More than a year after the second deadly crash of a Boeing 737 Max airliner, the head of the Federal Aviation Administration faced bipartisan criticism Wednesday from lawmakers who accused his agency of continuing to withhold information about the development of the plane and its safety certification.

Sen. Roger Wicker (R-Miss.), chairman of the Senate Committee on Commerce, Science and Transportation, began the barrage against FAA Administrator Steve Dickson, spelling out how his investigators’ requests for information had gone unanswered.

“This record of delay and non-responsiveness clearly shows at best an unwillingness to cooperate in congressional oversight,” Wicker said. “It is hard not to conclude that your team at the FAA has deliberately attempted to keep us in the dark.”

Wicker soon offered an apology of sorts, saying the comments were “not really our style,” but Sen. Maria Cantwell (Wash.), the top Democrat on the committee, continued to press Dickson, saying she was not as genteel.

Despite investigations documenting the problems that caused two Max crashes within five months — one in Indonesia in October 2018 and the second in Ethiopia in March 2019 — killing a total of 346 people, Cantwell said the FAA appeared to have fallen back on “a rigid acceptance of the status quo than the needed changes that we want to see.”

The newly developed Max was set to be a vital part of airline fleets worldwide, but after the second crash, the FAA and aviation safety authorities around the world grounded the planes, dealing Boeing’s reputation a devastating blow. The Max still has not been cleared to fly again as the company and the FAA continue to work on safety improvements. The agency has not set a timeline for when that work will be completed, but it is expected to be done in coming months.

Dickson repeatedly pushed back against the senators’ criticism. He told Wicker that he understood the importance of Congress’s role and that it was wrong for Wicker to say his agency had been unresponsive.

“I am totally committed to the oversight process,” Dickson said. “I realize it’s an important matter for you. You have made that clear. You made it doubly clear this morning. I appreciate that.”

In both crashes, investigators have blamed a faulty automated system that the pilots were unable to counteract. The FAA had approved the revamped 737 as safe, but outside reviews have concluded that the automated system did not receive enough scrutiny.

Sen. Ted Cruz (R-Tex.), chairman of the aviation subcommittee, asked whether anyone at the FAA had been fired or disciplined as result of the problems. Dickson said they hadn’t.

“So unknown somebodies made unspecified mistakes for which there have been no repercussions,” Cruz said. “Is that right?”

Dickson said the agency has already begun rethinking its processes internally to avoid the problems occurring again. Cruz was not satisfied.

“You understand, sir, you do not work for the airlines and you do not work for Boeing,” Cruz said. “You work for the American people and this committee expects transparency. This committee expects that when we ask questions specifically about malfeasance that cost the lives of 346 people, that you will be forthcoming and answer those questions.”

Members of the House and Senate are both proposing to change the laws that govern how the FAA conducts its safety reviews, targeting in particular a system that lets employees of Boeing and other manufacturers conduct work on behalf of the government.

Legislation proposed by Cantwell and Wicker, announced on the eve of the hearing, would require the FAA to approve each individual company employee carrying out government safety work in an attempt to give them greater independence. But asked about that provision, Dickson said he didn’t think it would change much.

“The individual selection is not something that I believe would add to the safety of the process,” he said.

The bill would also guarantee that company safety engineers could communicate directly with FAA inspectors and would strengthen whistleblower protections. It also calls for major aviation manufacturers to adopt an organizational tool known as a safety management system that is already required of airlines, and would require the FAA to rethink its approaches to scrutinizing how human crew members and computerized systems work together.

Family members of the victims have traveled to Washington for past hearings, coming face-to-face with Boeing executives and FAA leaders and occasionally confronting them directly. But this time most were unable to come because of the coronavirus pandemic. The job of representing them fell to Michael Stumo, whose daughter Samya was killed in the second crash, an Ethiopian Airlines Boeing 737 Max.

He sat in a mostly empty hearing room and ran through the litany of failures and mistakes now known to have been made in the development of the Max and the government’s safety approval process, his loss adding emotional weight to his testimony.

“Samya’s 26th birthday will be in less than two weeks,” Stumo said.

When he was through with his opening statement, Wicker took a long pause. “There just aren’t any words we can say,” he said.

Unable to assemble in person, the families of the crash victims gathered afterward on Zoom, dialing in from more than a half-dozen countries. Many said they were glad to see the Senate taking up legislation, but they hoped for a law that might shorten Boeing’s leash further.

They also questioned Dickson’s leadership at the FAA, saying that like the senators they had seen too little transparency. Huguette Debets, who lost Jackson Musoni, the father of her children, in the second crash, said she wasn’t surprised that the families hadn’t gotten answers, but was shocked by the FAA’s apparent lack of respect for the Senate.

What the families are still waiting for, she said, is action.

“It’s nice to hear that everybody said sorry for your loss, sorry for loss,” Debets said. “We’ve gotten to hear that a million times, but our people aren’t coming back to us. What is going to be done?”