United, Alaska find loose parts on 737 MAX planes, raising pressure on Boeing

National Transportation Safety Board (NTSB) Investigator-in-Charge John Lovell examines the fuselage plug area of Alaska Airlines Flight 1282 Boeing 737-9 MAX, which was forced to make an emergency landing with a gap in the fuselage, in Portland, Oregon, U.S. January 7, 2024. NTSB/Handout via REUTERS.

WASHINGTON/CHICAGO (Reuters) -Boeing's latest 737 MAX crisis deepened after United Airlines and Alaska Airlines said they had found loose parts on multiple grounded MAX 9 aircraft, raising new concerns among industry experts about how its best-selling jet family is manufactured.

U.S. regulators grounded 171 MAX 9 planes after a panel blew off an Alaska Airlines-operated flight not long after taking off from a Portland, Oregon, airport on Friday, forcing pilots to scramble to land the plane safely.