Investigators: Anti-stall system activated before Ethiopian Airlines crash

An anti-stall system was activated on a Boeing 737 MAX aircraft before the plane crashed killing 157 people in Ethiopia, investigators have reportedly concluded.

The Wall Street Journal reported on Friday, citing people briefed on the matter, said the preliminary findings from the "black box" recorders were subject to revisions and that a preliminary report from Ethiopian investigators was expected within days.

The plane crashed on March 10 shortly after take-off from Addis Ababa.

The investigation of the crash of a 737 MAX aircraft in Indonesia in October has focused on the new anti-stall system, called Maneuvering Characteristics Augmentation System (MCAS), the newspaper reported.

According to a preliminary report from Indonesia investigators released in November, the MCAS on the Lion Air flight was repeatedly pushing the plane's nose down due to erroneous sensor information. 

The two crashes, barely five months apart, claimed a total of 346 lives.

On Wednesday, Boeing said a planned software fix would prevent repeated operation of the system that is at the center of safety concerns.

US and European regulators knew at least two years before a Lion Air crash that the usual method for controlling the Boeing 737 MAX’s nose angle might not work in conditions similar to those in two recent disasters, a document shows, Reuters reported on Friday. 

The European Aviation and Space Agency (EASA) certified the plane as safe in part because it said additional procedures and training would “clearly explain” to pilots the “unusual” situations in which they would need to manipulate a rarely used manual wheel to control, or “trim,” the plane’s angle. 

Those situations, however, were not listed in the flight manual, according to a copy from American Airlines seen by Reuters. 

The undated EASA certification document, available online, was issued in February 2016, an agency spokesman said.