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>, “Boeing 737-800 pilots were required to receive some additional training on the MAX 8, which included an hour lesson on some differences. Additional training

>, “Boeing 737-800 pilots were required to receive some additional training on the MAX 8, which included an hour lesson on some differences. Additional training was not required, as the 737-800 and the MAX 8 have same type certification.” How are those type certifications determined? It seems to me that there should be an instance checking if the type certifications make sense. Or perhaps they did, and they just really look like similar planes. In which case I wonder if the threshold for 'versioning' should be changed. (I know nothing of how this actually works, it just baffles me that seemingly different planes get the same certificate) EDIT: I read the FAA does check this, but I wonder on what _grounds_ it makes the decisions.

mcv 8y ago
It makes sense that very minor differences don't require extra training if the differences have no meaningful impact on cockpit design or flight characteristics. But in this case, flight characteristics were clearly different, and MCAS was supposed to compensate for those differences. I don't know how they measure such differences, but you'd think that different engines, different aerodynamics, and a new control system to compensate for those differences, are enough to warrant a new type certification.
- rob74 8y ago
  well, yes, exactly, MCAS was supposed to compensate for these differences, to make sure that the flight characteristics are close enough to not require additional training. But tragically, what was supposed to be part of the solution turned out to be part of the problem...
- yason 8y ago
  They should really have type certification diffs. If 90% of the airplane is the same as the previous version, the manufacturer should expect a type certification procedure that costs about 10% of a fully new design and pilots should gain the new type rating with about 10% of the effort and hours of what would be required for a completely new plane. It sounds really cumbersome to have it either-or way, making it difficult to develop planes too much incrementally and keeping it very costly to start from scratch with a completely new design.
saluki 8y ago
y, sounds like a change like this: The system, known as the Maneuvering Characteristics Augmentation System, or MCAS, was incorporated because the plane has larger engines placed further forward on the craft, and so has a chance of facing a stall at lower speeds than earlier 737 variations. Would require more training than a few hours.
- deleted 8y ago
  [deleted]
- VBprogrammer 8y ago
  Do you have a citation for "incorporated because the plane...has a chance of facing a stall at lower speeds than earlier 737 variations". I think you may have misread something. Normally stalling at a lower speed is a good thing.
  - resoluteteeth 8y ago
    I don't think the comment you are responding to means "the speeds at which it will stall are lower compared to earlier 737 variations," but rather "at low speeds, it has a greater chance of stalling compared to earlier 737 variations."
    - pdonis 8y ago
      It doesn't matter which of those two the poster meant; they're both wrong as descriptions of the effect of the new engines on the 737 MAX. See my other post upthread.
- pdonis 8y ago
  > has a chance of facing a stall at lower speeds than earlier 737 variations No, that's not the issue. The issue is that, because of the pitch up moment created by the engines, at higher angles of attack the force required to move the yoke decreases instead of increasing. That's (a) a highly undesirable characteristic since the changing feedback confuses pilots and makes it hard for them to know when a stall is imminent, and (b) a violation of FAA certification requirements. MCAS was added to compensate for the pitch up moment from the engines by adding nose down trim, so the yoke force would be similar to that of previous 737 models.
ams6110 8y ago
More and more of this has been delegated to the manufacturers themselves. They simply assert to the FAA that the aircraft meets the type requirements. Boeing showed the FAA their test results, said that with MCAS the aircraft meets requirements, doesn't require extra training, and the FAA took their word for it. Authorities in most other countries trust the FAA, so they took their word for it too. That's an oversimplification, but more or less what happened. As to whether Boeing was deliberately deceptive, we'll probably find out in due time as investigations have begun and subpoenas issued.
- stcredzero 8y ago
  More and more of this has been delegated to the manufacturers themselves. They simply assert to the FAA that the aircraft meets the type requirements. To assert this, but also change such a critical emergency procedure, which is made more critical by a decision motivated primarily by economics -- this just sounds bad. Basically, we've set up a situation where short term thinking is eventually, over many thousands of iterations of such decisions which go into producing such a complex product, going to override long term safety thinking. Unfortunately, substituting regulations for good thinking has the potential to nonsensically stymie progress if done incorrectly.
  - sundaeofshock 8y ago
    “Unfortunately, substituting regulations for good thinking has the potential to nonsensically stymie progress if done incorrectly.” Help me understand this statement. Are you suggesting that regulation in this instance would not help with safety?
    - stcredzero 8y ago
      Are you suggesting that regulation in this instance would not help with safety? Not at all. Often regulations help with safety in the short and medium term. The problem is that they aren't written by oracles, so they can become outdated and fail to account for changes in technology. (How does "stymie progress" translate to not helping with safety?)

