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> probably know more about the flaws in the MAX The thing is, we do know a lot about those flaws and the only way to really fix those flaws is with a clean-she

> probably know more about the flaws in the MAX The thing is, we do know a lot about those flaws and the only way to really fix those flaws is with a clean-sheet redesign. The MAX would have flown again, for sure, pre-COVID. However, designs without known fundamental design flaws can handle worldwide airline lift needs for the foreseeable future.. and it's legitimate to wonder what that means for the future of the MAX.

hn_throwaway_99 6y ago
> The thing is, we do know a lot about those flaws and the only way to really fix those flaws is with a clean-sheet redesign. That's just not true. People seem to be conflating the fact that the design required software-controlled stability (e.g. MCAS) as a "fundamental" design issue. That's just not the case. The problems were: 1. MCAS was not sufficiently redundant. 2. Boeing tried to get away with the changes to the MAX without requiring recertification or pilot retraining, which was just wrong. Both #1 and #2 have straightforward fixes.
- GekkePrutser 6y ago
  Yes, I'm kinda surprised they didn't use the COVID lockdown period to do proper pilot training. Most pilots and planes were basically sitting idle anyway. It's good for them to remain somewhat active. And fuel was given away for pretty much free because the overproduction was filling up expensive storage space. This would have been the ideal moment to teach 737 pilots to properly handle the Max aircraft without needing MCAS.
  - kayfox 6y ago
    > This would have been the ideal moment to teach 737 pilots to properly handle the Max aircraft without needing MCAS. Well, its not legal to have the 737 MAX without MCAS, so its a moot point. MCAS exists to compensate for undesired control forces as high (near-stall) angles of attack, its not legal to have those performance characteristics in an aircraft. If this was Airbus, this would have been done in software since the A320 series is fly by wire.
- SAI_Peregrinus 6y ago
  #1 requires fitting another AOA sensor vane. This is not being done. It would void the existing type certification, at which point the reason to avoid a clean-sheet redesign is gone. If they could have designed a new aircraft around the more efficient engines at the same size and have airlines buy it they would have. But without a 737 type certificate Southwest (their largest single customer for 737s, Southwest only flys 737s) won't buy and many others will be more reluctant to buy. #2 is being changed.
  - hn_throwaway_99 6y ago
    > #1 requires fitting another AOA sensor vane This is baloney. There are already 2 AOA sensors on the plane, but MCAS originally only read from one of them: https://arstechnica.com/information-technology/2019/03/boeing-sold-safety-feature-that-could-have-prevented-737-max-crashes-as-an-option/ https://arstechnica.com/information-technology/2019/03/boein...
    - SAI_Peregrinus 6y ago
      There need to be at least 3. With two a disagreement cannot be resolved by majority, so the new MCAS will have to disable itself. Pilots will need to be trained to handle this failure mode, and the indicators will need to be added to all the planes (and will need to work, that was an additional issue). This is a fundamental design flaw for a system which can have catastrophic consequences. This should have been classified as a DO-178B level A system (capable of crashing the plane) but was misclassified by Boeing. DO-178B level A systems require triple redundancy.

hn_throwaway_99 6y ago

> The thing is, we do know a lot about those flaws and the only way to really fix those flaws is with a clean-sheet redesign. That's just not true. People seem to be conflating the fact that the design required software-controlled stability (e.g. MCAS) as a "fundamental" design issue. That's just not the case. The problems were: 1. MCAS was not sufficiently redundant. 2. Boeing tried to get away with the changes to the MAX without requiring recertification or pilot retraining, which was just wrong. Both #1 and #2 have straightforward fixes.

GekkePrutser 6y ago
Yes, I'm kinda surprised they didn't use the COVID lockdown period to do proper pilot training. Most pilots and planes were basically sitting idle anyway. It's good for them to remain somewhat active. And fuel was given away for pretty much free because the overproduction was filling up expensive storage space. This would have been the ideal moment to teach 737 pilots to properly handle the Max aircraft without needing MCAS.
- kayfox 6y ago
  > This would have been the ideal moment to teach 737 pilots to properly handle the Max aircraft without needing MCAS. Well, its not legal to have the 737 MAX without MCAS, so its a moot point. MCAS exists to compensate for undesired control forces as high (near-stall) angles of attack, its not legal to have those performance characteristics in an aircraft. If this was Airbus, this would have been done in software since the A320 series is fly by wire.
SAI_Peregrinus 6y ago
#1 requires fitting another AOA sensor vane. This is not being done. It would void the existing type certification, at which point the reason to avoid a clean-sheet redesign is gone. If they could have designed a new aircraft around the more efficient engines at the same size and have airlines buy it they would have. But without a 737 type certificate Southwest (their largest single customer for 737s, Southwest only flys 737s) won't buy and many others will be more reluctant to buy. #2 is being changed.
- hn_throwaway_99 6y ago
  > #1 requires fitting another AOA sensor vane This is baloney. There are already 2 AOA sensors on the plane, but MCAS originally only read from one of them: https://arstechnica.com/information-technology/2019/03/boeing-sold-safety-feature-that-could-have-prevented-737-max-crashes-as-an-option/ https://arstechnica.com/information-technology/2019/03/boein...
  - SAI_Peregrinus 6y ago
    There need to be at least 3. With two a disagreement cannot be resolved by majority, so the new MCAS will have to disable itself. Pilots will need to be trained to handle this failure mode, and the indicators will need to be added to all the planes (and will need to work, that was an additional issue). This is a fundamental design flaw for a system which can have catastrophic consequences. This should have been classified as a DO-178B level A system (capable of crashing the plane) but was misclassified by Boeing. DO-178B level A systems require triple redundancy.