Aerospace giant Boeing’s CEO is resigning, effective immediately Monday, as the company continues to grapple with decreased confidence in its 737 Max jet.

Dennis Muilenburg is stepping down, following an announcement last week that Boeing would halt production of the 737 Max. The jet was grounded worldwide in March after a second 737 Max crash, killing a combined total of 346 people.

“The Board of Directors decided that a change in leadership was necessary to restore confidence in the Company moving forward as it works to repair relationships with regulators, customers, and all other stakeholders,” the company said in a statement.

Boeing’s current board chairman, David Calhoun, will officially assume the post on January 13th.

An Ethiopia Airlines 737 Max crashed just after takeoff in March, killing all 157 people on board. Five months earlier, the same type of plane flown by the Indonesian airline Lion Air crashed shortly after takeoff, killing 189 people.

Investigators have focused on the MCAS system in the planes, a new automated flight system that was not included in previous versions of the 737. Investigators believe a faulty sensor in the MCAS system pushed the nose of each plane down and made it impossible for the pilots to regain control.