A final accident report released Friday said Lion Air flight 610, from Indonesia's capital Jakarta to the island of Sumatra, crashed because the pilots were never told how to quickly respond to malfunctions of the Boeing 737 Max 8 jet's automated flight-control system.
The jet plunged into the Java Sea just 13 minutes after its takeoff on Oct. 29, 2018.
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Regulators criticized the design of the anti-stall system known as MCAS, which automatically pushed the plane's nose down, leaving pilots fighting for control.
Within minutes of the announcement, Boeing responded by saying it was addressing the recommendations and had redesigned the way Angle of Attack, or AoA, sensors work with MCAS.
"MCAS will now only turn on if both AoA sensors agree, will only activate once in response to erroneous AOA, and will always be subject to a maximum limit that can be overridden with the control column," Boeing said in a statement.
The report also identified various missteps prior to the crash. The aircraft, only in use for two months, had problems on its last four flights, including one the day before its fatal accident.
The Indonesian report followed another last month from U.S. federal accident investigators who concluded that Boeing and the Federal Aviation Administration underestimated how a blizzard of visual and auditory warnings would slow pilots' ability to respond quickly enough to avert crashes.
That led to the grounding of all 737 Max jets internationally and put Boeing under intense pressure to explain problems associated with the MCAS system. The aircraft still has not resumed flying.
Boeing recently reported its third-quarter earnings dropped 51% to $1.17 billion in part because it added $900 million more in costs for the Max.
"We are very angry (at Boeing) because their negligence has caused our loved ones to die," said Muhammad Asdori, 55, whose brother and nephew were killed in the Lion Air crash.
"They should have anticipated any kind of problems with adequate training for pilots who fly their planes. We were even more angry when we learned that they had only admitted their mistake when the second MAX8 plane crashed in Ethiopia."