Boeing will delay deliveries on approximately 50 737 Max aircraft to correct a newly discovered quality-control issue.
In a staff memo, Stan Deal, who heads Boeing's commercial airplanes division, said that a supplier had alerted the company that two holes in the bodies of some 737 Max planes were found to have not been drilled to precise specifications.
"While this potential condition is not an immediate flight-safety issue and all 737s can continue operating safely, we currently believe we will have to perform rework on about 50 undelivered airplanes," Deal said.
Boeing didn't reveal the supplier at issue, though various media outlets have said it is Spirit AeroSystems.
Spirit AeroSystems constructs approximately 70% of each 737 Max aircraft and delivers fuselages to Boeing.
In a statement, Spirit said, "A member of our team identified an issue that does not conform to engineering standards. Once notified, we began immediate actions to identify and implement appropriate repair solutions. We are in close communication with Boeing on this matter."
Boeing said it is finalizing rework instructions for affected airplanes. The company will continue to deliver 737 Max aircraft that aren't affected.
Boeing has come under intense scrutiny since the potentially catastrophic blowout of a 737 Max 9 exit door plug on a Jan. 5 Alaska Airlines flight. The door plug was subsequently recovered from the yard of a Portland-area resident and was missing four bolts that are designed to hold it in place.