5 ms·

To be more precise, Boeing assumed that all pilots flying their aircraft would be up to the standards of the United States as opposed to the different standards

by kayfox 7y ago

To be more precise, Boeing assumed that all pilots flying their aircraft would be up to the standards of the United States as opposed to the different standards around the world.

jfim 7y ago
Has there been a documented occurrence of a US pilot encountering an MCAS failure in the US and correctly dealing with it?
- pdonis 7y ago
  Yes, there are many reported incidents from US pilots of stability trim incidents in the FAA's database which, in hindsight, were due to MCAS. The pilots couldn't identify them as such at the time because, of course, they didn't know MCAS existed. But they were able to figure out the corrective action in time to maintain safe flight. (The reports also criticize the flight manual for being inadequate.) https://www.google.com/search?client=ubuntu&channel=fs&q=us+pilots+mcas+incidents&ie=utf-8&oe=utf-8 https://www.google.com/search?client=ubuntu&channel=fs&q=us+...
  - kayfox 7y ago
    Most of those reports involved the autopilot or were while flaps were extended, which disables MCAS. The ones that did not were complaining about not being informed about MCAS and not about it actuating. There were even incidents reported as being MCAS that did not involve stabilizer trim or a 737 MAX.
    - pdonis 7y ago
      Reports like the one where the plane started descending when autopilot was engaged are still relevant because they indicate issues with the angle of attack sensor, which is also what MCAS relies on.
      - kayfox 7y ago
        AoA sensors are notoriously unreliable and Boeing should not have depended on just one.
        pdonis 7y ago
        Yes, definitely.
  - davinic 7y ago
    Also all of the US-based MAXs had the optional AoA Sensor Disagree indicator, which would instantly show the source of the issue. The international pilots were in the dark because Boeing turned a critical safety feature into a revenue stream.
    - kayfox 7y ago
      AoA Disagree was supposed to be turned on on all 737 MAXs, but it depended on AoA indication, which was an option. This was a mistake Boeing admitted to and has since corrected. Options are not all tied to fees, the process of ordering an airplane is quite complicated because of the immense amount of customization each airline does before they even pay for the aircraft. Its unclear how much this option cost, if it cost anything. The reason why AoA indication is an option is that it requires more advanced training for the pilots, some airlines provide this training and some do not. The airlines are the ultimate decider on how much training pilots will get, Boeing and the FAA can only set minimums.
      - computerex 7y ago
        Do you have any official sources to support anything you're saying? It seems unbelievable to me that Boeing would introduce MCAS, a complete flight characteristics "augmentation" system and pass it off as a standard 737 without any special training, but would only offer AoA indication as an option due to training.
- kayfox 7y ago
  As far as anyone could tell, MCAS was not encountered before in the US.
throw0101a 7y ago
Or perhaps assumed that the pilots even knew that the MCAS existed and how to override it. Part of the debate is that Boeing told the FAA and everybody else that 'no special training' for the Max series was needed; just watch a couple-hour video or somesuch.
JanSt 7y ago
My understanding is that the pilots had only about 40 seconds time to solve the problem and were trained for one hour with an iPad (not on the MCAS, but the whole 737 Max). I'm not sure whether this is a question of pilots' standards in the US vs around the world.
- kayfox 7y ago
  The general idea was that pilots would correctly recognize large amounts of undesired and uncommanded trim being runaway trim and perform the checklist to resolve that issue that they are expected to know by memory, since there is a need to execute it fast, without paging through the Quick Reference Handbook. This is not a checklist that was introduced with the 737 MAX, but one that has existed since the introduction of the 737 in 1969. I haven't gone and checked but IIRC a similar checklist exists for all Boeing jetliners and I would expect Airbus as well. In any system failure there is a chain of events that leads up to the ultimate failure, concentrating solely on Boeing's mistakes in these crashes overlooks all the other points at which they could have been averted: 1. In the Lion Air crash, there were some significant maintenance issues that lead up to the replacement for a failing AoA sensor with a used part older than the aircraft failing as well. 2. There were some significant failings in Crew Resource Management in the accident flights. 3. There appear to be issues in the pilots abilities to deal with unexpected situations. This is why simulator training exists, so that pilots can encounter unexpected issues and deal with them correctly. 4. The failure that lead to MCAS being activated also caused a whole ton of warnings to be activated, which may have been a situation Boeing was not expecting, and therefore did not put into the minimum baseline training they create. 5. The flight computer system and MCAS was implemented problematically, relying on one input because the expected control authority was very low, and then when that was not changed the system was not re-architected. 6. Boeing's designs reflect a US-centric expectation of pilots. In the US we expect pilots flying airliners to have spent at least 1500 hours flying before they can even sit in the co-pilot seat. In other parts of the world I have heard numbers as low as 240 hours, so pilot testing will need to reflect this going forward.
  - ClumsyPilot 7y ago
    > 5. 5. The flight computer system and MCAS was implemented problematically, relying on one input because the expected control authority was very low, and then when that was not changed the system was not re-architected. I like your approach: Pilot's failures caused the crash, and Boeing made an honest mistake. And you seem to think it would have been fine flying in the US. You do realise plane crashes and industrial accidents do happen in the US? A safe system assumes they are operated by humans who are not infallible, and should not go up in flames from minor issues. Otherwise we must conclude Chernobyl reactor was a perfectly fine design.
chopin 7y ago
From what I read, I'd assume that the US just got lucky.

