Airlines are inspecting the controversial plane after a mid-air explosion forced an Alaskan plane to make an emergency landing.
United Airlines and Alaska Airlines said they found loose parts on several grounded Boeing 737 Max 9 planes, raising new concerns among industry experts about the manufacturing process of the passenger planes.
The Federal Aviation Administration (FAA), which regulates the industry in the United States, grounded 171 Max 9 planes worldwide after a cockpit panel blew up in the air on an Alaska-operated plane, forcing the pilots to make an emergency landing.
United said Monday that it “found bolts that needed additional tightening” in its initial inspections.
Alaska said early reports from its technicians indicated that some “loose hardware” was visible on some planes when it conducted checks on its fleet.
Airlines are focusing on an area known as a door plug, a cover panel used to fill an unnecessary emergency exit on planes that have been configured with fewer seats.
The panel that exploded on Friday’s flight to Alaska was a door plug, and the FAA ordered operators to ground all planes with the same configuration.
With 79 Max 9 aircraft, United has the largest fleet of aircraft in question. Alaska has 65 of those planes, while the rest are operated by Turkish Airlines, Panama’s Copa Airlines and Aeroméxico.
The mid-air incident has raised concerns about the production process and quality control of the Max 9. The model is used by relatively few airlines, but the 737 Max family of aircraft has been hit by controversy since the entire fleet world was grounded in March 2019 after two accidents in the space of six months killed 346 people.
Boeing said it would stay in close contact with Max 9 operators and help customers address any findings during the latest inspections.
“We are committed to ensuring that every Boeing aircraft meets design specifications and the highest safety and quality standards,” the US aircraft manufacturer said. “We regret the impact this has had on our customers and their passengers.”
On Monday, the FAA announced it approved a roadmap for carriers to complete inspections that include left and right door plugs, components and fasteners. He said the planes would remain grounded until operators completed “enhanced inspections.”
U.S. investigators continue to investigate Friday’s incident.
None of the plane’s 174 passengers or six crew members suffered serious injuries in the incident, even as oxygen masks were deployed and personal items were sucked out of the plane in the sudden depressurization.
The panel was recovered Sunday by a Portland teacher who found it in his backyard, said National Transportation Safety Board Chairwoman Jennifer Homendy.
The NTSB said recovering the fuselage would allow them to determine whether the plug was properly screwed into place or whether the bolts existed.
