6 ms·

If pilots and pilot unions are satisfied with the results, I'm satisfied with the results. There's no-one more safety conscious in the aviation industry than pi

If pilots and pilot unions are satisfied with the results, I'm satisfied with the results. There's no-one more safety conscious in the aviation industry than pilots, since they're responsible for the souls on board their aircraft, including their own.

r00fus 7y ago
They should be forced to add the 3-sensor config on the plane and have that supported by the MCAS for all planes. A single sensor failing and causing unlimited automatic shifts in pitch is a nightmare I will not fly on.
- qaq 7y ago
  It's no longer unlimited
  - hetspookjee 7y ago
    Well, that's a relief.
    - platz 7y ago
      So if that software fix relieves you, wouldnt you have to admit that it was the software the was the most direct reason for the crashes? HN folks here seem hesitant to say this. But without the dumb ability to do repeated activations it would've been a much less severe problem.
      - hu3 7y ago
        The software did exactly what it was told to do. The error was in the specification.
        platz 7y ago
        Hah, wow
        thombat 7y ago
        Let's suppose that the entire control logic for MCAS was now re-implemented with vacuum tubes. Would you now argue that the aircraft crashes indicate a hardware problem? Or would you agree that the real problem is in the system design, since any conforming implementation of it will produce the jeopardy?
        platz 7y ago
        If it was implemented with vacuum tubes, that would indicate a hardware problem as well as a system design problem. So in this situation, the claim is that braindead contractors mechanically implemented something to spec by force of law? Sure, then whoever designed the logic is accountable. In 99.9% other environments, the distinction is collapsed because the implementor typically has responsibility to design sub-component level logic correctly, to high-level requirements, but also to overall business need and in service to even higher level project goals, and the team that designed the logic is also implemented by the same team.
        bdavis__ 7y ago
        nope, all of the vacum tubes would be working as designed. not a hardware problem, a system design problem. thus the invention of a discipline called 'systems engineering'.. i would say in 100% of engineering development, the design is done as a system, and specific requirements are allocated to design elements (like MCAS software). Each of these elements is tested against the requirements. aeronautical engineering is a very specific skill. so is aircraft controls. so is airworthiness. a software engineer is an expert in software, not these other disciplines.
        platz 7y ago
        At the level of specification you've laid out here, the act of 'software development' is reduced to almost nothing, and you have re-categorized the entire effort as systems engineering.
  - comex 7y ago
    And it’s now 2-sensor.
- cameldrv 7y ago
  The fix means MCAS doesn't activate unless two sensors roughly agree, and it only activates once, which means that the plane is still controllable with just the yoke after MCAS activation. MCAS will also deactivate if the yoke is pulled back (questionable IMO, since it is supposed to compensate for mishandling), and you can leave the electric trim on and undo what MCAS did without fear of it activating again. IMO the risk of a mistaken activation that leads to an accident is extremely remote with these changes.
  - peteradio 7y ago
    I thought the MCAS would typically be activated while the pilot would already be pulling pack on the yoke. So I'm a little confused under what circumstances MCAS would ever activate. Does it activate while yoke is pulled back but the pilot can additionally yank harder to deactivate?
    - cameldrv 7y ago
      Yes, it typically would. There's something called an aft column cutout switch which deactivates nose down trim if you're pulling back on the yoke with a certain amount of force. They're proposing to use this switch to deactivate MCAS. I'm unsure how much force it takes to activate this switch, but it seems to me that this makes MCAS less useful for its intended purpose, and that's why I said this decision was questionable.
- phire 7y ago
  The new software has been updated to use both sensors. It won't activate when sensors disagree by more than 5.5 degrees. The new software now only does a single stabilizer movement. They have eliminated all known failure conditions which might cause multiple movements. With only a single movement, the pilots will be able to counteract the force. Two sensors is not quite as good as three sensors. It can't know which sensor is bad. But it can disable itself and prevent unintended activations. The new software, when combined with adequate pilot simulator training to both disable MCAS when it encounters an issue, and to fly the plane in with MCAS disabled makes things safe enough.
