Boeing has not provided crucial information sought by the National Transportation Safety Board as it investigates what caused a door panel to come off a 737 Max 9 plane during an Alaska Airlines flight in January, the safety board’s chairwoman told a Senate committee on Wednesday.
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.
Ms. Homendy’s comments set off a back-and-forth between Boeing and the safety board, with the two sides at odds over the plane maker’s level of cooperation with the agency.
Boeing has a team of 25 employees and a manager who handle doors at the Renton plant, Ms. Homendy told the Senate committee on Wednesday morning. 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.
In a statement after the hearing, Boeing said it had previously provided the safety board with “names of Boeing employees, including door specialists, who we believed would have relevant information.” The company added, “We have now provided the full list of individuals on the 737 door team, in response to a recent request.”
Boeing’s statement also suggested that the company might not have any records to hand over regarding the opening of the door plug. “If the door plug removal was undocumented, there would be no documentation to share,” the statement said.
A spokesman for the safety board, Eric Weiss, confirmed that on Wednesday afternoon, after the conclusion of the hearing, Boeing sent over the names of the 25 employees who handle doors in the Renton plant. But the plane maker did not specify who had worked on the door plug that blew off during the Alaska Airlines flight, Mr. Weiss said.
Lawmakers were quick to register their dismay over what Ms. Homendy had told them. Senator Maria Cantwell, Democrat of Washington and the chairwoman of the Commerce Committee, promptly sent a letter to Boeing’s chief executive, Dave Calhoun, calling for the company to provide the safety board with the information it requested within 48 hours.
“We cannot delay the important work of federal safety investigators,” she wrote.
Senator Ted Cruz of Texas, the top Republican on the committee, called the situation “utterly unacceptable.” He asked Ms. Homendy to report back to the panel in a week regarding the company’s cooperation.
Boeing is facing investigations by both the safety board and the Federal Aviation Administration over the episode on Jan. 5 with the Alaska Airlines jet, which had taken off from Portland, Ore. No one was seriously injured when the door plug blew off the plane at about 16,000 feet, but the mishap has prompted new scrutiny of the plane maker’s quality-control practices.
A preliminary report released by the safety board last month said that four bolts meant to secure the door plug in place were missing before the panel came off the plane. It outlined a series of events that occurred at Boeing’s factory in Renton that may have led to the plane being delivered without those bolts being in place.
At the factory, the door plug was opened so that damaged rivets on the plane’s fuselage, or body, could be repaired, and the four bolts needed to be removed to allow for the door plug to be opened, the report said. In a photograph of the door plug after it had been reinstalled, three of the bolts appeared to be missing, and the location of the fourth was not visible.
Ms. Homendy said at the hearing that the agency still did not know who had opened the door plug at the factory. “And it’s not for lack of trying,” she said.
Boeing has faced a wave of criticism since the episode on the Alaska Airlines flight. The F.A.A. barred the plane maker 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.
“This is about fixing the system, and it’s hard to fix the system if we don’t know what happened,” Ms. Cantwell told reporters after the hearing. She said that her committee was working on arranging hearings with Mr. Calhoun and with the F.A.A. administrator, Mike Whitaker.