Boeing (BA.N), 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 within 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 29 Oct, 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. 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.
During the flight, the first officer was unable to quickly identify a checklist in a handbook or perform tasks he should have had memorised, 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 4 a.m. 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 Florida-based Xtra Aerospace without the recommended equipment, the report said, and there were strong indications that it was not tested during installation by Lion Air maintenance staff.
The FAA, also faulted by the report for its oversight of Xtra, formally revoked the maintenance firm’s repair station certificate following the report’s publication. Xtra responded in a statement that it had been cooperating closely with the FAA “and though we have reached a settlement with the FAA, we respectfully disagree with the agency’s findings.”
The company noted the FAA action was separate from the Indonesia’s “investigation and report of the Lion Air Boeing 737 Max accident and is not an indication that Xtra was responsible for the accident.”
A Lion Air spokesman said the crash was an “unthinkable tragedy” and it was essential to take immediate corrective actions to ensure a similar accident never occurred again. Boeing said in a statement that it was addressing Indonesia’s safety recommendations and taking actions to enhance the safety of the 737 MAX. Saying it mourned with Lion AIR. reuters