Boeing CEO Dennis Muilenburg acknowledged, for the first time, that bad data feeding into an automated flight system on the company's popular 737 jets played a role in two crashes that killed 346 people after Ethiopian aviation officials said their investigation found no pilot error in a March 10 crash in Addis Ababa.
"But with the release of the preliminary report of the Ethiopian Airlines flight 302 accident investigation it's apparent that in both flights the Maneuvering Characteristics Augmentation System, known as MCAS, activated in response to erroneous angle of attack information," Muilenberg said in a statement and video that was posted to the company's Twitter account Thursday.
The Ethiopian plane, which crashed just six minutes after take off from Addis Ababa, followed a similar flight pattern as a Lion Air flight that went down in Indonesia's Java Sea and killed all 189 passengers and crew in October. Pilots of both planes appear to have had trouble regaining control of the aircraft after an automated flight control system, called MCAS, pushed the nose of the jets down to keep them from stalling.
"The crew performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft," Ethiopian Transport Minister Dagmawit Moges told reporters at a news conference earlier Thursday.
Investigators found that pilots on the Ethiopian flight turned the anti-stall system off and back on again to try to regain control of the plane, casting doubt on Boeing and the Federal Aviation Administration's assertions that the crash may have been avoided had pilots simply followed established safety procedures.
Moges didn't specifically blame the MCAS software. However, she said it needed to be reviewed before the planes, which have been grounded since mid-March, are allowed to fly again.
"Since repetitive uncommanded aircraft nose-down conditions are noticed ... it is recommend that the aircraft control system shall be reviewed by the manufacturer," Dagmawit said. She also suggested that the aviation authority ensures the jet's flight control system is reviewed by Boeing before the jets are allowed to fly again.
Boeing and the Federal Aviation Administration had previously been trying to pin responsibility on the pilots.
Muilenberg said pilots say that false activation of the MCAS function, as happened in the Ethiopian crash, "can add to what is already a high workload environment."
"It's our responsibility to eliminate this risk. We own it and we know how to do it," said Muilenburg.
Muilenburg also said "we're deeply saddened by and are sorry for the pain these accidents have caused worldwide."
The company is taking a "comprehensive" and "disciplined" approach to get the software update right. Boeing anticipates its certification and implementation "in the weeks ahead." Muilenburg said Boeing remains confident in the fundamental safety of the 737 Max, which have been grounded since mid-March.
"When the MAX returns to the skies with the software changes to the MCAS function, it will be among the safest airplanes ever to fly," he said.
Muilenburg tweeted the video here:
Boeing stock closed up about by about 3 percent on Thursday.