Ethiopian report on Max 737 crash says sensor gave faulty reading

A faulty sensor reading and the activation of an anti-stall system on a Boeing 737 Max preceded the crash of an Ethiopian Airlines flight in 2019 that killed 157 people, an interim report by the government in Addis Ababa found.

Different sensors recorded plane's angle of attack 59 degrees apart, one of which triggered MCAS system

Boeing 737 Max jets sit parked in Renton, Wash., in December. An interim report into an Ethiopian Airlines crash coincided with its one-year anniversary. (Elaine Thompson/The Associated Press)

A faulty sensor reading and the activation of an anti-stall system on a Boeing 737 Max preceded the crash of an Ethiopian Airlines flight in 2019 that killed 157 people an interim report by the government in Addis Ababa found.

The crash, which left 18 Canadians dead, followed the 2018 crash of the same model of plane in Indonesia that killed 189 people and led to the grounding of Boeing's 737 Max worldwide, wiped billions off the company's value and sparked hundreds of lawsuits from bereaved families.

Monday's report identified no issues with the airline or pilots' handling of the brand new 737 Max, which crashed shortly after takeoff.

Inaccurate sensor readings activated the MCAS anti-stall system that pointed the plane's nose down as pilots struggled to right it, the report said. Moments before impact, the plane was pointing down 40 degrees and hurtling to the ground at more than 500 feet per second.

"Most of the wreckage was found buried in the ground," it said.

Nadege Dubois-Seex, who lost her husband Jonathan Seex in the Ethiopian Airlines Flight ET302 Boeing 737 Max plane crash, and her children Alexandre, left, and Antoine, right, attend a memorial ceremony Monday at the French Embassy in Addis Ababa. (Tiksa Negeri/Reuters)

The interim report bolstered the findings of Ethiopia's initial assessment, which linked the crash to a Boeing automated system. The interim report's recommendations did not include any proposed measures for Ethiopian authorities or the airline.

It said two sensors recording the plane's angle — known as the "angle of attack" or AOA — differed in readings by 59 degrees.

"Shortly after liftoff, the left and right recorded AOA values deviated. The left AOA values were erroneous and reached 74.5," the report said.

That was followed by the activation of an anti-stall system known as MCAS, which repeatedly forced the plane's nose downward because the sensor was saying it was climbing too steeply, it said.

The Ethiopian interim report contrasts with a final report into the Lion Air crash released last October by Indonesia that faulted Boeing's design of cockpit software on the 737 Max but also cited errors by airline workers and crew.

Boeing criticized for 'inadequate' training 

The Ethiopian report did not mention any errors by the pilots, merely noting they were trained, fully certified and medically cleared to fly. It criticized Boeing for "inadequate" training for pilots flying the new model because simulations did not include scenarios where MCAS was erroneously activated.

"Training should also include simulator sessions to familiarize with normal and non-normal MCAS operation. The training simulators need to be capable of simulating AOA failure scenarios," it recommended.

The report ratifies safety recommendations that are already underway, including modifications to the sensor architecture and anti-stall MCAS software. Boeing only recently endorsed the call for more costly simulator training after holding out for months in favour of computer-based training.

The U.S. House Transportation Committee on Friday faulted the country's Federal Aviation Administration's (FAA) approval of the plane and Boeing's design failures, saying the 737 Max flights were "doomed."

WATCH: The Fifth Estate on Boeing 737 crashes

In a short statement, Boeing reiterated condolences to relatives and said it looked forward to seeing full details and formal recommendations in Ethiopia's final report.

"Boeing continues to provide technical assistance in support of the investigation, at the request of and under the direction of the U.S. National Transportation Safety Board," it said.

Passengers from 33 nations had been aboard the plane and families from many nations gathered in the capital of Addis Ababa ahead of a memorial at the crash site on Tuesday.

Some welcomed the report, but others said they were too consumed by grief to read it.

"We wish the report had come earlier or after this moment as we are now in a moment of grief, and want to focus on remembering our loved ones," said Zekarias Asfaw Shankut, 42, who lost his brother. "Now it is actually a distraction."

There was no immediate comment from U.S. aviation authorities and no clear indication from Ethiopia when the final report might be released.

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  • An earlier version of this story stated that 18 Canadians died in the Lion Air plane crash in 2018. In fact, 18 Canadians died in the Ethiopian Airlines crash in March 2019.
    Mar 09, 2020 12:58 PM ET