The US National Transportation Safety Board (NTSB) has no specific details yet about why the mid-cabin door plug on an Alaska Airlines Boeing MAX 9 failed on Friday. The Board doesn’t want to speculate about the cause as the investigation has just got underway. Outside experts point to a manufacturing or oversight quality issue at either Boeing or tier-1 supplier Spirit AeroSystems, which produces the 737 MAX fuselage sections complete with door plugs.
During a press conference on Saturday evening, NTSB Chair Jennifer Homendy qualified the plug issue as an accident and not an incident, confirming how serious the blowout of the door plug and part of the cabin side wall could have been.
