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Comment by WalterBright | Hacker News Reader

The emergency procedure for runaway trim was the same for both aircraft types, and was not followed. After the first crash, an Emergency Airworthiness Directive was issued to all MAX pilots reiterating the procedure, which was not followed in the second crash, as well as not reacting to an overspeed warning.

Unreported by the media, there was another MAX incident before the first crash. The crew had no knowledge of MCAS, but did follow the emergency runaway trim procedure, and continued the flight and landed safely.

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"Runaway stab trim". It is a memory item, every pilot should be able to perform it from memory.

Turn off the motor, and the trim is manual. There is a crank right there in the cockpit. If it is too hard to turn, change aircraft configuration to reduce the forces required to. Pilot know how to do this. This pilot stuff, they understand the forces on the flight controls and what impacts them.

Boeing made an engineering mistake. The pilots also made an operational mistake. Unfortunately, both mistakes at the same time were fatal.

I pray that pilot training has improved. And that Boeing has made systems level changes to the aircraft that will preclude it happening in the future.

And that is how aviation becomes safer every year; at a significant cost of customers lives.

> And that is how aviation becomes safer every year; at a significant cost of customers lives.

"Significant" might be inaccurate.

It looks like FAA Part 121 accidents over the last 10 years with fatalities have been... 4. [0]

For a total of 6 fatalities.

[0] https://www.ntsb.gov/Pages/AviationQueryV2.aspx; 2018 (1 passenger fatality) https://www.ntsb.gov/investigations/Pages/DCA18MA142.aspx ; 2019 (3 crew fatalities, cargo flight) https://www.ntsb.gov/investigations/Pages/DCA19MA086.aspx and (1 passenger fatality) https://www.ntsb.gov/investigations/Pages/DCA20MA002.aspx ; 2022 (1 ramp fatality) https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/G...

That low accident rate is nigh inconceivable. It's an incredible achievement.

The fatal accident count is higher for GA, but I didn't normalize against flight hours or flights, just glanced at it.

I'm sure there's been a study somewhere that attempts to untangle all the factors that differ between commercial carriers and GA, to see which safety is most sensitive to -- continuous highly professional maintenance, highly trained and experienced crew, rigorous airliner certification regime, etc.

One of which (Atlas Flight 3591) was Pilot error:

> The probable cause of this accident was the inappropriate response by the first officer as the pilot flying to an inadvertent activation of the go-around mode, which led to his spatial disorientation and nose-down control inputs that placed the airplane in a steep descent from which the crew did not recover.

Boeing also reduced the size of the manual trim wheels, which let them become impossible to turn sooner than on previous 737s.

The electric trim switches override MCAS. This was explained in the Emergency Airworthiness Directive sent to all MAX pilots after the first crash.

Also, overspeeding the airplane makes it much harder to turn the manual trim wheel. The cockpit voice recorder on the EA flight recorded the overspeed warning horn, which the crew did nothing about (they were at full power, should have pulled the throttles back).

The LA crew restored normal trim twenty-five times before crashing. What they never did was turn it off after restoring normal trim.

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