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The pilots of Lion Air 610 had in excess of 5000 hours. Flight experience doesn't answer the question I asked either. The assertion was made that U.S. pilots re

by cmurf 8y ago

The pilots of Lion Air 610 had in excess of 5000 hours. Flight experience doesn't answer the question I asked either. The assertion was made that U.S. pilots received difference training (NG vs MAX). What difference training? You assume without evidence the problem manifests like runaway trim. And then proceed to assume without evidence the incompetency of two pilots. And yet you refuse to assume the incompetency of the automation, which didn't mere fail, it countermanded with lethal force the 100% correct control inputs of the pilots. The idea they have to assert their sanity by flipping two switches, is about as ridiculous as automation not having to assert its sanity when it, by design, trusts a single point of failure one upping that by trusting it while it's failing and one upping that to extreme by taking action on it without any regard to other input sources including the pilots themselves. It's beyond obscene to me. I have personally trained private pilots with competency at identifying failed gauges, knowing which one to disregard, and estimating the missing values by inference from the remaining gauges. And this is in sub-200 hour pilots. The skill required for the instrument rating exceeds this particular automation in the AOA failure case by quite a lot. And the skill required for commercial and ATP ratings is even greater than that by quite a lot. Meanwhile MCAS upset from judgement of a single sensor induced such an unusual attitude it became unrecoverable. So the assumption of incompetency by pilots, while cutting automation all kinds of slack is to me 180 degrees backwards.

