New details released on how door plug blew off Alaska Airlines plane

The left door plug on Alaska Airlines Flight 1282 slid off its hinges, disconnected from the fuselage and blew off the airplane, federal officials said Monday, providing a detailed account of the mechanics of what they believe happened Friday.

It’s unclear if the four bolts intended to prevent the door plug from disconnecting were in place, National Transportation Safety Board aerospace engineer Clint Crookshanks said at the late news briefing, accompanied by the board chair.

The accident happened minutes after the plane lifted off from Portland International Airport at 5:07 p.m. Friday. The sudden decompression tore a shirt off of a young passenger but did not cause any serious injuries. The captain circled back to the airport and landed.

Federal actions have taken several tacks since the accident. The Federal Aviation Administration ordered all airplanes of the same model to be grounded and inspected. United Airlines has said its inspections revealed loose bolts connected door plugs to airplane frames and Alaska Airlines said it has found loose hardware, too.

Whether similar issues caused or contributed to the door plug blowing off midair on Friday won’t be known for sure until the National Transportation Safety Board completes its analysis, which involves reviewing records, inspecting the airplane frame and door plug and interviewing crew members, among other necessary steps.

“We are in a fact-finding phase of the investigation,” NTSB Chair Jennifer Homendy said at an earlier press briefing. “The analysis of how this happened occurs later on.”

The door plug is installed by sliding it into hinges on the fuselage and is held in place by a combination of 12 fasteners — six on either side of the plug — that press against each other “like a high-five,” Homendy and Crookshanks explained Monday. Four bolts prevent the plug from sliding upward on the hinges.

”The exam to date has shown that the door in fact did translate upward, all 12 stops became disengaged, allowing it to blow out of the fuselage,” Crookshanks said.

The agency has not recovered the four bolts and is not sure whether they were in place to begin with, he said. Lab tests should answer that question, Homendy said.

The NTSB’s search for answers claimed a major victory with a Portland teacher’s discovery that the door plug had landed in the trees in his side yard. Bob Sauer, a science teacher at Catlin Gabel, contacted the NTSB on Sunday and inspectors retrieved the door plug from his yard early Monday.

“I’m sure he was a hit at school today,” Homendy said.

The agency is still looking for the door plug’s bottom hinge fitting — a green and circular piece of metal with a hole in it — and a spring, though the pieces aren’t critical to the investigation, Homendy said.

The press event Monday was the last on-site briefing of the investigation, the chair said.

— Fedor Zarkhin

Office: 503-294-7674; Cell: 971-373-2905; fzarkhin@oregonian.com

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