Boeing has acknowledged for the first time that its anti-stall system on 737 Max jets played a role in two recent deadly crashes.
Boeing CEO made the admission as a preliminary report was released by investigators probing the cause of the Ethiopian Airlines crash last month.
"It’s apparent that in both flights the MCAS system activated in response to erroneous angle of attack information," Muilenburg said.
"It’s our responsibility to eliminate this risk. We own it and we know how to do it."
"We at Boeing are sorry for the lives lost and are relentlessly focused on safety to ensure tragedies like this never happen again," Muilenburg said in a video posted to Twitter.
Boeing recently completed a software fix for the problem although that was sent back for further tweaking, and could be several more weeks before it is ready to be approved by the FAA.
FAA inspectors were onboard a certification flight to test the new software, in mid-March, a Boeing official said.
"We’re taking a comprehensive, disciplined approach, and taking the time, to get the software update right," Muilenburg said.
The ‘cozy’ relationship between Boeing and regulator FAA has been called in question in recent weeks as all Boeing 737 Max jets were grounded.
Of particular concern to US lawmakers has been the ‘self-certification’ process where Boeing workers handle much of the work that goes into approving a new airplane model.
Former FAA chief of staff Michael Goldfarb reckons the software fix and subsequent approval could take months, with the FAA taking no chances.
"This will be treated differently from the way business is done. This will be micromanaged from (transportation) secretary Elaine Chao down," he told CNN.
