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A crash is not due to one cause. Multiple things have to fail for this to be a problem. Blaming pilots is way too simplistic. The design of those warnings were

by bkor 6y ago

A crash is not due to one cause. Multiple things have to fail for this to be a problem. Blaming pilots is way too simplistic. The design of those warnings were highly confusing and overwhelming. Saying "oh, just have better pilots" it NOT good enough. It should be as per the Swiss cheese theory where multiple things should fail before there's a problem. Further, not hide things like MCAS, downplay the need for additional training, refuse additional training when requested, change MCAS without notifying FAA, pressure people into being quick over safe, design MCAS to rely on a sensor, have a critical system (MCAS) rely on one sensor despite this not being allowed (critical systems MUST have multiple sensor inputs), etc. But yeah, it was the pilots not reading a message. Looking back, MCAS was not a good idea. But whatever led up to MCAS might have given the 737 MAX also some other bad changes. At the moment we don't know, maybe in future it'll be "obviously aside from MCAS the 737 MAX should also have a fix for X".

WalterBright 6y ago
> A crash is not due to one cause. Multiple things have to fail for this to be a problem. You're entirely correct. > Blaming pilots is way too simplistic. Also correct, but in my opinion the pilots were one of the multiple causes of the accidents, based on the published accounts of their actions. Ignoring Emergency Airworthiness Directives is inexcusable. Ignoring EADs is a problem that should be dealt with as part of the corrective actions required by the FAA. Recall that immediately prior to the LA crash, the previous flight crew on the same airplane had the same problem, dealt with it, and landed safely. (That was also before the EAD was issued.) Let me put it another way - would you want to get on an airplane with a crew that didn't pay attention to Emergency Airworthiness Directives? I wouldn't. And yes, Boeing must fix the MCAS system. I'm not excusing Boeing's role in the accidents.
acqq 6y ago
> it was the pilots not reading a message. 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.
- WalterBright 6y ago
  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."
  - acqq 6y ago
    > 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.
    - WalterBright 6y ago
      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.

by bkor 6y ago

WalterBright 6y ago

> A crash is not due to one cause. Multiple things have to fail for this to be a problem. You're entirely correct. > Blaming pilots is way too simplistic. Also correct, but in my opinion the pilots were one of the multiple causes of the accidents, based on the published accounts of their actions. Ignoring Emergency Airworthiness Directives is inexcusable. Ignoring EADs is a problem that should be dealt with as part of the corrective actions required by the FAA. Recall that immediately prior to the LA crash, the previous flight crew on the same airplane had the same problem, dealt with it, and landed safely. (That was also before the EAD was issued.) Let me put it another way - would you want to get on an airplane with a crew that didn't pay attention to Emergency Airworthiness Directives? I wouldn't. And yes, Boeing must fix the MCAS system. I'm not excusing Boeing's role in the accidents.

acqq 6y ago

> it was the pilots not reading a message. 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.

WalterBright 6y ago
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."
- acqq 6y ago
  > 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.
  - WalterBright 6y ago
    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.