Boeing has revealed that deliveries of its bestselling 737 Max plane will be delayed, in the latest blow to the US manufacturer in its long recovery from a crisis started by the troubled model. The company said a “significant” number of 737 Max deliveries would be delayed because a supplier, Spirit AeroSystems, had made a component using a “non-standard” manufacturing process. The problem is not an “immediate safety of flight issue” so planes already in service can continue to operate, Boeing said. The setback will probably delay revenues while the company reinstalls the affected fittings, which are used to hold the vertical tail stabiliser in place. Boeing could also face costs to replace the parts on planes going back as far as 2019. It is the latest problem for Boeing, just as it was recovering from several years of crises that began when critical flaws in its 737 Max led to two deadly crashes. In 2018 and 2019, 346 people died when hardware malfunctions and badly designed software caused the planes to override pilots and plunge from the sky. The 737 Max crisis was followed by the coronavirus pandemic, which caused the grounding of airline fleets worldwide, and a steep decline in new aircraft orders. It prompted the European planemaker Airbus and Boeing to cut tens of thousands of jobs. The latest announcement came only two days after data showed that Boeing delivered more planes than Airbus in the first three months of 2023 – 130 versus 127 – the first time the US manufacturer has beaten its bitter rival during a quarter since 2018. Airbus delivered 663 planes last year compared with Boeing’s 480. Both manufacturers had been aiming to increase their rate of production, with Boeing also hoping to put behind it problems with its larger 787 plane and pull back in the battle with Airbus. Ryanair, Europe’s largest carrier, had been expecting to take delivery of 24 737 Max aircraft by June as part of an aggressive post-Covid expansion. The airline has said it expects passenger numbers to reach 185 million in the year to March 2024, up from 168 million in the year to March 2023. In a statement to the Telegraph, it said Friday’s announcement does not affect its current fleet, but that it was “assessing with Boeing how this will impact” the deliveries it is expecting this summer. Investment bank analysts said it was unclear how long it would take Boeing to correct the problems, or how much it would cost. The company’s New York-listed share price dropped by 5% in after-hours trading, while those of Spirit dropped by 12%. “There will likely be required rework for a portion of the in-service fleet, with timing unknown,” wrote Sheila Kahyaoglu, an analyst at the investment bank Jefferies, in a note to clients. “There is an investigative process along with determining the root cause and remedy, that could have an unknown timeline to complete.”