Dennis Muilenburg

Boeing CEO Dennis Muilenburg leaves after testifying before a Senate Transportation Committee hearing on 'Aviation Safety and the Future of Boeing's 737 MAX' in Washington on Tuesday. AP Photo/Andrew Harnik

Boeing's top executive says the planemaker is taking steps to make sure employees' safety concerns are no longer ignored — something workers at the company's North Charleston plant have complained about in the wake of two 737 Max crashes in the past year.

CEO Dennis Muilenburg, responding to questions during a Senate hearing Tuesday about the crashes, said the aerospace giant is encouraging employees to speak up.

"We want to make sure they're heard and that we take action," he said.

Sen. Jon Tester, a Democrat from Montana, said there's been a history of Boeing management ignoring or never hearing about complaints, including a 2016 text exchange in which two Boeing pilots describe problems with a flight-control system implicated in the two crashes that killed all 346 people on board.

Muilenburg told senators he hadn't read the text mail exchange until recently, although his legal staff told him about it earlier this year.

"How did you just read this a couple of weeks ago?" Republican Sen. Ted Cruz of Texas asked, calling Muilenburg's apparent lack of concern over the document "truly stunning."

"What does that say about the culture at Boeing if they (Boeing's lawyers) didn't give it to you and you didn't read it ..." he said.

Another lawmaker — Republican Sen. Marsha Blackburn of Tennessee — called Muilenburg's lack of awareness "unsettling."

The problems extend beyond the 737 Max, Tester said, pointing to falsified certifications on cargo doors for hundreds of 777s and bolts and trash found on KC-46 tankers that Boeing had turned over to the Air Force.

"There was a South Carolina whistleblower that talked about debris being left in the planes," Tester said. "Those technicians were removed."

Tester's comment is an apparent reference to flight-line inspectors at Boeing's North Charleston plant who've complained about shoddy manufacturing at the 787 Dreamliner campus.

The company fired the five flight-line workers for allegedly missing a bird strike on a plane following a test flight. The National Labor Relations Board is reviewing whether the workers were instead fired because of their support for a labor union on the flight line.

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Sen. Maria Cantwell, a Democrat from Washington, said she is concerned about reports of Boeing eliminating hundreds of quality inspectors in North Charleston and the Seattle area, instead relying on mechanics to inspect much of their own work.

"I want to understand that a safety culture is going to exist," she said.

Boeing workers have told The Post and Courier that managers disregarded safety warnings in the past because dealing with them would slow production.

Muilenburg on Tuesday said Boeing wants to be sure concerns "are taken seriously and not brushed aside."

He said the company has restructured its safety review boards, reorganized its engineering department to focus more on safety and created a permanent safety committee on its board of directors. The company also has an anonymous hotline for employees to report safety concerns.

Reach David Wren at 843-937-5550 or on Twitter at @David_Wren_