In its final report into the October 29, 2018, Lion Air crash that killed all 189 people on board, Indonesia made recommendations to Boeing, the airline, the US Federal Aviation Administration (FAA) and other agencies
Boeing, acting without adequate oversight from US regulators, failed to grasp risks in the design of cockpit software on its 737 MAX airliner, sowing the seeds for a Lion Air crash that also involved errors by airline workers and crew, Indonesian investigators found.
The fatal crash, followed less than five months by another at Ethiopian Airlines, led to a global grounding of the Boeing 737 MAX and a crisis for the world's biggest planemaker, which this week ousted its commercial airplanes chief.
In its final report into the October 29, 2018, Lion Air crash that killed all 189 people on board, Indonesia made recommendations to Boeing, the airline, the US Federal Aviation Administration (FAA) and other agencies.
A copy was seen by Reuters and it was due to be released publicly later yesterday or today, an investigator said.
Indonesian regulators criticised the design of the anti-stall system known as MCAS, which automatically pushed the plane's nose down, leaving pilots fighting for control.
"The design and certification of the MCAS did not adequately consider the likelihood of loss of control of the aircraft," the report said.
Boeing has been working on a redesign of MCAS although it has yet to certified by the FAA.
The report also said "deficiencies" in the flight crew's communication and manual control of the aircraft contributed to the crash, as did alerts and distractions in the cockpit.
The accident had been caused by a complex chain of events, Indonesian air accident investigator Nurcahyo Utomo told reporters at a news conference, repeatedly declining to be drawn on providing a single dominant cause.
"From what we know, there are nine things that contributed to this accident," he said. "If one of the nine hadn't occurred, maybe the accident wouldn't have occurred."
During the flight, the first officer was unable to quickly identify a checklist in a handbook or perform tasks he should have had memorized, it said, adding that he had also performed poorly in training exercises.
The captain did not properly brief the first officer when handing over control just before the plane entered a fatal dive, it also said.
The report noted that according to the cockpit voice recorder, the first officer told the captain the flight was not in his initial schedule and he had been called at 4am to be informed of the revision, while the captain said he had the flu.
A critical angle of attack (AOA) sensor providing data to the MCAS anti-stall system had been miscalibrated by a company in Florida and that there were strong indications that it was not tested during installation by Lion Air maintenance staff, the report said.
Lion Air should have grounded the jet following faults on earlier flights, it said, and added that 31 pages were missing from the airline's October maintenance logs.