Investigators in the Boeing 737 MAX crash in Ethiopia reached a preliminary conclusion that an anti-stall system was activated before the aircraft hit the ground, the Wall Street Journal reported, citing people briefed on the matter.
US safety investigators reviewed data from the “black boxes” aboard Ethiopian Airlines Flight 302, four people briefed on the investigation told Reuters. A preliminary report is expected as early as next week, the US officials said.
The plane crashed on March 10 shortly after taking off from Addis Ababa.
Investigators of another 737 MAX crash in Indonesia last October also focused on the anti-stall system, called MCAS. Boeing said a planned software fix would prevent repeated operation of the system at the centre of safety concerns.
Boeing’s fastest-selling 737 MAX jet, with orders worth more than $500 billion at list prices, has been grounded globally by the Federal Aviation Administration (FAA) and other regulators. Airlines are still allowed to fly them without passengers to move aircraft to other airports.
The manufacturer said it developed a training package 737 MAX pilots are required to take before the worldwide ban can be lifted, proposing as it did before the two crashes that pilots do not need flight simulator time to safely operate the aircraft.
On Thursday, a lawsuit against Boeing was filed in Chicago federal court by the family of Jackson Musoni, a Rwandan citizen, who died in the Ethiopian Airlines crash.
The lawsuit alleges Boeing defectively designed the automated flight control system. Boeing could not comment on the lawsuit.
The amount and quality of training Boeing and airlines provided to 737 MAX pilots is one issue under scrutiny as investigators around the world try to determine the causes of two 737 MAX crashes within five months.
The US Department of Justice is investigating Boeing’s development process and what Boeing disclosed about MCAS.
The US Transportation Department said a new blue ribbon commission will review how the Federal Aviation Administration certifies new aircraft.
US and European regulators knew at least two years before the Indonesian crash the normal method for controlling the 737 MAX’s nose angle might not work in conditions similar to those in two recent disasters, Reuters reported, citing a document.
The European Aviation and Space Agency (EASA) certified the airliner as safe in part because it said additional procedures and training would “clearly explain” to pilots “unusual” situations in which they would need to manipulate a rarely used manual wheel to control, or “trim,” the plane’s angle.
Those situations were not listed in the flight manual, according to an American Airlines copy seen by Reuters. Boeing declined to comment on the EASA document.