Investigators Will Probe If Alaska Airlines 737 Max’s Door Panel Was Securely Bolted

Topline Federal investigators are trying to establish if the door panel that blew off an Alaska Airlines jet last week was properly bolted in place, National Transportation Safety Board officials said late on Monday, hours after both United and Alaska Airlines found loose bolts on door panels of several of their grounded Boeing 737 Max 9 planes.

In this National Transportation Safety Board (NTSB) handout, an opening is seen in the fuselage of ... [+] Alaska Airlines Flight 1282 Boeing 737 9 MAX in Portland, Oregon. Key Facts In a press conference in Portland on Monday night, NTSB chair Jennifer Homendy said the agency is probing if the bolts meant to secure the panel were missing when the aircraft took off or “came out during the violent, explosive decompression event.” The panel or door plug that blew off the Alaska Airlines plane is used in place of an optional emergency exit door in planes with less dense seating arrangements.

These door plugs are secured in place by four bolts that prevent the panel from sliding up and detaching from the plane and the NTSB has not yet recovered the bolts, agency official Clint Crookshanks told reporters. The panel is also held in place by 12 stop fittings, but the door plug on the Alaskan Airlines flight slid up “disengaged from the stops, which then fractured the fittings,” Crookshanks added.

Homendy said the agency will be able to determine if the bolts were in place before the blowout, after examining the recovered door plug at their lab in Washington D.C. News Peg Earlier on Monday, United Airlines—which has grounded its 79 MAX 9s—said it had found loose bolts on door plugs of several grounded aircraft during inspections.

United referred to them as “installation issues in the door plug” and in some cases, the bolts needed “additional tightening.” Alaskan Airlines—which has grounded 65 Max 9s—also issued a statement that inspections by its technicians “indicate some loose hardware was visible on some aircraft.” The airline said the planes would be “thoroughly inspected” based on the Federal Aviation Administration’s guidelines and all findings would be documented and shared with the FAA.

“No aircraft will be returned to service until all of these steps are complete,” the statement added. Further Reading Boeing Shares Nosedive 8% After Door Incident (Forbes) Jet Door Blown Off Alaska Airlines Plane Is Found In Oregon Schoolteacher’s Backyard (Forbes).