Anti-stall system active before Max plane crash

Indonesia's national airline plans to stick with Boeing for its next jet order

The anti-stall system on a Boeing Max 737 aircraft may have automatically activated and sent an Ethiopian Airlines plane into a fatal plunge, latest investigations showed.

The finding based on data from the plane's flight recording black boxes is tentative, according to news reports, but the Ethiopian plane's erratic flight on March 10 resembles the problem a Lion Air flight in Indonesia experienced prior to crashing last October. The two crashes killed all 346 passengers and crew on board the flights.

Last week, aircraft-maker Boeing said it had revised the plane's flight-control system and called the new software "more robust" than the initial version. But the company stressed that the upgrade did not mean the original design was inadequate.

If the nose of the Max 8 model rises, threatening a stall, the aircraft's anti-stall device－called the Maneuvering Characteristics Augmentation System, or MCAS－automatically points the nose of the plane down to gain speed.

Early evidence suggested that the Indonesia flight's pilot struggled to keep the nose of the plane up while the system automatically forced it down.

The pilot of the Ethiopian Airlines flight experienced a similar problem after the MCAS system engaged, according to news reports.

The Wall Street Journal on Saturday reported that a reconstruction of the final moments of the Ethiopian jet described by people close to the crash investigation, airline executives and pilots, "paints a picture of a catastrophic failure that quickly overwhelmed the crew". "Pitch up, pitch up!" one pilot said to the other minutes before the plane accelerated toward the ground and crashed, the newspaper reported.

The anti-stall system can be shut off by flipping a switch on the throttle console between the pilot and co-pilot.

Pilots flying the 737 Max were alerted to the anti-stall prevention system only after the Lion Air crash and saw almost no mention of it in manuals, according to news reports.

Indonesia's national airline Garuda Indonesia said it plans to stick with Boeing for its next aircraft order but seeks to renegotiate its current contract to provide for models other than the 737 Max.