According to crash investigators, bolts that helped secure a panel to the frame of a Boeing 737 Max 9 were missing before the panel flew off the Alaska Airlines plane last month.
The National Transportation Safety Board issued a preliminary report on the Jan. 5 incident on Tuesday.
The report included a photograph of Boeing working on the panel called the door stopper. In the photo, three of the four screws that prevent the panel from moving up are missing. The location of the fourth bolt is obscured.
Investigators said the lack of some damage around the panel indicates that all four bolts were missing before the plane took off from Portland, Oregon.
The pilots were forced to make a terrible emergency landing.
Without the bolts, there was nothing to stop the panel from sliding up and away from the “stop pads” holding it to the fuselage.
The preliminary report said the door plug, installed by supplier Spirit AeroSystems, arrived at Boeing’s factory near Seattle with five rivets damaged around the plug. A Boeing team replaced the damaged rivets, requiring the removal of four bolts to open the plug.
The NTSB did not declare a probable cause for the accident; that will come at the end of an investigation that could last a year or more.
“Whatever the final conclusion is reached, Boeing is responsible for what happened,” CEO David Calhoun said in a statement. “An event like this should not occur on a plane that leaves our factory. “We simply must do better for our customers and their passengers.”
Investigators said they were still trying to determine who authorized the Boeing crew to open and reinstall the door plug.
Safety experts have said the crash could have been catastrophic if the Alaskan plane had reached cruising altitude. Decompression in the cabin after the explosion would have been much stronger, and passengers and flight attendants could have been walking around instead of being buckled into their seats.
The incident added to questions about manufacturing quality at Boeing that began with the deadly crashes of two Max 8 planes in 2018 and 2019, which killed 346 people.
The Federal Aviation Administration is investigating whether Boeing and its suppliers followed proper safety procedures in manufacturing parts for the Max. The FAA has banned Boeing accelerate 737 production until the agency is satisfied with the quality problems.
FAA Administrator Michael Whitaker said Tuesday that his agency is about halfway through a six-week audit of the manufacturing processes of Boeing and its key Max supplier, Spirit AeroSystems. He said the agency faces two questions: what’s wrong with the Max 9 and “what’s happening with the production at boeing?”
Spirit AeroSystems, which Boeing spun off as an independent company nearly 20 years ago, said in a statement that it was reviewing the NTSB’s draft report and was working with Boeing and regulators “on continuous improvement of our processes and compliance with the highest safety standards. quality and reliability.”