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The problem was software that prioritized input from a fauly external sensor, over pilot control, and literally crashed planes directly into the ground. At a ce

The problem was software that prioritized input from a fauly external sensor, over pilot control, and literally crashed planes directly into the ground. At a certain step in the sequence it was not physically possible for a pilot to pull hard enough on the control element to counteract the software. Could they have disabled the system? Only if they could figure out the specific software trying to crash the plane. Is that what you meant by "the problem wasn't the software?" Because the pilots should have been trained to unplug the computer to stop it from crashing the plane?

ethbr1 3y ago
Pilots are definitely trained how to disable the autopilot, if needed. Afaic, the fault apportionment was Boeing documentation > airlines >> pilots > Boeing technical design.
- diabeetusman 3y ago
  Not sure why you’re bringing up autopilot— the MCAS system runs even when the autopilot is disabled. Edit: Also, how does the fault lie with the airlines? Boeing didn’t document the existence of MCAS in the flight manual or training materials.
  - ethbr1 3y ago
    Because the comment I was replying to >> Because the pilots should have been trained to unplug the computer to stop it from crashing the plane? Yes. The fault lies with the airlines because I don't for a second believe they didn't put pressure on Boeing to get the MAX certified without mandating retraining. And then once that was done, didn't dig into the details too hard about what changes were made. I have a low tolerance for 'I set up all the conditions and incentives to encourage you to break the law... but you should take all the blame when it explodes.' At some point, the customer has to take some responsibility for what they asked for.
    - actionfromafar 3y ago
      It’s easier to blame Boeing because they made the damn thing its documentation. We know for a fact they are at fault. Some or all of the airlines may or may not have put pressure on Boeing.
  - numpad0 3y ago
    Wasn't MCAS designed to activate when A/P is disconnected, also?
- acdha 3y ago
  This wasn’t related to autopilot and they removed mention of the MCAS system from the documentation to support the main selling point of the 737 MAX, which was that existing 737 pilots would be able to switch easily without recertification. They knew that they’d lose most sales to Airbus if the aircraft were compared on their merits so they were banking hard on their huge pool of certified pilots as the competitive edge. If you listen to podcasts, these two episodes of Causality are excellent: https://engineered.network/causality/episode-33-737-max/ https://engineered.network/causality/episode-33-737-max/ https://engineered.network/causality/episode-50-737-max-ethiopian-air/ https://engineered.network/causality/episode-50-737-max-ethi...
  - bb88 3y ago
    You might enjoy this. I have a pin that blinks "AOA Disagree". Back when I flew regularly before covid, I was tempted to create a bunch of these and hand them out to the flight crew for the flights I flew on.
    - acdha 3y ago
      Ha, playing hardball! I wonder whether you’d find pilots who are Boeing loyalists who’d take offense, or if those guys are even madder at the current management for letting them down.
disillusioned 3y ago
Even more ridiculous, Boeing offered a second source of truth option, but marked it as an upcharge, which the airlines in question rejected. "No thanks, no need for a second AoA sensor, one is none is probably fine!"
- bshacklett 3y ago
  Additionally, two feels like a really strange number. I would think three for a tiebreaker would be standard for any sensor with that much impact (no pun intended).
  - ShadowBanThis01 3y ago
    Yes, two would be very ill-advised. I think there was some incident where a plane had only two pitot tubes and of course this caused problems. Or... I may have simply misremembered pitot tubes instead of AOA sensors in the Boeing case.
SoftTalker 3y ago
Pilots should (are supposed to) disable the auto-trim if it's doing something uncommanded/unexpected. Runaway trim can happen for reasons other than faulty software. MCAS was a new factor and they should have been told about it, I don't dispute that at all.
- deleted 3y ago
  [deleted]
- drtgh 3y ago
  The manufacturer company put in larger engines than the aircraft is designed for. And they did it to avoid all the homologation licences and design costs involved in bringing a new aircraft to market with the appropriate tolerances, and to compete with another company's aircraft in time (Loss of sales). They introduced MCAS in the aircraft for to balance by software a hardware issue, a big design negligent issue which can lead to stalling. It is beyond to trim an aircraft, and because of this there is a big difference in the scale of the values that the algorithm manages from a trimming. It is not my field, but I think it is not a simple factor, and that it should not be put this over the Pilots like if it were a normal aircraft that received a simple update. Every pilot flying that plane should have been warned that it was not a classic plane with a classic update. If this type of behaviour by aircraft manufacturers becomes the norm, costs over safety, we as passengers will suffer it, as other passengers unfortunately suffered it, while they blame the Pilots. In addition that nowadays the China's aircraft manufacturing industry wants to enter global market. Some days ago I read they want permission (homologations approvals) for to enter in the European Union. PS: They also cut costs retiring backup sensors, delegating responsibility for a vital system due the MCAS to the buyer as if it was an unimportant feature; disaster was the order of the day. And the spending cuts were not limited to that, as we have seen in recent days.
  - drtgh 3y ago
    Where I wrote, > They introduced MCAS in the aircraft for to balance by software a hardware issue, a big design negligent issue which can lead to stalling. > Every pilot flying that plane should have been warned that it was not a classic plane with a classic update. I was mean, > They introduced MCAS to use software to attempt to balance an aerodynamically unbalanced aircraft with a high stall tendency, in order to avoid designing a new aircraft. > Any pilot flying that aircraft should have been warned that it was a plane that didn't want to fly aerodynamically, with software forcing it to fly without backed redundancy. It was not mere trimming.

