Boeing mentioned on Thursday {that a} manufacturing subject would have an effect on its capability to ship a “important” variety of 737 Max jets, worsening plane shortages for airways all over the world.

The aerospace producer mentioned provider Spirit AeroSystems had used a “non-standard” course of when putting in two fittings within the fuselage of sure fashions of the narrow-body jet, creating the chance that it may not adjust to specs laid out by aviation regulators.

Shares of the corporate fell greater than 5 per cent in after-hours buying and selling. Spirit inventory fell greater than 11 per cent.

Boeing mentioned the planes can nonetheless function safely, however “the difficulty will most likely have an effect on a major variety of undelivered Max aeroplanes, each in manufacturing and in storage . . . We count on decrease near-term 737 Max deliveries”.

The delay will deepen complications for Boeing’s prospects, a lot of whom wish to increase their flying schedules, however they should safe extra planes to take action. Provide chain difficulties have left Boeing struggling to ship jets to massive prospects reminiscent of Southwest Airways. United Airways and Air India have additionally positioned massive orders just lately with the flagship US producer.

Michael O’Leary, the chief government of low-cost service Ryanair, spoke final month of probably shopping for extra planes from Boeing. The most recent delay, nevertheless, may immediate the resumption of earlier complaints about Boeing’s incapacity to ship.

A delay in deliveries additionally will hamstring Boeing’s money move, because it receives the majority of cost for a jet upon supply. The corporate reported $2.3bn in free money final yr, the primary time in three years that it generated more money than it spent. Buyers contemplate free money — working money minus capital expenditures — a main measure of Boeing’s monetary well being.

Boeing has been attempting to maneuver previous the turmoil that has gripped the corporate since two deadly crashes of the 737 Max prompted a worldwide grounding of the airplane, adopted by plummeting demand for air journey with the onset of the Covid-19 pandemic. It has struggled with manufacturing issues, from constructing Air Drive One to glitches on the 787 that halted deliveries for all however two months between October 2020 and August 2022.

Boeing mentioned that it had notified the US Federal Aviation Administration of the manufacturing downside and would examine the jets to search out and exchange the “non-standard” fittings.

Spirit mentioned it was working with Boeing to resolve the issue “and minimise impacts”.