Boeing CEO to tell lawmakers in 737 Max crash hearings: 'We know we made mistakes'

• Boeing CEO says the company has learned lessons from two fatal crashes of the 737 Max.
• Muilenburg submitted testimony ahead of his first congressional hearings after the two disasters.
• The planes have been grounded since March after the crashes killed 346 people.

Boeing CEO Dennis Muilenburg plans to tell lawmakers Tuesday that the manufacturer made mistakes with its 737 Max, its best-selling plane that is grounded worldwide after two fatal crashes that killed 346 people.

"We know we made mistakes and got some things wrong," Muilenburg said in written testimony ahead of two congressional hearings about the design and marketing of the planes. "We own that, and we are fixing them."

The hearings will be Muilenburg's first hearings on Capitol Hill since the crashes. The first will take place Tuesday, the one-year anniversary of Lion Air Flight 610 went down shortly after takeoff from Jakarta, before the Senate Commerce Committee. Another 737 Max crashed in Ethiopia in March. Muilenburg is also scheduled to testify Wednesday at a House Committee on Transportation and Infrastructure hearing.

Boeing has developed software fixes for a flight-control system on board the planes that pilots said they didn't know existed until after the first crash. Regulators haven't yet signed off on those changes, but Muilenburg has previously said the plane should be flying by the end of the year.

The crashes have forced Boeing to halt deliveries and slash production of the planes.

Boeing said it has flown more than 814 test flights with the new software.

Boeing President and Chief Executive Officer Dennis Muilenburg testifies before the Senate Committee on Commerce, Science, and Transportation on Aviation Safety and the Future of Boeings 737 MAX in the Hart Senate Office Building on Capitol Hill in Washington, DC on October 29, 2019.

Mandel Ngan | AFP | Getty Images

"I can assure you that we have learned from this and will continue learning," Muilenburg said in his statement. "We have changed from this and will continue changing."

Lawmakers are planning to press Muilenburg about the plane's development and whether the company's management was aware of or was the source of any pressure on employees to rush the plane to market.

Airlines have repeatedly delayed when they expect the planes to return to service. Currently no U.S. airline has the Max in its schedules until early next year, while Boeing has said regulators will likely sign off on the planes before the end of 2019.

This process has taken longer than we originally expected, but we're committed to getting it right, and return-to-service timing is completely dependent on answering each and every question from the FAA," Muilenburg said.