The National Transportation Safety Board (NTSB) has released a preliminary report on its investigation into the Jan. 5 Alaska Airlines flight 1282 door plug accident, saying that four bolts that would have prevented upward movement of the mid exit door (MED) plug were missing before the plug broke away from the plane.
On Jan. 5, the Boeing 737 MAX plane was flying from Portland, Oregon, to Ontario, California, at 16,000 feet of elevation when the MED plug broke away and the cabin immediately depressurized, causing minor injuries to seven passengers and one flight attendant.
According to the report, the MED plug had been temporarily removed from the plane’s main body, or fuselage, in order to replace five damaged rivets after the plane had arrived at Boeing’s manufacturing facility in Renton on Aug. 31, 2023.
The damaged rivets, which framed the MED plug, were replaced, but the four bolts were never put back into place after the MED plug was re-installed, the report says.
“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 aft upper guide track is covered with insulation and cannot be seen in the photo),” the report said, adding that the photo was shared in a text message between Boeing team members on Sept. 16.
According to the 19-page report, the ongoing investigation is looking to find what documents were used to authorize the opening and closing of the accident MED plug during the rivet rework.
The preliminary report was released Feb. 6 and on the same day, Boeing released an official statement, saying that the company was responsible.
“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. We simply must do better for our customers and their passengers,” said Boeing President and CEO Dave Calhoun. “We are implementing a comprehensive plan to strengthen quality and the confidence of our stakeholders. It will take significant, demonstrated action and transparency at every turn – and that is where we are squarely focused.”
Boeing says that the company is “taking immediate action to strengthen quality” by implementing a control plan that ensures all 737-9 MED plus are installed correctly. This includes:
• Instituting new inspections of the door plug assembly and similar structures at our supplier’s factory and on Boeing’s production line.
• Adding signage and protocol to fully document when the door plug is opened or removed in our factory, ensuring it is reinstalled and inspected before delivery.
The office of U.S. Sen. Maria Cantwell (D-WA) also released a statement on the NTSB report, saying that it “underscores” the importance of quality assurance from manufacturers and “how important quality control inspections from both manufacturers and the FAA are to the safety process.”