce.
A preliminary report from Hong Kong’s Air Accidents Investigation Agency (AAIA) said the accident was caused by one of several damaged fuel hoses breaking.
Both Rolls-Royce and Cathay Pacific Airways said they would continue to support the investigation.
The incident happened shortly after the plane took off from Hong Kong to Zurich in early September, after pilots received a fire warning in the cockpit, shut down the engines and used fire extinguishers.
The plane, carrying 348 passengers and crew, landed safely in Hong Kong.
But the incident raised concerns about the safety of the engines used across Cathay Pacific’s A350 fleet, especially after inspections revealed problems with 15 other planes.
A preliminary report found that a protective cover for a fuel hose had ruptured, leaving a “visible hole in the hose.” Parts of the engine showed signs of fire, including soot and scorch marks.
Further inspection revealed that five other fuel hoses on the same engine were also defective.
The report said that if not detected and addressed quickly, the situation “could have escalated into a more serious engine fire causing significant damage to the aircraft.”
To address this issue, the AAIA has recommended that the European Aviation Safety Agency (EASA) ask Rolls-Royce to develop new inspection requirements for the affected engines.
EASA responded a few days after the accident by requiring operators using the same type of engine to inspect fuel pipes and remove any that were “potentially damaged”.
The agency has since replaced those emergency measures with a more extensive inspection regime covering some makes of the Trent XWB engine. The agency said its inspections found that “certain cleaning processes available during engine refurbishment” could lead to deterioration of the fuel hoses.
Cathay Pacific said in a statement that following the incident it had “proactively commenced inspections of all Airbus A350 aircraft and cleared the aircraft for operation”, adding that the airline was fully complying with EASA instructions and “continues to work closely with aircraft and engine manufacturers and regulators”.
Cathay Pacific took delivery of its first Airbus A350 in 2016. The aircraft is fast becoming the mainstay of airlines’ long-haul fleets around the world, with its main selling points being its high efficiency and low operating costs.
The key to that efficiency is the engine: the Trent XWB, developed by Rolls-Royce specifically for the A350. The accident initially raised concerns that it could cause serious problems for the A350 fleet around the world, which would have been a major blow to the British manufacturer.
However, it soon became apparent that the problem was affecting the external fuel lines, rather than any moving parts of the engine itself, meaning the issue could be fixed relatively quickly without an expensive redesign.
The problem was initially thought to be limited to the XWB-97, a variant of a high-power engine that was fitted to a relatively limited number of long-range aircraft, but EASA is now calling for inspections of other versions as well.
Responding to the investigators’ report, Rolls-Royce said it “continues to work closely with regulators to support their ongoing investigations into Cathay Pacific flight CX383.”
The company also stressed that “as would be expected in an incident of this nature, the engine and aircraft systems quickly detected and responded to the problem,” and the crew were alerted and were able to deploy fire extinguishers.
Rolls-Royce announced plans this year to invest heavily in upgrading its engines, including the Trent XWB-97.
In 2023, Tim Clark, president of Gulf airline Emirates, expressed concerns about the durability of the engines and the maintenance fees charged by Rolls-Royce.
