11:20 a.m. ET, April 4, 2019
There are significant similarities between Ethiopian Airlines and Lion Air crashes, report shows
The preliminary report on the Ethiopian Airlines 737 MAX accident that killed all 157 on board, shows significant similarities to the Lion Air accident, with the plane’s computer system pushing the nose down four times into a steep 40-degree dive.
About the report: The report has not yet been publicly released, but CNN obtained a copy of the report today. The preliminary report does not come to a finding of probable cause. A final report could take as long as a year to produce.
More details: The similarities between the crashes extend to maintenance and flight issues such as “temporary erratic airspeed and altitude fluctuations.”
As in the Lion Air accident, the left angle of attack indicator, the sensor that drives the Maneuvering Characteristics Augmentation System (or MCAS), recorded an incorrect reading that differed from the right angle of attack indicator by about 20 degrees.
One key difference between the two accidents: The Ethiopian pilots correctly diagnosed the issue and effectively disabled the MCAS system about three minutes before the crash.
They then tried to manually adjust the trim, but found it was “not working.”
About five minutes after takeoff, air traffic controllers granted the pilots’ request to return to the airport.
The last input recorded by the flight data recorder: The plane reaching 500 knots.