737 Max 9's missing door plug found, may hold vital clues for blowout

US officials have recovered a panel that blew off an Alaska Airlines airliner triggering a partial grounding of Boeing's 737 MAX 9 and sending shares in the planemaker tumbling on Monday. A door plug tore off on Friday following takeoff from Portland, Oregon, en route to Ontario, California, depressurizing the plane and forcing pilots to turn back. The US Federal Aviation Administration on Saturday ordered the temporary grounding of 171 Boeing MAX 9 jets installed with the same panel, which weighs about 27 kg and covers an optional exit door.