Boeing anti-stall software forced down the nose of a doomed Ethiopian jet even after pilots had turned it off, sources told Reuters on Wednesday, as investigators scrutinize the role played by technology and crew in the fatal March 10 crash.
A preliminary Ethiopian report into the disaster is due to be published within days and may include evidence the software system kicked in as many as four times before the 737 MAX dived into the ground, two people with knowledge of the matter said.
A third person familiar with the findings confirmed the software had fired up again after pilots had initially switched it off, but said there was only one significant episode in which the plane pointed itself lower in the moments before the crash.
The so-called MCAS software is at the centre of accident probes in both the crash of Ethiopian flight 302 and a Lion Air accident in Indonesia five months earlier that together killed 346 people.
It was not immediately clear whether the Ethiopian crew chose to re-deploy the system, which pushes the Boeing 737 MAX downwards to avoid stalling. But one of the sources said investigators were studying the possibility that the software started working again without human intervention.
In a statement on media reports about the investigation, Boeing said: “We urge caution against speculating and drawing conclusions on the findings prior to the release of the flight data and the preliminary report.”
Ethiopian investigators were not available for comment.
The Ethiopian crash led to a global grounding of 737 MAX jets and scrutiny of its certification process. Initial results of the accident investigation are due within days.