  - vkou 7y ago
    So, this fixes the MCAS problem (Where the plane plunges nose-first into the ground, despite the best attempt by the pilots to pull the stick up)... But how does this fix the problem that MCAS was supposed to be a band-aid over (That the plane is aerodynamically unstable during take-off, and pulling too much on the stick will cause the plane to easily stall)..? The new MCAS sounds like it will only protect against this instability once - and, if overriden, will not do anything to protect against a stall?
    - tzs 7y ago
      > But how does this fix the problem that MCAS was supposed to be a band-aid over (That the plane is aerodynamically unstable during take-off, and pulling too much on the stick will cause the plane to easily stall)..? MCAS is not even enabled during take-off, which makes it hard to see how it could be meant to address supposed stability problems during take-off. It can't come on until the flaps are retracted.
    - sokoloff 7y ago
      The 737-Max is not “aerodynamically unstable”. (It does not exhibit negative longitudinal stability.)
    - phire 7y ago
      I mean, that's true of every plane. You pull back too much, it will stall. It's not that the MAX stalls super easily, It's not an instability. It's just that the controls feel wrong when approaching stall. The FAA have pretty precise regulations about how much backpressure the pilots should feel when approaching stall. In normal flight, the plane is never anywhere near stalling, so MCAS never activates. Nor do the pilots encounter this weird stall. The combined chances of both MCAS being disabled AND the pilot not recognizing the stall is pretty low. But this is why the simulator training is important, so the pilots are familiar with the new feel as the plane approaches stall.
- o-__-o 7y ago
  couldn't make it 3 sensor that would change the certification (obviously they can now) but I wonder what this means for Southwest Air. The whole reason the MAX exists is because of Southwest. If southwest didn't throw their weight around and loudly announce they were considering Airbus, the MAX would likely exist in a non-737 configuration right now.
  - r00fus 7y ago
    > If southwest didn't throw their weight around So wait, it's a customer's fault that the supplier cheated the regulations?
    - redis_mlc 7y ago
      Yes, Boeing agreed to pay Southwest $1 million per airplane if retraining was required.
      - o-__-o 7y ago
        And now retraining is required and we still have the MAX abomination. It’s not a bad plane, I’d happily fly on it again.. it’s just a dumb fuselage for modernizing a fleet
mrtksn 7y ago
Their jobs are on the line too which complicates things. I don't recall many pilots expressing distrust towards Boineng and FAA, the narrative always was "Don't worry, the issue is handled by professionals, these planes are safe". The planes turned out not to be safe.
- pfundstein 7y ago
  The pilots weren't aware of the issue, or how to disable MCAS.
  - mrtksn 7y ago
    So their claims of safety were not well informed? I think the problem is that they trust a system that got corrupted or never was that robust in the first place. Seeing how this thing unfolded, I don't really believe that people making claims are in good authority to make those claims.
    - netsharc 7y ago
      Well, now that it's all blown up, the pilots should know not to trust the system, and challenge it. And I would delegate my skepticism to them and trust their judgement. Because if the plane crashes, it's not just their occupation in the line, it's their lives.
      - mrtksn 7y ago
        Any information about the inspections and studies conducted by those pilots who make the claims? They probably "should" learnt a thing or two from this but did they?
      - frenchyatwork 7y ago
        > Well, now that it's all blown up, the pilots should know not to trust the system, and challenge it. That they should in no way proves that they do. Computer programmers build all sorts of foot-guns with the idea that they'll be clever enough to avoid them in the future. I expect pilots are a little more humble and self-aware than that, but they're still human.
freepor 7y ago
But pilots are subject to Dunning Kruger. Most probably think they could figure out how to handle MCAS and give the OK but in reality it might be over optimistic.
deleted 7y ago
[deleted]

