April 29 (UPI) -- Boeing CEO Dennis Muilenburg said Monday that pilots did not "completely" follow the company's procedures in two crashes involving its 737 Max airliner.
Speaking to media after a shareholder meeting in Chicago, Muilenburg said Boeing was unable to find any "technical slip or gap" in its anti-stall software -- known as the Maneuvering Characteristics Augmentation System -- that was linked to both crashes.
"When we design these systems, understand that these airplanes are flown in the hands of pilots," he said.
Muilenburg also reiterated the company's stance that it "owns" the responsibility to update the software, but doesn't entirely "own" the Ethiopian Airlines and Lion Air crashes that collectively resulted in 346 deaths.
Reports detailing the events of both crashes mentioned that inaccurate sensor readings related to MCAS occurred prior to the crashes. Muilenburg said these issues were "one link in a longer chain of events," but didn't indicate a design flaw.
"There are multiple contributing factors. There are factors that we can control in the design and in this case that common link related to the MCAS system and its activation," Muilenburg said. "We're going to break that link and this will prevent accidents like this from happening again."
Muilenburg also disputed reports that pilots had not been properly made aware of MCAS, saying it is "not a separate system" but rather something that is included in training a pilot to fly the plane.
"We want the airplane to behave in the air similar to the previous generation of 737s -- that's a preferred pilot feel for the airplane, how it feels as they're flying it," he said. "MCAS is designed to provide those kind of handling qualities at high angle of attack. So it's a purposeful design."
American Airlines pilot and union spokesman Capt. Jason Goldberg told NPR pilots do train to overcome pitch adjustment system issues, but MCAS malfunctions create other problems.
"You would have the stick shaker, which [activates] a rather violent aggressive shaking of the control column," Goldberg said. "You would have the appearance of unreliable airspeed. You would have a number of warnings that don't immediately or intuitively give the impression of a pitch trim problem."
Muilenburg said Monday that Boeing can make improvements to the MCAS and the 737 Max to make it safer to fly.
"I am confident that that again will make one of the safest airplanes in the air to fly. We know this is a link in both accidents that we can break," he said.