DuskStar 8y ago
I think I misread difference training as different training there, my apologies. And the Ethiopian Air copilot had ~200 total hours, thus the comment. > You assume without evidence the problem manifests like runaway trim. And then proceed to assume without evidence the incompetency of two pilots. And yet you refuse to assume the incompetency of the automation, which didn't mere fail, it countermanded with lethal force the 100% correct control inputs of the pilots. The idea they have to assert their sanity by flipping two switches, is about as ridiculous as automation not having to assert its sanity when it, by design, trusts a single point of failure one upping that by trusting it while it's failing and one upping that to extreme by taking action on it without any regard to other input sources including the pilots themselves. It's beyond obscene to me. I didn't say that it manifests like runaway trim. I said that it manifests as "severely outside the norm trim", which it most certainly does. Unless you're saying that full nose down trim is normal? As for "asserting incompetence without evidence", they're certainly less competent than pilot #3 on the Lion Air flight the night before. (since, you know, that guy realized what was going on and how to resolve it) As for the automation being incompetent, yep you're right! It is! But airplane crashes don't happen for one reason - not commercial flights at least. They happen when a sequence of failures occurs, just like here. Boeing failed to consider the worst case behavior of MCAS, Lion Air maintenance fucked up, and the Lion Air pilots weren't able to diagnose the failure that morning. (The failure pipeline of the Ethiopian crash is still to be determined) As for why Boeing failed there... It's at least partly because the automatic trim controls weren't considered a safety critical part, since they had multiply redundant backups. It's just that the backups were "turn off electronic trim" and "grab the trim wheel and hold it in place", both of which require pilot action. (Allowing stuff like this to get grandfathered in is arguably a hole in the FAA's systems) > I have personally trained private pilots with competency at identifying failed gauges, knowing which one to disregard, and estimating the missing values by inference from the remaining gauges. And this is in sub-200 hour pilots. The skill required for the instrument rating exceeds this particular automation in the AOA failure case by quite a lot. And the skill required for commercial and ATP ratings is even greater than that by quite a lot. Meanwhile MCAS upset from judgement of a single sensor induced such an unusual attitude it became unrecoverable. Well then why was the issue so difficult for the pilots to diagnose here? There's a gauge for trim, and I'd hope it would be looked at when trying to figure out why you have to keep pulling back on the yoke so hard.
- bushido 8y ago
  I am not a pilot. But based on my understanding the activation of nose down due to MCAS doesn't present itself like the standard runaway trim that pilots are trained on. Trained Behaviour: - In case of continuous trim - perform yoke jerk to disable the automatic trim (per previous 737 models) - turn off electronic trim - grab the trim wheel and hold it in place --------------- MCAS Behaviour: - On nose down event, pilots pitch the flight up, adjust trim - Which disables MCAS for 5 seconds - No continuous trim event manifests --------------- From what I've read on some pilot forums, Boeing made a few errors: - Removed "Yoke Jerk" - The 5 second delay removed the continuous trim conditions - Didn't sufficient train pilots on this condition i.e. intermittent automatic trim - Pilots did not see the behavior that they were trained for in the few seconds between each nose down event
  - DuskStar 8y ago
    > From what I've read on some pilot forums, Boeing made a few errors: I'll agree with #2-4, but #1 was the entire point of MCAS - to reduce the response of the aircraft to pulling back on the yoke in high AOA situations. Disabling MCAS when pulling back on the yoke would thus make the aircraft less safe, and cause it to (rightly) fail certification.
- cmurf 8y ago
  >it manifests as "severely outside the norm trim", which it most certainly does How do you know it manifests as trim at all? How do you know it's not an elevator problem? But you're certain, gotcha. >they're certainly less competent than pilot #3 The pilot who wasn't flying, because he couldn't fly, was in a position to watch the scene unfold and happened to be the only person with both the trim wheel and yoke toggle in his field of view? Are you aware most airlines with four crew for international flights require all of them in the cockpit for takeoff and landing expressly to aid in CRM? If two high hour pilots are all that's needed, why require four? Sometimes in an emergency a different perspective might be useful? But again you're certain. >Boeing failed to consider the worst case behavior of MCAS Not in evidence. >Lion Air maintenance fucked up Not in evidence. >Lion Air pilots weren't able to diagnose the failure that morning We don't know how far along they got. The first step in commanded pitch, roll, yaw, or power changes is reaction based on training, not diagnoses. The plane must be stabilized to buy time to conduct a diagnosis. There's circumstantial evidence of startle factor which can be a considerable inhibitor to diagnosing anything. >Well then why was the issue so difficult for the pilots to diagnose here? I have no certainty based on the available evidence. That's the point. What we know is, they were expressly not trained on any differences between the prior model and the one they were flying, let alone the existence of MCAS or MCAS upset. And many U.S. based pilots who fly MAX and found out years after the fact for the first time of its existence and function were pissed that it took an accident to learn about it. Why would U.S. pilots be pissed if this "certainly" manifests in such a familiar manner that there'd be no difficulty, no delay, and no worry whatsoever, and that U.S. pilots would have easily recovered from the identical scenario?

by cmurf 8y ago

DuskStar 8y ago

I think I misread difference training as different training there, my apologies. And the Ethiopian Air copilot had ~200 total hours, thus the comment. > You assume without evidence the problem manifests like runaway trim. And then proceed to assume without evidence the incompetency of two pilots. And yet you refuse to assume the incompetency of the automation, which didn't mere fail, it countermanded with lethal force the 100% correct control inputs of the pilots. The idea they have to assert their sanity by flipping two switches, is about as ridiculous as automation not having to assert its sanity when it, by design, trusts a single point of failure one upping that by trusting it while it's failing and one upping that to extreme by taking action on it without any regard to other input sources including the pilots themselves. It's beyond obscene to me. I didn't say that it manifests like runaway trim. I said that it manifests as "severely outside the norm trim", which it most certainly does. Unless you're saying that full nose down trim is normal? As for "asserting incompetence without evidence", they're certainly less competent than pilot #3 on the Lion Air flight the night before. (since, you know, that guy realized what was going on and how to resolve it) As for the automation being incompetent, yep you're right! It is! But airplane crashes don't happen for one reason - not commercial flights at least. They happen when a sequence of failures occurs, just like here. Boeing failed to consider the worst case behavior of MCAS, Lion Air maintenance fucked up, and the Lion Air pilots weren't able to diagnose the failure that morning. (The failure pipeline of the Ethiopian crash is still to be determined) As for why Boeing failed there... It's at least partly because the automatic trim controls weren't considered a safety critical part, since they had multiply redundant backups. It's just that the backups were "turn off electronic trim" and "grab the trim wheel and hold it in place", both of which require pilot action. (Allowing stuff like this to get grandfathered in is arguably a hole in the FAA's systems) > I have personally trained private pilots with competency at identifying failed gauges, knowing which one to disregard, and estimating the missing values by inference from the remaining gauges. And this is in sub-200 hour pilots. The skill required for the instrument rating exceeds this particular automation in the AOA failure case by quite a lot. And the skill required for commercial and ATP ratings is even greater than that by quite a lot. Meanwhile MCAS upset from judgement of a single sensor induced such an unusual attitude it became unrecoverable. Well then why was the issue so difficult for the pilots to diagnose here? There's a gauge for trim, and I'd hope it would be looked at when trying to figure out why you have to keep pulling back on the yoke so hard.

