Boeing 737 MAX 9 Blowout: Bolts Missing From Door On Alaska Jet, Says US Agency Report

A door panel that flew off a Boeing 737 MAX 9 jet mid-flight appeared to be missing four key bolts, according to a preliminary report that probed last month’s frightening mishap.

Tuesday’s National Transportation Safety Board (NTSB) report focused on how the panel – fitted into this MAX 9 model in place of an optional exit – could have detached from the plane. The plug is held down by four bolts and then secured by “stop fittings” at 12 different locations along the side of the plug and the door frame.

The US Federal Aviation Administration (FAA) grounded 171 of the Boeing 737 MAX 9 planes after the incident and Alaska Airlines for inspections. Those planes were cleared to return to service in late January and nearly all are flying again. “Whatever final conclusions are reached, Boeing is accountable for what happened. An event like this must not happen on an airplane that leaves our factory,” Boeing CEO Dave Calhoun said in a statement.

What Initial Findings Say

The plug was manufactured by Spirit AeroSystems, a former Boeing subsidiary. The part was produced at Spirit’s facilities in Malaysia and delivered to its Wichita, Kansas, facility in May 2023. It arrived at Boeing’s assembly plant in Renton, Washington on Aug. 31. The report shows the panel had to be removed at Boeing’s factory before being reinstalled. The initial findings released on Tuesday include photo evidence the bolts required to hold the plug in place appeared to be missing.

The report found the panel was first removed to repair rivet damage logged by Boeing workers on Sept. 1, a day after the panel arrived in Renton. Investigators are still trying to determine what documentation was used to authorize the opening and closing of the plug during the rivet repair. The report raises questions about who initially installed the bolts and why the door’s opening at Renton to correct the rivets was not properly documented, said U.S. aviation safety expert John Cox.

‘What’s Going On’

“When was the last time those bolts were installed? Did Spirit not install them and then when Boeing opened it the guys didn’t realize that they didn’t have the bolts? Or did Boeing not install them? That is something that I don’t think we have an answer for yet.” Senator Tammy Duckworth, who chairs an aviation subcommittee, questioned the lack of paperwork about the removal or replacement of bolts. “It is a series of problems,” Duckworth said in an interview. “What is going on between the maintenance and inspection teams… Holy cow – nobody noticed?”

Boeing said it had “implemented a control plan to ensure all 737-9 mid-exit door plugs are installed according to specifications.” The panel was found in a backyard in a suburb of Portland, Oregon, but the NTSB did not recover the bolts. A photo in the report shows three visible locations where bolts are missing, with the fourth location covered by insulation. “Photo documentation obtained from Boeing shows evidence of the left-hand MED plug closed with no retention hardware (bolts) in the three visible locations,” the report said. MED is short for “mid exit door.”

The incident has prompted regulators and lawmakers to ratchet up oversight of the jet manufacturer. The FAA in late January barred Boeing from expanding production of its 737 MAX planes due to the quality issues.  “I certainly agree that the current system is not working, because it’s not delivering safe aircraft,” FAA Administrator Mike Whitaker told lawmakers on Tuesday. “So we have to make changes to that.” The FAA is about halfway through a six-week audit of 737 MAX manufacturing. Spirit will invest in autonomous technology to limit any defects in its production of 737 fuselages, CEO Patrick Shanahan said on Tuesday following the company’s earnings.

(With agency inputs)