Indonesia has recommended closer scrutiny of automated control systems, better design of flight deck alerts and accounting for a more diverse pilot population in the wake of a Boeing 737 MAX crash, according to a copy of a final report seen by Reuters.
The report into the crash of the Lion Air jet, Oct. 29, 2018, that killed all 189 people on board is to be released publicly later Friday.
Less than five months after the Lion Air accident, an Ethiopian Airlines 737 MAX crashed, leading to a global grounding of the model and sparking a corporate crisis at Boeing, the world's biggest plane manufacturer.
Indonesian investigators Wednesday told families of the victims that a mix of factors contributed to the crash, including mechanical and design issues and a lack of documentation about how systems would behave.
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, according to slides presented to the families.
The final report said the first officer was unfamiliar with procedures and had shown issues handling the aircraft during training.
The report also found that a critical sensor providing data to an anti-stall system had been miscalibrated by a repair shop in Florida and that there were strong indications that it was not tested during installation by Lion Air maintenance staff.
Lion Air should have grounded the jet following faults on earlier flights, the report said and added that 31 pages were missing from the airline's October maintenance logs.
Lion Air did not respond to a request for comment.
Boeing issued a statement after Indonesia's National Transportation Safety Committee released its final report on the accident.
Boeing's President and CEO Dennis Muilenburg said said the company is addressing the committee's safety recommendations and working to enhance the safety of the 737 Max jet to prevent the flight control conditions that occurred in the accident from ever happening again.
Muilenburg said the aircraft and its software are receiving an unprecedented level of global regulatory oversight, testing and analysis. This includes hundreds of simulator sessions and test flights, regulatory analysis of thousands of documents, reviews by regulators and independent experts and extensive certification requirements.
In the report, Indonesian regulators recommended a redesign of the anti-stall system known as MCAS that automatically pushed the plane's nose down, leaving pilots fighting for control.
Boeing has said it would remake the system and provide more information about it in pilot manuals.
According to the report, Boeing's safety assessment assumed pilots would respond within three seconds of a system malfunction but on the accident flight and one that experienced the same problem the prior evening, it took both crews about eight seconds to respond.
Boeing has said it cannot comment before the release of the report.
A panel of international air safety regulators this month also faulted Boeing for assumptions it made in designing the 737 MAX and found areas where Boeing could improve processes.
Source: Voice of America