People familiar with the matter said the new problem has titanium parts that are weaker than they should have been on 787s built in the past three years.
The discovery joins a series of Dreamliner releases that have left Boeing with more than $25 billion worth of aircraft stranded in its inventory.
The problem lies in new evidence that the planemaker is still trying to overhaul its manufacturing operations, despite nearly two years of pressure from CEO David Calhoun to restore Boeing’s reputation for building high-quality planes.
In addition, the US Federal Aviation Administration (FAA) investigates Boeing’s quality controls.
The company admitted it had not solved the problem of waste left over from the production process, such as two empty bottles of tequila found in September on a new Air Force plane under construction in the country.
Regulators maintained closer control over production of the 737 Max after two failures. The accidents, which killed 346 people, were attributed in large part to Boeing’s faulty design of a new flight control system that sent planes into a deadly free fall.
A Boeing spokesman said the company was making progress in improving production and raising its own standards despite the operational disruptions.
“We have strengthened our focus on quality and are constantly encouraging all members of our team and our supply chain to raise any issues that need attention,” the spokesperson said. “When issues are raised, it is an indication that these efforts are paying off.”
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