Chilling black-box recordings from inside the doomed Ethiopian Airlines Boeing 737 Max cockpit paint a chilling picture of chaos as the pilots were bombarded by alarms and failure warnings for six minutes.
Almost immediately after roaring down the runway in Addis Ababa, a device called a stick shaker began vibrating the captain’s control column, warning him that the plane might be about to stall and fall from the sky.
Just one minute into Flight 302 to Nairobi in neighbouring Kenya, Captain Yared Mulugeta Gatechew, 29, reported that they were having flight-control problems.
Then the anti-stall system kicked in and pushed the nose of the plane down for nine seconds.
At times the captain and his co-pilot Ahmednur Mohammed, 25, were desperately heaving back in unison on their controls as they tried to keep the colossal jet from plummeting down.
Ethiopian authorities issued a preliminary report on Thursday following the March 10 crash that killed all 157 people on board which includes a minute-by-minute narrative of a black-box recording.
Instead of climbing, the plane descended slightly. Audible warnings – ‘Don’t Sink’ – sounded in the cockpit.
The pilots fought to turn the nose of the plane up, and briefly they were able to resume climbing.
But the automatic anti-stall system pushed the nose down again, triggering more squawks of ‘Don’t Sink’ from the plane’s ground-proximity warning system.
Following a procedure that Boeing reiterated after the Lion Air crash, the Ethiopian pilots flipped two switches and disconnected the anti-stall system, then tried to regain control.
They asked to return to the Addis Ababa airport, but were continuing to struggle getting the plane to gain altitude.
Then they broke with Boeing procedure and returned power to controls including the anti-stall system, perhaps hoping to use power to adjust a tail surface that controls the pitch up or down of a plane, or maybe out of sheer desperation.
One final time, the automated system kicked in, pushing the plane into a nose dive, according to the report.
A half-minute later, the cockpit voice recording ended, the plane crashed, and all 157 people on board were killed. The plane’s impact left a crater ten meters deep.
The preliminary report found that a malfunctioning sensor sent faulty data to the Boeing 737 Max 8’s anti-stall system and triggered a chain of events that ended in a crash so violent it reduced the plane to shards and pieces.
The pilots’ struggle, and the tragic ending, mirrored an October 29 crash of a Lion Air Max 8 off the coast of Indonesia, which killed 189 people.
The anti-stall system, called MCAS, automatically lowers the plane’s nose under some circumstances to prevent an aerodynamic stall.
Boeing acknowledged that a sensor in the Ethiopian Airlines jet malfunctioned, triggering MCAS when it was not needed. The company repeated that it is working on a software upgrade to fix the problem in its best-selling plane.
‘It’s our responsibility to eliminate this risk,’ CEO Dennis Muilenburg said in a video. ‘We own it, and we know how to do it.’