Boeing shares have tumbled more than 6 per cent after the US plane-maker disclosed a manufacturing issue affecting its 737 Max planes.

The aviation giant said a supplier had revealed that the installation of fittings on the rear of the planes did not follow the standard.

Boeing said the problem was not an “immediate safety of flight issue”. But it warned it could lead to delivery delays.

“We regret the impact that this issue will have on affected customers and are in contact with them concerning their delivery schedule,” the company said in a statement.

The latest problem comes as Boeing has been under intense scrutiny since two accidents in 2018 and 2019 involving its 737 Max planes killed 346 people.

Authorities said the accidents were triggered by design flaws in its flight control software.

Boeing ultimately agreed a $2.5 billion settlement with US authorities, who had accused the firm of concealing information from regulators about updates to the system. Thomas Hayes, chairman and managing member at Great Hill, said investors may be over-reacting to the current issue. Shares in Spirit Aerosystems, Boeing’s supplier, also plunged more than 20 per cent on Friday, following the disclosure.

Repeated errors

But, he added, “I can understand why it’s a shoot first and ask questions later because Boeing has impaired their trust with investors over the constant and repeated errors over the last few years.”

Boeing’s 737 Max was grounded for more than a year following the accidents. The company has also faced a series of supply issues as it tries to emerge from the cloud cast by that scandal and ramp up production.

In February, the firm was forced to halt deliveries of its widebody 787 Dreamliner due to a problem with its data analysis. US transportation regulators cleared Boeing to resume deliveries last month.

Boeing said a “significant number” of undelivered jets in production and in storage were affected by the new issue, which affects 737 Max family of airplanes.