3 hours Ago By Rytis Beresneviius
The European Union Aviation Safety Agency (EASA) has disclosed that it has issued a follow-up airworthiness directive (AD), which superseded the emergency AD (EAD) that the regulator had issued shortly after the incident involving a Cathay Pacific Airbus A350-1000. Cleaning process being the culprit In a statement on September 19, EASA said that after it had issued the EAD in response to the in-flight controlled shutdown of the number two engine on a Cathay Pacific Airbus A350-1000, in-service and in-shop inspections have revealed that a specific cleaning process available during engine refurbishment could lead to fuel manifold main fuel hose degradation. As a result, it issued its latest AD on the same day, whose effective date is October 3.
The directive applied to specific A350-900 and A350-1000 engines with certain engine serial numbers (ESN). The directive read that after being prompted by the discovery of the cleaning process’ potential role in the degradation of the fuel manifold main fuel hoses, maintenance organizations discontinued it following the instructions issued by Rolls-Royce. “Additionally, Rolls-Royce issued the NMSB [non-modification service bulletin – ed.
note], as defined in this AD, to provide repetitive inspections for populations of engines potentially affected by the suspect fuel manifold main fuel hose cleaning process.” EASA issued the aforementioned AD on September 5, shortly after Rolls-Royce had published its NMSB, mandating operators to inspect the Trent XWB-97 engine, which is exclusively used on the A350-1000. Cathay Pacific is excluded from the directive, having already performed its inspections.
Extending inspections to all Trent XWB engines While the EAD only applied to Trent XWB-97 engines, except certain engines with specific serial numbers (s/n), the European regulator extended the engine inspections to Trent XWB-75, XWB-79, and XWB-84s that were outlined by Rolls-Royce in the NMSB. The Trent XWB engine family consists of four engines – including one Trent XWB-79 derivative, the Trent XWB-79B – with different thrust ratings that directly correspond to their names. For example, the Trent XWB-75 has a net take-off thrust rating of 74,200 pounds of force, while the Trent XWB-84, used on the A350-900, has a net take-off thrust rating of 84,200 lbf.
Ch-aviation data showed that while no airlines currently use the Trent XWB-79 and XWB-79B engines, Singapore Airlines was the only carrier to utilize the Trent XWB-75 on 20 of its higher-density A350-900s. Four Singapore Airlines A350-900 that were equipped with a total of 303 seats (40 business and 263 economy class) also had the Trent XWB-84 engines. Nevertheless, EASA has now mandated inspections for several groups of engines.
Group A, B, and C engines, namely the Trent XWB-75, XWB-79, XWB-79B, and XWB-84s, have to be inspected within 30 days after October 3, before exceeding 8,000 flight hours (FH) since the applicable date listed in the NMSB, or before exceeding 2,000 FH since September 1. The engines were grouped in the Rolls-Royce NMSB, which was not available publicly. Group D and E engines, which were the Trent XWB-97s, had to be inspected before exceeding 2,000 FH after completing the inspections mandated by the EAD or before exceeding 2,000 FH since September 1, respectively.
All groups’ engines’ fuel manifold main fuel hoses had to be inspected without exceeding 2,000 FHs thereafter. In the case of damage or discrepancies, operators or maintenance organizations must refer to the Rolls-Royce NMSB for instructions to replace the affected parts, namely the fuel manifold main fuel hoses. An inspection and, in the case of a required part replacement, was enough to comply with EASA’s latest directive.
However, to terminate the requirement to inspect the engines and the affected part each time before an engine approaches 2,000 FHs, operators must replace the fuel manifold main fuel hoses with new parts according to instructions provided by either Airbus or Rolls-Royce. Lastly, airlines were mandated to report the results of their inspections to the engine maker within 30 days after checking their engines and the affected parts. Tim Clark stated that the engines of the Airbus A350-1000 cannot perform properly, which is why the airline has not ordered the A350-1000.
Urged by Hong Kong’s investigators When the Hong Kong Air Accident Investigation Authority (AAIA) published its preliminary report about the incident involving the Cathay Pacific A350-1000, registered as B-LXI, the investigators found a secondary fuel manifold hose that had ruptured, resulting in the engine fire. The engine fire was evident by the black soot that was spotted on the aft section of the core engine, with burn marks also being visible on the underside of the two thrust reverser cowls, the AAIA said. During the incident, less than a minute after the pilots had received a warning about the number two engine fire, the flight crew shut down the power plant and discharged a single fire extinguisher bottle within the engine, according to the investigators.
Concluding its preliminary report, the AAIA said that it had urged EASA to mandate A350 operators to inspect the hoses on their Trent XWB engines, which the European regulator did when it issued the aforementioned EAD on September 5. Hong Kong's investigators highlighted that it had recommended EASA to mandate Rolls-Royce to issue inspection instructions of the part..
