Cathay Pacific was forced to ground all A350-1000 jets to carry out inspections following the discovery of a potential issue with the fuel nozzle on the Rolls-Royce engines. The airline has 48 operational A350 aircraft — and identified 15 affected aircraft (A350-1000) that need replacement components. “The remaining aircraft will continue to be out of service until they have been repaired and cleared for operation. We expect that all affected aircraft will resume operations by Saturday”, Cathay Pacific said.The grounding was initiated after an incident that occurred on one of its 18 A350-1000 aircraft.A problem unfolded several minutes after take-off on flight CX383 from Hong Kong to Zurich on Monday, according to flight tracking service FlightRadar24.The five-year-old A350-1000 performed two holding circles and dumped fuel over the sea before returning to Hong Kong where it landed safely around 75 minutes after its departure. Cathay Pacific said it identified an engine component failure after the aircraft returned to Hong Kong.Cathay Pacific has not specified which engine component failed, but the carrier said it was the “first of its type to suffer such failure on any A350 aircraft worldwide”.The part involved is understood to be a fuel nozzle inside a XWB-97 engine (the Rolls-Royce engine used on the A350-1000). Engineers were asked to make specific checks to the flexible hoses supplying fuel to the engine for abnormalities, deformation, kinks, bulges or degradation.It has since identified 15 aircraft with engine components that require replacement and three have already gone through repairs. Cathay Pacific has cancelled at least 34 round-trip flights between Hong Kong and Sydney, Osaka, Tokyo, Taipei, Bangkok and Singapore until the end of Wednesday.Rolls-Royce on Tuesday noted the replacement could take place while the engine remained on-wing, which will significantly reduce the required maintenance time. It also said it was committed to working closely with Cathay Pacific, Airbus and authorities investigating of the incident. The Civil Aviation Administration of China had initiated its own investigation to determine whether any A350 aircraft operated by mainland airlines needed to be checked.There are 88 A350-1000 jets in operation worldwide - the most with Qatar Airways, here in Doha. The top six operators are Qatar Airways with 24 of the variant, British Airways with 18, Cathay Pacific with 18, Virgin Atlantic with 12 and Etihad Airways and Japan Airlines with five each. Tokyo-based JAL, which has five A350-1000s that are all less than a year old, said it has asked Rolls-Royce for more information and had not suspended A350 flights in the meantime.Thai Airways chief executive officer Chai Eamsiri spoke to local media about the matter, explaining the Thai national carrier had not ordered suspension of its 23 Airbus A350 aircraft.He confirmed that the airline’s maintenance department inspected all aircraft regularly in line with safety standards. “Currently, there are no abnormalities in the aircraft’s engine,” he said. Chai affirmed that the maintenance department would submit a report if any abnormalities were found in the aircraft. He said the reason behind the problems with Cathay Pacific’s aircraft was still unclear, but he vowed to monitor this issue.“Thai Airways would like to confirm that the Airbus A350 fleet is still operating flights as normal, and the airline would continue regular inspections of the aircraft condition regularly in line with safety standards,” he said.The A350-1000 and the A350 freighter use Trent XWB-97 engines, Rolls-Royce’s largest civil jet engine. A350-900 uses its Trent XWB-84 engines, which is so far unaffected.Prior to Cathay’s discovery, the Rolls-Royce engine on the A350, particularly the larger -1000 variant, had already attracted criticism from some airlines. Emirates, for instance, scaled back its initial large order, with President Tim Clark labelling the engine’s power plant as “defective” due to its demanding maintenance needs in harsh climates like the Middle East.Rolls-Royce previously encountered significant challenges with its Trent 1000 engine, which powers the Boeing 787 Dreamliner. Despite Rolls-Royce’s claims of substantial improvements, these issues severely impacted its market standing, allowing GE to secure a dominant position with that aircraft. British Airways recently opted for the American manufacturer’s engines for its 787 fleet, highlighting how economic factors can outweigh any loyalty airlines might feel toward their suppliers.Smaller, single-aisle Airbus A320neo jets, equipped with Pratt & Whitney engines, have experienced technical issues that have led to the temporary grounding of some aircraft within this critical fleet.In recent years, supply chain constraints in the production of new jets have worsened, as aircraft already in operation require additional parts due to in-service problems. Airlines generally maintain limited spare parts inventories to minimise costs, further exacerbating the situation.n The author is an aviation analyst.X handle: @AlexInAir