mcv 8y ago

It makes sense that very minor differences don't require extra training if the differences have no meaningful impact on cockpit design or flight characteristics. But in this case, flight characteristics were clearly different, and MCAS was supposed to compensate for those differences. I don't know how they measure such differences, but you'd think that different engines, different aerodynamics, and a new control system to compensate for those differences, are enough to warrant a new type certification.

rob74 8y ago
well, yes, exactly, MCAS was supposed to compensate for these differences, to make sure that the flight characteristics are close enough to not require additional training. But tragically, what was supposed to be part of the solution turned out to be part of the problem...
yason 8y ago
They should really have type certification diffs. If 90% of the airplane is the same as the previous version, the manufacturer should expect a type certification procedure that costs about 10% of a fully new design and pilots should gain the new type rating with about 10% of the effort and hours of what would be required for a completely new plane. It sounds really cumbersome to have it either-or way, making it difficult to develop planes too much incrementally and keeping it very costly to start from scratch with a completely new design.

saluki 8y ago

y, sounds like a change like this: The system, known as the Maneuvering Characteristics Augmentation System, or MCAS, was incorporated because the plane has larger engines placed further forward on the craft, and so has a chance of facing a stall at lower speeds than earlier 737 variations. Would require more training than a few hours.

deleted 8y ago
[deleted]
VBprogrammer 8y ago
Do you have a citation for "incorporated because the plane...has a chance of facing a stall at lower speeds than earlier 737 variations". I think you may have misread something. Normally stalling at a lower speed is a good thing.
- resoluteteeth 8y ago
  I don't think the comment you are responding to means "the speeds at which it will stall are lower compared to earlier 737 variations," but rather "at low speeds, it has a greater chance of stalling compared to earlier 737 variations."
  - pdonis 8y ago
    It doesn't matter which of those two the poster meant; they're both wrong as descriptions of the effect of the new engines on the 737 MAX. See my other post upthread.
pdonis 8y ago
> has a chance of facing a stall at lower speeds than earlier 737 variations No, that's not the issue. The issue is that, because of the pitch up moment created by the engines, at higher angles of attack the force required to move the yoke decreases instead of increasing. That's (a) a highly undesirable characteristic since the changing feedback confuses pilots and makes it hard for them to know when a stall is imminent, and (b) a violation of FAA certification requirements. MCAS was added to compensate for the pitch up moment from the engines by adding nose down trim, so the yoke force would be similar to that of previous 737 models.

ams6110 8y ago

More and more of this has been delegated to the manufacturers themselves. They simply assert to the FAA that the aircraft meets the type requirements. Boeing showed the FAA their test results, said that with MCAS the aircraft meets requirements, doesn't require extra training, and the FAA took their word for it. Authorities in most other countries trust the FAA, so they took their word for it too. That's an oversimplification, but more or less what happened. As to whether Boeing was deliberately deceptive, we'll probably find out in due time as investigations have begun and subpoenas issued.

stcredzero 8y ago
More and more of this has been delegated to the manufacturers themselves. They simply assert to the FAA that the aircraft meets the type requirements. To assert this, but also change such a critical emergency procedure, which is made more critical by a decision motivated primarily by economics -- this just sounds bad. Basically, we've set up a situation where short term thinking is eventually, over many thousands of iterations of such decisions which go into producing such a complex product, going to override long term safety thinking. Unfortunately, substituting regulations for good thinking has the potential to nonsensically stymie progress if done incorrectly.
- sundaeofshock 8y ago
  “Unfortunately, substituting regulations for good thinking has the potential to nonsensically stymie progress if done incorrectly.” Help me understand this statement. Are you suggesting that regulation in this instance would not help with safety?
  - stcredzero 8y ago
    Are you suggesting that regulation in this instance would not help with safety? Not at all. Often regulations help with safety in the short and medium term. The problem is that they aren't written by oracles, so they can become outdated and fail to account for changes in technology. (How does "stymie progress" translate to not helping with safety?)