Lion Air crash report faults Boeing 737 MAX design, certification and pilot training

The findings of an Indonesian investigation put the blame on Boeing for MCAS design flaws, among others, in the fatal crash of Lion Air Flight 610.

Indonesia’s National Transport Safety Committee (KNKT) has released its final report on the Lion Air crash that killed 189 people a year ago. It found the flight was doomed by a combination of design flaws, inadequate pilot training and maintenance problems.

The report said that shortly after Flight 610 left Jakarta on 29 October, a newly replaced and incorrectly calibrated angle-of-attack (AoA) sensor that had a 21-degree bias, began sending erroneous flight information to the jet’s computer.

These included indicated airspeed, altitude and feel differential pressure, triggering an automated feature in the 737 MAX 8 that drove the plane’s nose downwards “repetitively”, according to the report. This feature was the Maneuvering Characteristics Augmentation System (MCAS).

The investigation considered that the design and certification of this feature was inadequate, while the aircraft flight manual and flight crew training did not include information about MCAS.

Lion Air Flight 610 crashed into the Java Sea on 29 October, killing all eight crew members and 181 passengers on board.

The new report highlights an established link between the crash and MCAS that emerged soon after the October 2018 disaster, which has remained at the centre of Boeing’s re-certification process for the grounded 737 MAX 8 airplane.

In a statement issued shortly after the release of the report on Friday, Boeing’s CEO and president, Dennis Muilenburg, conveyed condolences on behalf of the company to the crash victims’ families.

“We mourn with Lion Air, and we would like to express our deepest sympathies to the Lion Air family,” Muilenburg said.

“These tragic events have deeply affected us all and we will always remember what happened.”

The manufacturer says it has taken multiple steps to “prevent the flight control conditions that occurred in this accident from ever happening again”.

Boeing said it has “redesigned” the way AoA sensors work with a feature of MCAS. Going forward, the manufacturer said MCAS will compare information from both AoA sensors before activating, adding a new layer of protection.

In addition, 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 it was also “updating crew manuals and pilot training, designed to ensure every pilot has all of the information they need to fly the 737 MAX safely”.

Last week, 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 attributed to lower 737 deliveries and higher defences and services volume.

The 737 MAX has remained grounded since March, after a second fatal crash involving the jet in Ethiopia, which saw the deaths of 157 people.

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