Investigators in Indonesia have concluded that design flaws and US oversight lapses played a major role in the crash of Lion Air's Boeing 737 Max jet in October 2018 that killed everyone onboard.
The draft results, which will be the first formal government report finding fault, will also identify a series of pilot errors and maintenance mistakes as causal factors of the Boeing jet that fell into the Java Sea, the Wall Street Journal reported.
A Boeing spokesman said the US planemaker continues offer support to the Indonesian authorities as they complete their report.
The 737 Max narrowbody, Boeing's most profitable jet and workhorse of airlines, has been grounded since March after the model was involved in two fatal crashes in Indonesia and Ethiopia within a span of five months that killed 346 people and caused disruptions across the aviation industry. Indonesia's final crash investigation report is expected to be released in early November, according to the head of transport safety committee Soerjanto Tjahjono.
US air crash investigators are preparing to make public a handful of separate safety recommendations, ranging from bolstering pilots' manual flying skills to enhancing the US aviation regulator's vetting of new aircraft designs, the Journal said.
Erroneous data from the Max's automated flight control system, known as MCAS, led the Lion Air plane to nose dive and was also identified as the culprit behind the crash of an Ethiopian Airlines jet in March shortly after take-off from Addis Ababa.
Around the end of September, the US National Transportation Safety Board (NTSB) is expected to call for improvements to cockpit training and crew decision-making, the Journal said. The NTSB is also expected to recommend a re-evaluation of the US Federal Aviation Administration's (FAA) procedures for the certification of new aircraft. The goal is to make approvals on safety matters more transparent, with more consistent federal oversight across onboard systems.
US and Indonesian recommendations will not be binding on the FAA.
The agency said it welcomes the independent reviews, will carefully consider their results and doesn’t have a firm timetable for allowing Max jets return to service.
The FAA is scheduled to meet Monday in Montreal with dozens of global aviation regulators to provide a closed-door update on anticipated fixes to the MAX’s flight-control software.
The latest version of Indonesia's accident report has been shared with the FAA and NTSB for comment, according to the Journal.
