STEVE INSKEEP, HOST:
The National Transportation Safety Board is asking why part of an Alaska Airlines jetliner blew out from the plane in midflight. Here's Kyra Buckley.
KYRA BUCKLEY, BYLINE: Officials have recovered a major piece of the Boeing 737 Max 9 that was torn from the body of the plane and fell into the backyard of a Portland-area science teacher. It's called a door plug because it plugs the spot where an emergency exit door could go. The door plug now makes its way to the NTSB labs in Washington, D.C. Investigators hope to determine why a hole was ripped in the side of the plane, forcing an emergency landing 20 minutes later at Portland International Airport. No significant physical injuries have been reported among the 171 passengers and six crew. NTSB Chair Jennifer Homendy said all four flight attendants aboard described a chaotic scene where it was challenging to communicate.
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JENNIFER HOMENDY: There's a lot of trauma that they are working through. It's going to be a long process. It was terrifying.
BUCKLEY: Homendy said, as the airplane cabin lost pressure, the cockpit door flew open to the surprise of the crew. Investigators learned the door is designed to open during rapid decompression, but the crew on the flight out of Portland didn't know that at the time. After the incident Friday, federal regulators grounded all Max 9 airplanes until they can be properly inspected. The two U.S. airlines that fly the planes, Alaska and United, have reported finding loose bolts on door plugs of other Max 9 planes in recent days. Homendy says investigators have not located the bolts from the torn-off door plug, but also don't know if that's what caused it to separate from the plane.
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HOMENDY: It's going to take time, and we're going to have to analyze the components and the door plug in our lab to be able to figure out how this happened and why this happened.
BUCKLEY: Homendy said they also plan to look at data on cabin pressure and other controls on the aircraft. Overall, the investigation could take anywhere from 12 to 18 months.
For NPR News in Portland, I'm Kyra Buckley.
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