It was that the message (see the whole, the link was quoted) definitely wasn't clear. It has multiple weasel words and it is far from a clear and actionable sequence checklist for the exact condition in which two planes were put due to the MCAS. Only with the hindsight of knowing how two accidents developed and the independent pilots trying to reconstruct on the simulators these events it can be claimed that that formulation described something usable. Just with the pilots "reading it" at that time and even having it in front of them at the moment of the accident, without any special training for that situation (where the plane multiple times "undoes" the actions of the pilot, orienting the plane toward ground as the plane is still flying low) it's still improbable that the accident wouldn't happen.
Note: It's Boeing who insisted that the training for MCAS is not needed.
It's written in airplane jargon, of course, but it's plenty clear.
> It's Boeing who insisted that the training for MCAS is not needed.
It's not completely unreasonable to expect the pilots to be able to handle runaway trim, especially given an EMERGENCY AIRWORTHINESS DIRECTIVE reiterating how to do it. Runaway trim is a critical problem, which is why the electric trim switches are there as well as the cutoff switches, all in easy reach. Dealing with this is supposed to be a "memory item", meaning something the pilots must know.
But clearly in hindsight, dealing with runaway trim must be specifically and better trained for.
> special training
The thing about runaway trim is it turns on when it's not supposed to. That's why the electric trim overrides are there and the cutoff switches. Those are there for all Boeing jets since electric trim was installed going back to at least 1960 and probably much earlier.
When I worked on the stabilizer trim system on the 757, I worked mostly on the gearbox, but was peripherally involved with the electrical system for it. The cutoff switches were there for "when demons possess the control system and try to drive you into the ground."
> The cutoff switches were there for "when demons possess the control system and try to drive you into the ground."
For the second crash it wasn't about "hit the switch" at any moment you will when you notice the problem. It was: "unless you are lucky to hit the switch in a very special moment, you won't be able to regain the control of the plane at all." Not in the message, not trained, and even some pilots learned that only later in the reconstruction of the crash on the simulator.
The EAD was quite clear. Trim back to normal with the electric trim switches, then shut off the trim.
There is nothing confusing about that. There is no "very special moment". There is no "you won't be able to regain control at all".
The proof of what I say is in the first LA incident (the one that didn't crash). The pilots trimmed back to normal a couple times with the electric trim switches, then hit the cutoff switches, and landed safely without incident.
In the second LA incident, they trimmed back to normal 25 times, never thought to cut off the trim system, and crashed on the 26th time.
> The EAD was quite clear. Trim back to normal with the electric trim switches, then shut off the trim.
I don't see that wording anywhere in EAD. Only the quoted weasel worded sentence. It's your interpretation post-crashes and their analysis that they were supposed to do exactly that in exactly that order. Or do you have some other quote? The mental model the pilots were trained to was "if the electric doesn't work, switch it off, trim manually." The MCAS changed that to: 1) electric will work, but MCAS "invisible ghost" will pause to confuse you that the controls work and only then undo whatever you managed to do. 2) There's only one position in which turning off the switch was safe, under their circumstances -- switching to manual trim outside of the "normal" was a practical death sentence, also nowhere written.
So, as far as I see, not only your "clear" sequence was nowhere written that clear, the mental model that the pilots had to have changed completely, but without training, and the safe procedure to escape was figured out only after looking at the logs of two crashes.
That it is "clear" to somebody sitting in the armchair with the crash logs and having all the time in the world to think about it after all that happened doesn't mean that those who survived had such clearness, just that they had luck.
Um, I worked on the 757 stab trim design for 3 years. I'm not an armchair quarterback here. An EAD is not a document where you look for loopholes, parse linguistics, and debate angels dancing on pinheads. Take the straightforward meaning, add it to the information a pilot already knows, and it makes perfect sense.
P.S. your version of what the words mean is solely your invention. I've shown this text to many people, and none have come close to your creative version. This includes pilots.
It was that the message (see the whole, the link was quoted) definitely wasn't clear. It has multiple weasel words and it is far from a clear and actionable sequence checklist for the exact condition in which two planes were put due to the MCAS. Only with the hindsight of knowing how two accidents developed and the independent pilots trying to reconstruct on the simulators these events it can be claimed that that formulation described something usable. Just with the pilots "reading it" at that time and even having it in front of them at the moment of the accident, without any special training for that situation (where the plane multiple times "undoes" the actions of the pilot, orienting the plane toward ground as the plane is still flying low) it's still improbable that the accident wouldn't happen.
Note: It's Boeing who insisted that the training for MCAS is not needed.