r00fus 7y ago

They should be forced to add the 3-sensor config on the plane and have that supported by the MCAS for all planes. A single sensor failing and causing unlimited automatic shifts in pitch is a nightmare I will not fly on.

qaq 7y ago
It's no longer unlimited
- hetspookjee 7y ago
  Well, that's a relief.
  - platz 7y ago
    So if that software fix relieves you, wouldnt you have to admit that it was the software the was the most direct reason for the crashes? HN folks here seem hesitant to say this. But without the dumb ability to do repeated activations it would've been a much less severe problem.
    - hu3 7y ago
      The software did exactly what it was told to do. The error was in the specification.
      - platz 7y ago
        Hah, wow
        thombat 7y ago
        Let's suppose that the entire control logic for MCAS was now re-implemented with vacuum tubes. Would you now argue that the aircraft crashes indicate a hardware problem? Or would you agree that the real problem is in the system design, since any conforming implementation of it will produce the jeopardy?
        platz 7y ago
        If it was implemented with vacuum tubes, that would indicate a hardware problem as well as a system design problem. So in this situation, the claim is that braindead contractors mechanically implemented something to spec by force of law? Sure, then whoever designed the logic is accountable. In 99.9% other environments, the distinction is collapsed because the implementor typically has responsibility to design sub-component level logic correctly, to high-level requirements, but also to overall business need and in service to even higher level project goals, and the team that designed the logic is also implemented by the same team.
        bdavis__ 7y ago
        nope, all of the vacum tubes would be working as designed. not a hardware problem, a system design problem. thus the invention of a discipline called 'systems engineering'.. i would say in 100% of engineering development, the design is done as a system, and specific requirements are allocated to design elements (like MCAS software). Each of these elements is tested against the requirements. aeronautical engineering is a very specific skill. so is aircraft controls. so is airworthiness. a software engineer is an expert in software, not these other disciplines.
        platz 7y ago
        At the level of specification you've laid out here, the act of 'software development' is reduced to almost nothing, and you have re-categorized the entire effort as systems engineering.
- comex 7y ago
  And it’s now 2-sensor.
cameldrv 7y ago
The fix means MCAS doesn't activate unless two sensors roughly agree, and it only activates once, which means that the plane is still controllable with just the yoke after MCAS activation. MCAS will also deactivate if the yoke is pulled back (questionable IMO, since it is supposed to compensate for mishandling), and you can leave the electric trim on and undo what MCAS did without fear of it activating again. IMO the risk of a mistaken activation that leads to an accident is extremely remote with these changes.
- peteradio 7y ago
  I thought the MCAS would typically be activated while the pilot would already be pulling pack on the yoke. So I'm a little confused under what circumstances MCAS would ever activate. Does it activate while yoke is pulled back but the pilot can additionally yank harder to deactivate?
  - cameldrv 7y ago
    Yes, it typically would. There's something called an aft column cutout switch which deactivates nose down trim if you're pulling back on the yoke with a certain amount of force. They're proposing to use this switch to deactivate MCAS. I'm unsure how much force it takes to activate this switch, but it seems to me that this makes MCAS less useful for its intended purpose, and that's why I said this decision was questionable.
phire 7y ago
The new software has been updated to use both sensors. It won't activate when sensors disagree by more than 5.5 degrees. The new software now only does a single stabilizer movement. They have eliminated all known failure conditions which might cause multiple movements. With only a single movement, the pilots will be able to counteract the force. Two sensors is not quite as good as three sensors. It can't know which sensor is bad. But it can disable itself and prevent unintended activations. The new software, when combined with adequate pilot simulator training to both disable MCAS when it encounters an issue, and to fly the plane in with MCAS disabled makes things safe enough.
- vkou 7y ago
  So, this fixes the MCAS problem (Where the plane plunges nose-first into the ground, despite the best attempt by the pilots to pull the stick up)... But how does this fix the problem that MCAS was supposed to be a band-aid over (That the plane is aerodynamically unstable during take-off, and pulling too much on the stick will cause the plane to easily stall)..? The new MCAS sounds like it will only protect against this instability once - and, if overriden, will not do anything to protect against a stall?
  - tzs 7y ago
    > But how does this fix the problem that MCAS was supposed to be a band-aid over (That the plane is aerodynamically unstable during take-off, and pulling too much on the stick will cause the plane to easily stall)..? MCAS is not even enabled during take-off, which makes it hard to see how it could be meant to address supposed stability problems during take-off. It can't come on until the flaps are retracted.
  - sokoloff 7y ago
    The 737-Max is not “aerodynamically unstable”. (It does not exhibit negative longitudinal stability.)
  - phire 7y ago
    I mean, that's true of every plane. You pull back too much, it will stall. It's not that the MAX stalls super easily, It's not an instability. It's just that the controls feel wrong when approaching stall. The FAA have pretty precise regulations about how much backpressure the pilots should feel when approaching stall. In normal flight, the plane is never anywhere near stalling, so MCAS never activates. Nor do the pilots encounter this weird stall. The combined chances of both MCAS being disabled AND the pilot not recognizing the stall is pretty low. But this is why the simulator training is important, so the pilots are familiar with the new feel as the plane approaches stall.
o-__-o 7y ago
couldn't make it 3 sensor that would change the certification (obviously they can now) but I wonder what this means for Southwest Air. The whole reason the MAX exists is because of Southwest. If southwest didn't throw their weight around and loudly announce they were considering Airbus, the MAX would likely exist in a non-737 configuration right now.
- r00fus 7y ago
  > If southwest didn't throw their weight around So wait, it's a customer's fault that the supplier cheated the regulations?
  - redis_mlc 7y ago
    Yes, Boeing agreed to pay Southwest $1 million per airplane if retraining was required.
    - o-__-o 7y ago
      And now retraining is required and we still have the MAX abomination. It’s not a bad plane, I’d happily fly on it again.. it’s just a dumb fuselage for modernizing a fleet

mrtksn 7y ago

Their jobs are on the line too which complicates things. I don't recall many pilots expressing distrust towards Boineng and FAA, the narrative always was "Don't worry, the issue is handled by professionals, these planes are safe". The planes turned out not to be safe.

pfundstein 7y ago
The pilots weren't aware of the issue, or how to disable MCAS.
- mrtksn 7y ago
  So their claims of safety were not well informed? I think the problem is that they trust a system that got corrupted or never was that robust in the first place. Seeing how this thing unfolded, I don't really believe that people making claims are in good authority to make those claims.
  - netsharc 7y ago
    Well, now that it's all blown up, the pilots should know not to trust the system, and challenge it. And I would delegate my skepticism to them and trust their judgement. Because if the plane crashes, it's not just their occupation in the line, it's their lives.
    - mrtksn 7y ago
      Any information about the inspections and studies conducted by those pilots who make the claims? They probably "should" learnt a thing or two from this but did they?
    - frenchyatwork 7y ago
      > Well, now that it's all blown up, the pilots should know not to trust the system, and challenge it. That they should in no way proves that they do. Computer programmers build all sorts of foot-guns with the idea that they'll be clever enough to avoid them in the future. I expect pilots are a little more humble and self-aware than that, but they're still human.

freepor 7y ago

But pilots are subject to Dunning Kruger. Most probably think they could figure out how to handle MCAS and give the OK but in reality it might be over optimistic.

deleted 7y ago

[deleted]