N.T.S.B. Says Boeing Has Not Provided Key Information in 737 Max Inquiry

The chairwoman of the National Transportation Safety Board told a Senate committee on Wednesday that Boeing was dragging its feet in providing some information to the agency as it investigates what caused a door panel to come off an Alaska Airlines plane during a flight in January.

The official, Jennifer Homendy, told the Senate Commerce Committee that her agency had requested any documentation that exists regarding the opening and closing of the panel, known as a door plug, at Boeing’s factory in Renton, Wash. Ms. Homendy said the safety board had also requested the names of certain workers at the factory.

Boeing has a team of 25 employees and a manager who handle doors at the Renton plant, Ms. Homendy told the Senate committee. The manager has been on medical leave, and the agency had been unable to interview that person, Ms. Homendy said. She added that Boeing had not provided the safety board with the names of the other 25 employees.

“It’s absurd that two months later, we don’t have that,” she said.

Boeing did not immediately respond to a request for comment.

The plane maker is under investigation by the safety board and the Federal Aviation Administration over the episode on Jan. 5 with the Alaska Airlines jet, a Boeing 737 Max 9 that had taken off from Portland, Ore. No one was seriously injured when the door plug came off the plane at about 16,000 feet, but the mishap has prompted new scrutiny of Boeing’s quality-control practices.

A preliminary report released by the safety board last month said that four bolts meant to keep the door plug in place had been removed at Boeing’s factory in Renton and appeared not to have been reinstalled before the plane was delivered.

Boeing has faced a wave of criticism since the episode. The F.A.A. barred the company from expanding production of the 737 Max series until it addressed quality-control issues, and last week, the regulator gave the company 90 days to develop a plan to make improvements.