Preliminary Report: Software malfunction caused Ethiopian Airline MAX 8 crash

Ethiopian airline crash site

In a preliminary finding, officials investigating the crash of an Ethiopian airlines Boeing 737 Max 8 believe that a flight control feature designed to prevent a stall was activated before the plane nose-dived and crashed, The Wall Street Journal reports, citing multiple unnamed sources.

The findings, based on data retrieved from the plane's black boxes, come as the family of a Rwandan passenger who died on the March 10 flight has sued Boeing, the maker of the plane, in a U.S. court.

The officials probing the crash report that the preliminary findings suggest similarities between the Ethiopian crash, which killed 157 people on takeoff from Addis Ababa, and the crash of Lion Air in Indonesia, also on takeoff, that killed 189 people six months ago.

The report tracks with a statement by Ethiopian Minister of Transport Dagmawit Moges who has said preliminary data indicated "clear similarities" between both crashes.

The emerging consensus was relayed to the Federal Aviation Administration on Thursday, one of the officials said, according to the The Journal.

The preliminary finding points to a misfiring by the same automated system, called MCAS, that occurred just prior to the crash of the Lion Air plane shortly after leaving Jakarta, the Journal says.

In the Lion Air crash, the new stall-prevention system, based on erroneous sensor information, repeatedly pushed the plane’s nose down, according to the preliminary report. The pilot was forced to battle the flight controls before losing control and plunging into the Java Sea.

Boeing this week announced changes in the MCAS system to make it less aggressive and to give pilots more control to override it if necessary. In addition, Boeing said the system will rely on data from the two angle of attack sensors, not just one.

Boeign also said that the anti-stall system would only engage once per event, instead of repeatedly forcing the plane to nose-dive.

The Journal reports that U.S. air-safety regulators have tentatively approved the Boeing software and pilot-training changes.

The lawsuit against Boeing was filed in a federal court in Chicago by the family of Jackson Musoni. It alleges that Boeing had defectively designed the automated flight control system.

The suit charged that the plane "was defective in design, had inadequate warnings, and was unreasonably dangerous."