U.S. lawmakers challenged Boeing Co. to expend the necessary time and effort to reset its safety culture and criticized the planemaker’s relationship with regulators as too cozy.

In her opening remarks at the Senate Commerce Committee on Wednesday, Senator Tammy Duckworth said Boeing needs to be judged by what it does, not by what it says it’s doing.

The Federal Aviation Administration, for its part, has been too soft at times policing the company. That, in turn, “sends an unmistakable message to both Boeing and its employees that bad behavior is acceptable,” Duckworth said.

“There’s still a long way to go to bring an effective safety culture back to Boeing,” the Democratic Senator from Illinois said.

The hearing is the first of two in Washington on Wednesday to explore Boeing’s safety record in the wake of a near-catastrophic accident in January, as well as two crashes of 737 Max aircraft a few years ago. The second panel will focus on claims by a Boeing engineer turned whistleblower, who alleges the company has cut corners in the production of its 787 airliner, placing profitability over safety. As a result, the aircraft might show premature signs of fatigue, he has alleged.

Boeing defended the safety and manufacturing of its marquee 787 Dreamliner, saying it had found no evidence of airframe fatigue after extensive testing of its carbon-fiber fuselage and heavy maintenance checks of nearly 700 of the jets already flying commercially.

“Under FAA oversight, we have painstakingly inspected and reworked airplanes and improved production quality to meet exacting standards that are measured in the one-hundreds of an inch,” the company said in a statement issued before the start of the hearings. “We are fully confident in the safety and durability of the 787 Dreamliner.”

Since a Boeing 737 Max 9 aircraft suffered the loss of the fuselage section, the FAA has tightened oversight of Boeing, forcing the company to slow down production and sending staff into their factories to review processes. The manufacturer has been given 90 days to come up with a comprehensive response and fix its production.

Senator Maria Cantwell, the Washington Democrat whose state is home to Boeing’s 737 Max factory and who chairs the Senate Commerce Committee holding the first Boeing hearing, said she expects the company to comply with that timeline.

Boeing executives aren’t present at either hearing, though the company has said it’s cooperating with the hearings.

Senator Richard Blumenthal, the Connecticut Democrat who chairs the second session, said today he expects Chief Executive Officer David Calhoun to appear “as part of our ongoing inquiry.”

“We expect Boeing’s full cooperation with our inquiry and look forward to this testimony,” he said.