An investigation by the Indonesian National Transportation Safety Committee (NTSC) found systematic design flaws in the Boeing 737 MAX and flight crew lapses caused the Lion Air disaster.

Investigators from the NTSC reportedly told the families of Lion Air Flight 610 victims that systematic design flaws and flight crew lapses were to blame for the crash of the aircraft. This comes ahead of the release of the final accident report into the crash that resulted in the deaths of 189 people on board the flight when the plane crashed into the Java Sea on 29 October.

The findings of the investigation are expected to be released within days.

Boeing was largely blamed in a synopsis of the report, presented to relatives of the victims on Wednesday, for introducing an automated system in the MAX without adequately preparing airlines and their crews about its existence or instructing them on how to override the software should it malfunction, according to The New York Times.

The report synopsis, which was delivered in slideshow format, also pointed to maintenance issues on the Lion Air aircraft.

The automated system, known as MCAS (the Manoeuvring Characteristics Augmentation System), played a role in the crash as well as the tragedy of Ethiopian Airlines Flight 302, which saw the deaths of 157 people.

MCAS was designed to help prevent stalls, but triggered erroneously on faulty data from a sensor, sending both planes into irrecoverable nose-dives. A reliance on a single angle-of-attack made MCAS more vulnerable to failure, while the sensor on Lion Air Flight 610 was incorrectly calibrated during an earlier repair, ABC News reported, citing the slides.

The automated system has been at the centre of Boeing’s ongoing endeavour to have the MAX approved to fly. Boeing has already said it would redesign the anti-stall system to rely on more than a single sensor and to help reduce pilot workload.

Boeing has also developed training updates for the 737 MAX and is working with the FAA and global civil aviation authorities to complete the remaining steps toward certification and readiness for return to service, the aircraft manufacturer said in third-quarter results report.

On Wednesday, Boeing revealed third-quarter revenue of US$19.98 billion ($29.18 billion) – down 21 per cent from its 2018 third-quarter results –, which the aircraft manufacturer said reflected lower 737 deliveries and higher defences and services volume.

“Our top priority remains the safe return to service of the 737 MAX, and we’re making steady progress,” Boeing president and CEO Dennis Muilenburg said.

“We’ve also taken action to further sharpen our company’s focus on product and services safety, and we continue to deliver on customer commitments and capture new opportunities with our values of safety, quality and integrity always at the forefront.”

Boeing reported a profit in its defence and space business, with US$7.04 billion ($10.28 billion), but reported a loss in its commercial aeroplanes unit, down 67 per cent from 2018 third-quarter results, with US$8.25 billion ($12.05 billion), and 62 commercial aeroplanes delivered (down from 190 in the third-quarter of 2018).

The aircraft manufacturer also advised that regulatory authorities around the world would determine the timing and conditions of return to service for their jurisdictions.

For purposes of the third-quarter results, the company also assumed that regulatory approval of the 737 MAX return to service will begin in the fourth quarter of 2019 and that it will gradually increase the 737 production rate from 42 per month to 57 per month by late 2020.

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