Stick-shaker response shows Ethiopian 737 Max crash crew stressed from outset: BEA

French investigators believe the crew of the Ethiopian Boeing 737 Max which crashed nearly four years ago experienced rapidly-developing stress from a stick-shaker alert on take-off, even before they found themselves fighting against the aircraft’s MCAS stabiliser-trim system. Investigation authority BEA has highlighted crew failings which began when the loss of an angle-of-attack sensor during take-off triggered the stick-shaker. BEA says the stick-shaker should have prompted the crew to apply stall-recovery procedures from memory – including applying nose-down input and disengaging the autopilot and autothrottle. “Only the nose-down input was performed by the flight crew,” it states. “The autothrottle remained engaged and the pilot later insisted on engaging the autopilot.” Engineering simulations, it says, demonstrate that the pilots would have been presented with airspeed and altitude ‘disagree’ messages, and should have run a checklist for unreliable airspeed – which also requires autopilot and autothrottle disengagement, adopting a 10° nose-up pitch and a specific thrust setting. But the Ethiopian Airlines captain did not disconnect the autothrottle and instead attempted to engage the autopilot, despite being below the autopilot height threshold set by the airline. “This premature action, although not appropriate in stick-shaker conditions, may be symptomatic of a state of stress that had been rapidly developing following the activation of the [stick-shaker] immediately after take-off,” says BEA. It says the first officer – who had just 300h experience – appears to have been “overwhelmed” by events from the point at which the stick-shaker triggered. Story has more.<br/>