(New York) American aircraft manufacturer Boeing tumbled on the New York Stock Exchange on Friday after news of further disruptions in deliveries of its flagship medium-haul 737 MAX aircraft, caused by quality problems on parts supplied by Spirit Aerosystems.

Boeing’s stock was down more than 6% at mid-session while its supplier’s stock fell about 20%.

The manufacturer said Thursday evening that Spirit Aerosystems used a “non-standard manufacturing process” in the installation of fittings in the fuselage of certain aircraft models 737-7, 737-8, 737-8-200 and P- 8.

This problem does not pose an immediate risk and the planes in service can continue to fly, assures Boeing.

But as some airlines lament that they don’t have enough planes to meet demand for airfares, deliveries of a “significant” number of 737 MAXs in production or still in inventory will drop in the near future. term, the time to carry out the inspections and, if necessary, to carry out modifications.

The company, which has set itself the goal of delivering between 400 and 450 MAX in 2023, did not specify exactly how many devices could be affected or how long it could take to resolve the situation.

This announcement represents a new setback for Boeing, which is trying to get back on its feet after several complicated years.

The aircraft manufacturer had to deal in quick succession with the two fatal accidents of the 737 MAX in 2018 and 2019, which led to the immobilization of the aircraft around the world for 20 months, the pandemic and its impact on traffic and supply chains, as well as manufacturing issues discovered on the 787 in the summer of 2020 that hampered long-haul deliveries for many months.

The group managed in 2022 to generate positive free cash flow over the whole year for the first time since 2018, a key indicator in its recovery.

But if deliveries of the MAX are seriously disrupted, the cash flow will decrease insofar as the companies pay the bulk of their order when they receive the planes.

“The story doesn’t fundamentally change,” remarks Morningstar analyst Nicolas Owens. “The planes are going to be delivered and Boeing is going to reduce its inventory. But it adds delays,” he adds in a note.