The reasoning behind last year's fatal Lion Air Flight 610 crash which killed all 189 people onboard has been revealed as largely being down to the design of the Boeing 737 MAX and pilot error, an Indonesian regulators report stated.
The Indonesian regulators criticised the design of the anti-stall system known as MCAS - this caused the plane's nose to be pushed down automatically leaving pilots fighting for control.
The regulators also cited 89 significant findings, Bloomberg reports, including certification failures by regulators. The 353-page report suggests that a crucial sensor which had been bought from a repair shop in Florida, had not been properly tested.
"From what we know, there are nine things that contributed to this accident," Indonesian air accident investigator Nurcahyo Utomo told reporters at a news conference. "If one of the nine hadn't occurred, maybe the accident wouldn't have occurred."
The findings by Indonesian regulators come at an awkward time for Boeing who revealed that production costs for the 737 MAX rose by $900 million in the third quarter, this is in addition to the $2.7 billion in extra costs it announced earlier this year.
During the results, the company also said it will cut production of its flagship Dreamliner, and delay the arrival of a successor to its 777 mini-jumbo.
Boeing is still reiterating that it still expects the MAX to get approval from regulators such as the US Federal Aviation Administration (FAA) to fly again before the end of the year.
Boeing said it has redesigned the way Angle of Attack (AoA) sensors work with the Maneuvering Characteristics Augmentation System (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 the coming months, Boeing faces several investigations by regulators over its development of the 737 MAX- it's best selling plane of all time.