bushido 8y ago
I am not a pilot. But based on my understanding the activation of nose down due to MCAS doesn't present itself like the standard runaway trim that pilots are trained on. Trained Behaviour: - In case of continuous trim - perform yoke jerk to disable the automatic trim (per previous 737 models) - turn off electronic trim - grab the trim wheel and hold it in place --------------- MCAS Behaviour: - On nose down event, pilots pitch the flight up, adjust trim - Which disables MCAS for 5 seconds - No continuous trim event manifests --------------- From what I've read on some pilot forums, Boeing made a few errors: - Removed "Yoke Jerk" - The 5 second delay removed the continuous trim conditions - Didn't sufficient train pilots on this condition i.e. intermittent automatic trim - Pilots did not see the behavior that they were trained for in the few seconds between each nose down event
- DuskStar 8y ago
  > From what I've read on some pilot forums, Boeing made a few errors: I'll agree with #2-4, but #1 was the entire point of MCAS - to reduce the response of the aircraft to pulling back on the yoke in high AOA situations. Disabling MCAS when pulling back on the yoke would thus make the aircraft less safe, and cause it to (rightly) fail certification.
cmurf 8y ago
>it manifests as "severely outside the norm trim", which it most certainly does How do you know it manifests as trim at all? How do you know it's not an elevator problem? But you're certain, gotcha. >they're certainly less competent than pilot #3 The pilot who wasn't flying, because he couldn't fly, was in a position to watch the scene unfold and happened to be the only person with both the trim wheel and yoke toggle in his field of view? Are you aware most airlines with four crew for international flights require all of them in the cockpit for takeoff and landing expressly to aid in CRM? If two high hour pilots are all that's needed, why require four? Sometimes in an emergency a different perspective might be useful? But again you're certain. >Boeing failed to consider the worst case behavior of MCAS Not in evidence. >Lion Air maintenance fucked up Not in evidence. >Lion Air pilots weren't able to diagnose the failure that morning We don't know how far along they got. The first step in commanded pitch, roll, yaw, or power changes is reaction based on training, not diagnoses. The plane must be stabilized to buy time to conduct a diagnosis. There's circumstantial evidence of startle factor which can be a considerable inhibitor to diagnosing anything. >Well then why was the issue so difficult for the pilots to diagnose here? I have no certainty based on the available evidence. That's the point. What we know is, they were expressly not trained on any differences between the prior model and the one they were flying, let alone the existence of MCAS or MCAS upset. And many U.S. based pilots who fly MAX and found out years after the fact for the first time of its existence and function were pissed that it took an accident to learn about it. Why would U.S. pilots be pissed if this "certainly" manifests in such a familiar manner that there'd be no difficulty, no delay, and no worry whatsoever, and that U.S. pilots would have easily recovered from the identical scenario?