Ethiopian Airlines Flight 302 plunged into a field shortly after takeoff in March, killing all 157 people on board. Indonesian Lion Air Flight 610 nosedived into the sea last October, killing all 189 passengers and crew. Investigators noted “clear similarities” between both accidents.
“The full details of what happened in the two accidents will be issued by the government authorities in the final reports,” Muilenburg said in a video posted Thursday. “It’s apparent that in both flights the Maneuvering Characteristics Augmentation System, known as MCAS, activated in response to [the] erroneous angle of attack information,” he continued.
The MCAS system reads the 737 MAX’s angle of attack (the angle of the plane’s nose) through a nose-mounted sensor. If the nose drifts too far upward, it manipulates the tail to keep the plane level and avoid a stall. However, investigators and Boeing whistleblowers claim that the sensors can deliver false readings, and the system can overcompensate, throwing the aircraft into a dive.
Muilenberg’s statement comes on the same day Ethiopian investigators determined that Flight 302’s crew “had performed all the procedures, repeatedly, provided by [Boeing], but was not able to control the aircraft.” CNN, claiming to have seen the full report, described how the pilots fought the plane’s MCAS system for the entirety of the six-minute flight, but were unable to pull the plane’s nose up and regain control.
The 737 MAX 8 is grounded worldwide following the Ethiopian Airlines disaster, and Boeing is currently previewing a software update that Muilenberg said will “eliminate the possibility” of a similar accident happening again. The update will need to be approved by air regulators worldwide before the 737 MAX will take to the sky again.
A group of Boeing engineers told the Seattle Times last month that pilots were unaware of how to override the MCAS system, and Boeing has promised to rectify this too by providing “additional educational materials.” In addition, two critical safety features that could have warned pilots of an impending dive were sold as optional extras by the manufacturer. One of these – a warning light – will now be fitted as standard.
With the troubled jet grounded worldwide, attention has since focused on the Federal Aviation Administration’s certification of the jet. A Senate investigation is now focusing on examining whether the FAA’s inspectors were properly trained, and the Department of Transport is also forming a commission to review the FAA’s certification process.
In the aftermath of the most recent crash, a group of FAA and Boeing engineers claimed that the FAA delegated much of its safety review of the 737 MAX 8 to Boeing itself, and trusted the company’s conclusions. They also claimed that Boeing downplayed safety concerns involving the MCAS system to bring the jetliner to market faster.