All 171 Boeing 737-9 Max aircraft will remain grounded until inspections are complete after an in-flight blowout on a passenger plane left a gaping hole in its side, the Federal Aviation Administration (FAA) has announced.
The Boeing jetliner made a dramatic emergency landing after a plug door was torn from its fuselage, shortly after it left Portland, Oregon, en route to Ontario, California on Friday.
Pilots turned back and safely landed the depressurised plane, which had been carrying 171 passengers and six crew members.
There were no major injuries reported, even as oxygen masks deployed and personal items were sucked out of the opening where the panel had been.
The missing panel was recovered on Sunday by a Portland school teacher who found it in his backyard.
The Boeing 737-9 Max aircraft will not fly until "enhanced inspections" of the jets are completed, including cabin doors, exit plugs, door components and fasteners, the FAA said on Monday.
The inspections of the 171 planes, mostly operated by US carriers Alaska and United Airlines, may take several days - forcing the cancellation of numerous flights.
The US aviation watchdog ordered the grounding for checks to be carried out of planes installed with the same kind of panel that fell from the jet on Friday, which weighs about 27kg and covers an optional exit door.
The organisation previously said it expected the inspections would take four to eight hours.
United Airlines cancelled 226 flights on Monday due to the grounding while Alaska Air said around 140 flights were cancelled.Boeing shares sank on Monday as the company reckons with the aftermath of the surprising panel emergency.
It was the latest setback for Boeing following a series of production delays that have hampered its recovery from a lengthy 737 MAX safety grounding in 2019.