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 US aviation safety expert John Cox.
“When was the last time those bolts were installed? Did Spirit not install them and then when Boeing opened it the guys didn’t realise 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.”
Boeing said it has “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. The agency also did extensive tests and analysis to determine if they had been present before the crash or had come undone during the incident, it said.
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 says. MED is short for “mid exit door.”
Boeing under pressure
The incident has prompted regulators and politicians 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. That means it can continue producing MAX jets at its current rate, but it cannot increase that rate.
“I certainly agree that the current system is not working, because it’s not delivering safe aircraft,” FAA Administrator Mike Whitaker told politicians. “So we have to make changes to that.”
Boeing’s Calhoun bowed to lawmaker pressure to drop a request for a temporary exemption from design rules for a different MAX model, and more hearings in Washington will be held, Senate Commerce Committee Chair Maria Cantwell said.
“The NTSB’s preliminary report on the Alaska Airlines Flight 1282 accident underscores how important quality assurance is from manufacturers and how important quality control inspections from both manufacturers and the FAA are to the safety process,” she said.
The FAA is conducting an audit of 737 MAX manufacturing, which is looking at all elements of production at Boeing and fuselage production at its supplier Spirit.
Spirit AeroSystems will invest in autonomous technology to limit any defects in its production of Boeing 737 fuselages, CEO Patrick Shanahan said on Tuesday following the company’s earnings.
Boeing shares closed up 1 per cent on Tuesday. The stock has lost more than 20 per cent of its value since the beginning of the year. Spirit shares ended up 5 per cent after reporting results.
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