by kayfox 7y ago

To be more precise, Boeing assumed that all pilots flying their aircraft would be up to the standards of the United States as opposed to the different standards around the world.

jfim 7y ago

Has there been a documented occurrence of a US pilot encountering an MCAS failure in the US and correctly dealing with it?

pdonis 7y ago
Yes, there are many reported incidents from US pilots of stability trim incidents in the FAA's database which, in hindsight, were due to MCAS. The pilots couldn't identify them as such at the time because, of course, they didn't know MCAS existed. But they were able to figure out the corrective action in time to maintain safe flight. (The reports also criticize the flight manual for being inadequate.) https://www.google.com/search?client=ubuntu&channel=fs&q=us+pilots+mcas+incidents&ie=utf-8&oe=utf-8 https://www.google.com/search?client=ubuntu&channel=fs&q=us+...
- kayfox 7y ago
  Most of those reports involved the autopilot or were while flaps were extended, which disables MCAS. The ones that did not were complaining about not being informed about MCAS and not about it actuating. There were even incidents reported as being MCAS that did not involve stabilizer trim or a 737 MAX.
  - pdonis 7y ago
    Reports like the one where the plane started descending when autopilot was engaged are still relevant because they indicate issues with the angle of attack sensor, which is also what MCAS relies on.
    - kayfox 7y ago
      AoA sensors are notoriously unreliable and Boeing should not have depended on just one.
      - pdonis 7y ago
        Yes, definitely.
- davinic 7y ago
  Also all of the US-based MAXs had the optional AoA Sensor Disagree indicator, which would instantly show the source of the issue. The international pilots were in the dark because Boeing turned a critical safety feature into a revenue stream.
  - kayfox 7y ago
    AoA Disagree was supposed to be turned on on all 737 MAXs, but it depended on AoA indication, which was an option. This was a mistake Boeing admitted to and has since corrected. Options are not all tied to fees, the process of ordering an airplane is quite complicated because of the immense amount of customization each airline does before they even pay for the aircraft. Its unclear how much this option cost, if it cost anything. The reason why AoA indication is an option is that it requires more advanced training for the pilots, some airlines provide this training and some do not. The airlines are the ultimate decider on how much training pilots will get, Boeing and the FAA can only set minimums.
    - computerex 7y ago
      Do you have any official sources to support anything you're saying? It seems unbelievable to me that Boeing would introduce MCAS, a complete flight characteristics "augmentation" system and pass it off as a standard 737 without any special training, but would only offer AoA indication as an option due to training.
kayfox 7y ago
As far as anyone could tell, MCAS was not encountered before in the US.

throw0101a 7y ago

Or perhaps assumed that the pilots even knew that the MCAS existed and how to override it. Part of the debate is that Boeing told the FAA and everybody else that 'no special training' for the Max series was needed; just watch a couple-hour video or somesuch.

JanSt 7y ago

My understanding is that the pilots had only about 40 seconds time to solve the problem and were trained for one hour with an iPad (not on the MCAS, but the whole 737 Max). I'm not sure whether this is a question of pilots' standards in the US vs around the world.

kayfox 7y ago
The general idea was that pilots would correctly recognize large amounts of undesired and uncommanded trim being runaway trim and perform the checklist to resolve that issue that they are expected to know by memory, since there is a need to execute it fast, without paging through the Quick Reference Handbook. This is not a checklist that was introduced with the 737 MAX, but one that has existed since the introduction of the 737 in 1969. I haven't gone and checked but IIRC a similar checklist exists for all Boeing jetliners and I would expect Airbus as well. In any system failure there is a chain of events that leads up to the ultimate failure, concentrating solely on Boeing's mistakes in these crashes overlooks all the other points at which they could have been averted: 1. In the Lion Air crash, there were some significant maintenance issues that lead up to the replacement for a failing AoA sensor with a used part older than the aircraft failing as well. 2. There were some significant failings in Crew Resource Management in the accident flights. 3. There appear to be issues in the pilots abilities to deal with unexpected situations. This is why simulator training exists, so that pilots can encounter unexpected issues and deal with them correctly. 4. The failure that lead to MCAS being activated also caused a whole ton of warnings to be activated, which may have been a situation Boeing was not expecting, and therefore did not put into the minimum baseline training they create. 5. The flight computer system and MCAS was implemented problematically, relying on one input because the expected control authority was very low, and then when that was not changed the system was not re-architected. 6. Boeing's designs reflect a US-centric expectation of pilots. In the US we expect pilots flying airliners to have spent at least 1500 hours flying before they can even sit in the co-pilot seat. In other parts of the world I have heard numbers as low as 240 hours, so pilot testing will need to reflect this going forward.
- ClumsyPilot 7y ago
  > 5. 5. The flight computer system and MCAS was implemented problematically, relying on one input because the expected control authority was very low, and then when that was not changed the system was not re-architected. I like your approach: Pilot's failures caused the crash, and Boeing made an honest mistake. And you seem to think it would have been fine flying in the US. You do realise plane crashes and industrial accidents do happen in the US? A safe system assumes they are operated by humans who are not infallible, and should not go up in flames from minor issues. Otherwise we must conclude Chernobyl reactor was a perfectly fine design.

chopin 7y ago

From what I read, I'd assume that the US just got lucky.