Plug doors are held in place by the higher pressure inside the aircraft. What happened on Alaska Airlines flight 1282 involved a door plug, which is held by bolts.
PORTLAND, Ore. — The depressurization incident on Alaska Airlines flight 1282 over Portland put an disconcerting spotlight on door plugs, a little-known component on certain aircraft including the Boeing 737 Max 9 from Friday’s flight. Door plugs seal up unused emergency exits and are only visible outside of the plane. From the inside, the door plug on flight 1282 looked like any other part of the cabin wall — until it suddenly blew out at 16,000 feet.
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