5 ms·

I suspect it's that initially, pilots believe MCAS is doing the right thing. It's only after things get really bad can they potentially realize the MCAS is the

I suspect it's that initially, pilots believe MCAS is doing the right thing. It's only after things get really bad can they potentially realize the MCAS is the problem. After all, the AoA disagree warning wasn't installed on all planes. If all your sensors and automation are telling your the plane is in danger of stalling, how can you determine they're all incorrect?

WalterBright 7y ago
Yet they all knew about the MCAS failure after the Lion Air crash. How could they not? It was in the newspapers constantly. If I was an MCAS pilot, I would have been intensely interested in the Lion Air crash, if only to be damn sure it wouldn't happen to me.
- linuxftw 7y ago
  Well, the second crash pilots did figure it out. They didn't have altitude to nose-down the plane to unload the trim, so they couldn't successfully manually trim the plane. I think there were also some airspeed indicator problems as well, but I haven't seen that reported in a while. Check out the altitude graphic here [1]. It must have been absolutely terrifying, I doubt many of us have the nerves of steel to react so quickly and correctly in such a situation. [1] https://graphics.reuters.com/ETHIOPIA-AIRPLANE/0100911Q1DX/index.html https://graphics.reuters.com/ETHIOPIA-AIRPLANE/0100911Q1DX/i...
  - WalterBright 7y ago
    They didn't need to manually trim it: 1. set the electric trim switches to nose up 2. enable the trim via the cutoff switches 3. wait until correct trim is established 4. cut off the trim via the cutoff switches > I doubt many of us have the nerves of steel to react so quickly and correctly in such a situation Indeed. That's why, if I was an MCAS pilot, I would have carefully read the reports on what went wrong, what went right with the previous LA flight, how the trim system worked, and what I needed to do if it happened to me. It's my own life at stake. I don't understand not doing this. My father used to do acrobatic formation flying with the Air Force. The idea for everyone but the lead is to concentrate on the wingtip of the adjacent airplane and track it. There were incidents where the lead would fly into the ground and the rest of the formation would fly in, too. Against orders, my dad said he'd be damned if the lead would fly him into the ground, and would keep one eye on the wingtip and the other on the ground. He died as a very old man. You might also want to read Chuck Yeager's biography. In it he makes a point of not just following checklists, but learning how the airplane systems worked. Saved his life many times. Yeager's still alive, and has buried many of his colleagues who took shortcuts.
    - linuxftw 7y ago
      Interesting you use the military as a reference point here for responding in critical situations. The military trains exhaustively so responses to critical situations are reflexive. Fortunately, your father was a pilot, and not a grunt. When you're told to storm the beach, you storm the beach, doesn't matter if it means certain death for you, it's not about you, it's about taking the beach. The pilots could have also had this reflex training on the effected systems, but Boeing and the regulators decided not to bother with training, and the training they did have was inadequate because Boeing's system was fatally flawed. > They didn't need to manually trim it: This procedure you outlined goes directly in the face of Boeing's guidance to 'follow the procedure for runaway trim'. Since the system wasn't documented at all, I assume people would trust that the procedure should work. It's not until the plane is diving into the ground due to uncorrectable trim did they discover the procedure was going to get them killed.
      - WalterBright 7y ago
        The EA pilots followed the procedure, and when it didn't work they went off procedure (i.e. they turned the stab trim system back on) which led to the final plunge. If they had used the trim switches after turning the system back on, it would have corrected the nose down. It seems the natural thing to do. Why didn't they? I do not know, and none of the accounts I've read addressed this. I suspect that will be a crucial point in the NTSB's report. Your assessment about pilots not being ordered to their deaths is incorrect. My father served as a navigator on B-17s in WW2. He was ordered to fly 30 missions. At the time, the 30 mission survival rate was 20%, as bad as any beach assault. The aircrews knew this, and it put a terrible strain on them. But they went anyway. My father told me he was convinced he was going to die, made peace with it, and simply decided to do the best job he could before he bought it. The Luftwaffe pilots had it even worse. There was no 30 mission maximum. It was fly until you die. Not many survived.
        linuxftw 7y ago
        > Why didn't they? I do not know, and none of the accounts I've read addressed this. I've wondered the same thing. My assumption is that the MCAS disables the input of the trim switches used by the pilots when it's active. We know that MCAS resets itself after certain conditions and 'forgets' what it did previously to override it's intended maximum authority. It's also be stated that the MCAS is 'reset' when the pilot uses the trim switches, but I would think that this would have been abundantly apparent as well: press switch, nose stops going down, unless they just did not notice the trim being activated in the first place (which based on other people's accounts, that would be hard to miss due to a giant wheel). > Your assessment about pilots not being ordered to their deaths is incorrect. My father served as a navigator on B-17s in WW2. He was ordered to fly 30 missions. At the time, the 30 mission survival rate was 20%, as bad as any beach assault. Fair enough, that does sound pretty brutal. My point was more about the reflexive training to overcome fear to function. It might be impossible to think critically in such a moment for most people, thus the goal is to put people on 'autopilot' when they encounter a specific scenario. But, WW2 was USAAF, USAF didn't exist yet, so no way for me to get that context ;)
  - treis 7y ago
    >Check out the altitude graphic here [1]. It must have been absolutely terrifying That graph is based on faulty FlightAware data. According to the preliminary report they were at 7,000 feet AGL and climbing when they re-enabled the electric trim.