ethbr1 3y ago

Pilots are definitely trained how to disable the autopilot, if needed. Afaic, the fault apportionment was Boeing documentation > airlines >> pilots > Boeing technical design.

diabeetusman 3y ago
Not sure why you’re bringing up autopilot— the MCAS system runs even when the autopilot is disabled. Edit: Also, how does the fault lie with the airlines? Boeing didn’t document the existence of MCAS in the flight manual or training materials.
- ethbr1 3y ago
  Because the comment I was replying to >> Because the pilots should have been trained to unplug the computer to stop it from crashing the plane? Yes. The fault lies with the airlines because I don't for a second believe they didn't put pressure on Boeing to get the MAX certified without mandating retraining. And then once that was done, didn't dig into the details too hard about what changes were made. I have a low tolerance for 'I set up all the conditions and incentives to encourage you to break the law... but you should take all the blame when it explodes.' At some point, the customer has to take some responsibility for what they asked for.
  - actionfromafar 3y ago
    It’s easier to blame Boeing because they made the damn thing its documentation. We know for a fact they are at fault. Some or all of the airlines may or may not have put pressure on Boeing.
- numpad0 3y ago
  Wasn't MCAS designed to activate when A/P is disconnected, also?
acdha 3y ago
This wasn’t related to autopilot and they removed mention of the MCAS system from the documentation to support the main selling point of the 737 MAX, which was that existing 737 pilots would be able to switch easily without recertification. They knew that they’d lose most sales to Airbus if the aircraft were compared on their merits so they were banking hard on their huge pool of certified pilots as the competitive edge. If you listen to podcasts, these two episodes of Causality are excellent: https://engineered.network/causality/episode-33-737-max/ https://engineered.network/causality/episode-33-737-max/ https://engineered.network/causality/episode-50-737-max-ethiopian-air/ https://engineered.network/causality/episode-50-737-max-ethi...
- bb88 3y ago
  You might enjoy this. I have a pin that blinks "AOA Disagree". Back when I flew regularly before covid, I was tempted to create a bunch of these and hand them out to the flight crew for the flights I flew on.
  - acdha 3y ago
    Ha, playing hardball! I wonder whether you’d find pilots who are Boeing loyalists who’d take offense, or if those guys are even madder at the current management for letting them down.

disillusioned 3y ago

Even more ridiculous, Boeing offered a second source of truth option, but marked it as an upcharge, which the airlines in question rejected. "No thanks, no need for a second AoA sensor, one is none is probably fine!"

bshacklett 3y ago
Additionally, two feels like a really strange number. I would think three for a tiebreaker would be standard for any sensor with that much impact (no pun intended).
- ShadowBanThis01 3y ago
  Yes, two would be very ill-advised. I think there was some incident where a plane had only two pitot tubes and of course this caused problems. Or... I may have simply misremembered pitot tubes instead of AOA sensors in the Boeing case.

SoftTalker 3y ago

Pilots should (are supposed to) disable the auto-trim if it's doing something uncommanded/unexpected. Runaway trim can happen for reasons other than faulty software. MCAS was a new factor and they should have been told about it, I don't dispute that at all.

deleted 3y ago
[deleted]
drtgh 3y ago
The manufacturer company put in larger engines than the aircraft is designed for. And they did it to avoid all the homologation licences and design costs involved in bringing a new aircraft to market with the appropriate tolerances, and to compete with another company's aircraft in time (Loss of sales). They introduced MCAS in the aircraft for to balance by software a hardware issue, a big design negligent issue which can lead to stalling. It is beyond to trim an aircraft, and because of this there is a big difference in the scale of the values that the algorithm manages from a trimming. It is not my field, but I think it is not a simple factor, and that it should not be put this over the Pilots like if it were a normal aircraft that received a simple update. Every pilot flying that plane should have been warned that it was not a classic plane with a classic update. If this type of behaviour by aircraft manufacturers becomes the norm, costs over safety, we as passengers will suffer it, as other passengers unfortunately suffered it, while they blame the Pilots. In addition that nowadays the China's aircraft manufacturing industry wants to enter global market. Some days ago I read they want permission (homologations approvals) for to enter in the European Union. PS: They also cut costs retiring backup sensors, delegating responsibility for a vital system due the MCAS to the buyer as if it was an unimportant feature; disaster was the order of the day. And the spending cuts were not limited to that, as we have seen in recent days.
- drtgh 3y ago
  Where I wrote, > They introduced MCAS in the aircraft for to balance by software a hardware issue, a big design negligent issue which can lead to stalling. > Every pilot flying that plane should have been warned that it was not a classic plane with a classic update. I was mean, > They introduced MCAS to use software to attempt to balance an aerodynamically unbalanced aircraft with a high stall tendency, in order to avoid designing a new aircraft. > Any pilot flying that aircraft should have been warned that it was a plane that didn't want to fly aerodynamically, with software forcing it to fly without backed redundancy. It was not mere trimming.