SEATTLE/WASHINGTON (Reuters) – Boeing’s top commercial airplanes executive, Kevin McAllister, is leaving the company as the planemaker grapples with the fallout from two fatal crashes of its 737 MAX, the company said on Tuesday.

Boeing named company executive Stan Deal to succeed McAllister effective immediately as president and chief executive of Boeing Commercial Airplanes. Boeing has come under harsh criticism for failing to turn over instant messages from a former pilot to the Federal Aviation Administration (FAA) for months, prompting a demand for answers from the agency.

Deal joined Boeing in 1986 and was previously president and CEO of Boeing Global Services. Boeing is still working to win approval to unground the 737 MAX after the crashes that killed 346 people.

The management change was announced after Boeing’s board met in San Antonio.

Earlier on Tuesday, FAA Administrator Steve Dickson said Boeing was making progress toward winning approval to resume flights but would need “several weeks” before a key certification test flight can take place.

Next week, Boeing’s chief executive, Dennis Muilenburg – who was stripped of his title as chairman by the board this month – will testify before Congress for two days. “We’re committed to delivering on our commitments and regaining trust with our regulators, customers and other stakeholders,” Muilenburg said.

New board Chairman David Calhoun said the board backed the decisions. “Boeing will emerge stronger than ever from its current challenges and the changes we’re making throughout Boeing will benefit the flying public well into the future,” he said in a statement.