WalterBright 7y ago

Yet they all knew about the MCAS failure after the Lion Air crash. How could they not? It was in the newspapers constantly. If I was an MCAS pilot, I would have been intensely interested in the Lion Air crash, if only to be damn sure it wouldn't happen to me.

linuxftw 7y ago
Well, the second crash pilots did figure it out. They didn't have altitude to nose-down the plane to unload the trim, so they couldn't successfully manually trim the plane. I think there were also some airspeed indicator problems as well, but I haven't seen that reported in a while. Check out the altitude graphic here [1]. It must have been absolutely terrifying, I doubt many of us have the nerves of steel to react so quickly and correctly in such a situation. [1] https://graphics.reuters.com/ETHIOPIA-AIRPLANE/0100911Q1DX/index.html https://graphics.reuters.com/ETHIOPIA-AIRPLANE/0100911Q1DX/i...
- WalterBright 7y ago
  They didn't need to manually trim it: 1. set the electric trim switches to nose up 2. enable the trim via the cutoff switches 3. wait until correct trim is established 4. cut off the trim via the cutoff switches > I doubt many of us have the nerves of steel to react so quickly and correctly in such a situation Indeed. That's why, if I was an MCAS pilot, I would have carefully read the reports on what went wrong, what went right with the previous LA flight, how the trim system worked, and what I needed to do if it happened to me. It's my own life at stake. I don't understand not doing this. My father used to do acrobatic formation flying with the Air Force. The idea for everyone but the lead is to concentrate on the wingtip of the adjacent airplane and track it. There were incidents where the lead would fly into the ground and the rest of the formation would fly in, too. Against orders, my dad said he'd be damned if the lead would fly him into the ground, and would keep one eye on the wingtip and the other on the ground. He died as a very old man. You might also want to read Chuck Yeager's biography. In it he makes a point of not just following checklists, but learning how the airplane systems worked. Saved his life many times. Yeager's still alive, and has buried many of his colleagues who took shortcuts.
  - linuxftw 7y ago
    Interesting you use the military as a reference point here for responding in critical situations. The military trains exhaustively so responses to critical situations are reflexive. Fortunately, your father was a pilot, and not a grunt. When you're told to storm the beach, you storm the beach, doesn't matter if it means certain death for you, it's not about you, it's about taking the beach. The pilots could have also had this reflex training on the effected systems, but Boeing and the regulators decided not to bother with training, and the training they did have was inadequate because Boeing's system was fatally flawed. > They didn't need to manually trim it: This procedure you outlined goes directly in the face of Boeing's guidance to 'follow the procedure for runaway trim'. Since the system wasn't documented at all, I assume people would trust that the procedure should work. It's not until the plane is diving into the ground due to uncorrectable trim did they discover the procedure was going to get them killed.
    - WalterBright 7y ago
      The EA pilots followed the procedure, and when it didn't work they went off procedure (i.e. they turned the stab trim system back on) which led to the final plunge. If they had used the trim switches after turning the system back on, it would have corrected the nose down. It seems the natural thing to do. Why didn't they? I do not know, and none of the accounts I've read addressed this. I suspect that will be a crucial point in the NTSB's report. Your assessment about pilots not being ordered to their deaths is incorrect. My father served as a navigator on B-17s in WW2. He was ordered to fly 30 missions. At the time, the 30 mission survival rate was 20%, as bad as any beach assault. The aircrews knew this, and it put a terrible strain on them. But they went anyway. My father told me he was convinced he was going to die, made peace with it, and simply decided to do the best job he could before he bought it. The Luftwaffe pilots had it even worse. There was no 30 mission maximum. It was fly until you die. Not many survived.
      - linuxftw 7y ago
        > Why didn't they? I do not know, and none of the accounts I've read addressed this. I've wondered the same thing. My assumption is that the MCAS disables the input of the trim switches used by the pilots when it's active. We know that MCAS resets itself after certain conditions and 'forgets' what it did previously to override it's intended maximum authority. It's also be stated that the MCAS is 'reset' when the pilot uses the trim switches, but I would think that this would have been abundantly apparent as well: press switch, nose stops going down, unless they just did not notice the trim being activated in the first place (which based on other people's accounts, that would be hard to miss due to a giant wheel). > Your assessment about pilots not being ordered to their deaths is incorrect. My father served as a navigator on B-17s in WW2. He was ordered to fly 30 missions. At the time, the 30 mission survival rate was 20%, as bad as any beach assault. Fair enough, that does sound pretty brutal. My point was more about the reflexive training to overcome fear to function. It might be impossible to think critically in such a moment for most people, thus the goal is to put people on 'autopilot' when they encounter a specific scenario. But, WW2 was USAAF, USAF didn't exist yet, so no way for me to get that context ;)
- treis 7y ago
  >Check out the altitude graphic here [1]. It must have been absolutely terrifying That graph is based on faulty FlightAware data. According to the preliminary report they were at 7,000 feet AGL and climbing when they re-enabled the electric trim.