[dTal]

>The pilots were not trained properly in emergency procedures with the stab trim. Boeing put out an Emergency Airworthiness Directive after the first crash with explicit instructions on how to deal with it, but the EA pilots did not follow those instructions.

If the planes are still crashing after the "problem" was fixed, then that wasn't the problem.

(Specifically - the "emergency procedures" in question are "what to do if your plane randomly decides to fly you into the ground". The only way to save your skin is to take a specific emergency action within a time window of a few seconds. This is not a reasonable design.)

[WalterBright]

Neither crash was within a few seconds. The EA crew fought it for 5 minutes, the LA crew 25 minutes.

-- Aviation Week, Sep 1, 2019

As for being an emergency, yes it was, and dealing with emergencies is most of pilot training. Dealing with runaway trim (which is how this failure exhibited) is part of that training. The Emergency Airworthiness Directive reiterated what the procedure was for runaway trim.

Runaway trim is so serious that it is a "memory item" meaning the pilots know how to deal with it without needing to consult a checklist.

While runaway trim should never happen, it is reasonable to expect the pilots to deal with it properly.

[dTal]

>Neither crash was within a few seconds

That's not what I said.

If you don't take mitigating actions within a time window of a few seconds, you are locked into an unrecoverable situation - however long you might fight it afterwards.

Specifically - the trim wheel is too stiff to correct if the stabilizer is loaded, so if the MCAS is allowed to wind the stabilizer to its extreme position, the pilot must - after disabling the MCAS (and therefore also the electric trim) - unload the control column to correct the situation, which will send the aircraft straight into the ground. Hence the undulations seen in the flight paths of the crashed aircraft.

The MCAS was designed under the assumption that pilots would respond to unexpected activation within 3 seconds:

https://www.seattletimes.com/seattle-news/times-watchdog/the...

[WalterBright]

The Seattle Times hasn't a good track record of accurately reporting the facts on aviation stories. Their aviation reporter does not read or comprehend his cited sources.

The EA crew dealt with the situation for 5 minutes, the LA crew for 25 minutes. Both crews used the electric trim switches to restore normal trim, multiple times. The trim switches are on the control column right under one's thumb. All the reports saying it was impossible or unreasonable or there wasn't enough time to do this are false, as both crews did it.

I strongly recommend a more reputable source, like Aviation Week 19-Sep-2019. Also an original source,

https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA...

There's also an often-cited article going around that's written by a Cessna pilot. His opinions on how jet aircraft should be designed have little to do with reality - high altitude high speed jets are very, very different from a low and slow Cessna. (The Air Force thought it would be easy to transition their experienced propeller pilots to jets. A lot of crashes and dead pilots changed their minds.)