12 ms·

Keep talking about the software. Make it about the software, so no one knows the airframe is fundamentally flawed..

artsyca 7y ago
A Faustion proposition -- they're going to release software updates from here to the apocalypse yet none of them will succeed in winning back anybody's trust; they should implement a code freeze until hell freezes over
rrss 7y ago
How do you know the airframe is fundamentally flawed? ("the engines are too big" is not an answer).
- dboreham 7y ago
  The wings are too low?
- notjustanymike 7y ago
  Keeps crashing into the ocean
- toomuchtodo 7y ago
  If the airframe isn’t flawed, fly it without MCAS. With Boeing management onboard. Surely you don’t need to dynamically adjust flight dynamics without the pilot’s input or knowledge if the airframe is sound. It’s realistic to build aircraft where software is required to fly said aircraft depending on the flight dynamics, and the pilot(s) are fully aware of what’s running. But that changes the type rating and blows Boeing’s regulatory sidestep out of the sky.
  - TylerE 7y ago
    God it's frustrating seeing people here talk about aviation. Flight computers are a fundamental part of normal aeronautical design. Asking Boeing to fly a Max without MCAS would be like asking you to write a bug free C++ program... with a compiler with no error messages or validation.
    - toomuchtodo 7y ago
      [removed] Other sibling comments are of higher quality.
      - TylerE 7y ago
        Better not ever fly on an Airbus then, either. https://en.wikipedia.org/wiki/Air_France_Flight_296 https://en.wikipedia.org/wiki/Air_France_Flight_296 https://www.telegraph.co.uk/technology/9231855/Air-France-Flight-447-Damn-it-were-going-to-crash.html https://www.telegraph.co.uk/technology/9231855/Air-France-Fl...
    - windexh8er 7y ago
      The MCAS was a workaround implemented as a stopgap, no? How does this fall under the broad category of a flight computer as you've stated? What other airliners have been retrofitted with similar systems? Why doesn't a non-Max 737 need MCAS?
      - ethbro 7y ago
        No. It was a software fix put in place to satisfy a regulatory requirement under specific, known flight conditions. The following planes (among others) all translate flight inputs. Airbus A320, A330, A340, A350, A380; Boeing 777. https://en.m.wikipedia.org/wiki/Flight_control_modes https://en.m.wikipedia.org/wiki/Flight_control_modes A non-Max 737 doesn't need MCAS because it already behaves like a 737. Essentially, most replies on this boil down to people being shocked (shocked!) that computers are currently helping all planes fly. I'm not sure how they thought AEs were getting efficiency gains while physics stayed the same...
        AnthonBerg 7y ago
        The replies do not all boil down to people being shocked that computers help planes fly. That is a willfully distorted charicature. Hundreds of people were killed due to a bad implementation of a deeply irresponsible and insensible approach to make money by skirting flight safety regulation. The bad implementation was in part software, but nobody is confusing that aspect with the whole picture. The 737 MAX does not need MCAS. Nothing needs MCAS. Boeing executives wanted the money that MCAS made them.
- natch 7y ago
  Isn’t the engines being not mountable at a well balanced point a big part of the answer? Which isn’t down to only the size of the engine but also the height of the wings. So yes it’s complicated but the engine is part of the picture. Although not being in the industry, I don’t know, is a strap-on engine added to a design that wasn’t intended to accommodate it technically considered part of the airframe?
  - _ph_ 7y ago
    Basically no jet engine at any airliner are mounted at a point which is well-balanced in all flight situations. At level flight, the 737 MAX is also well balanced. That is just a matter of weight distribution in the machine. The problem appears at high angle of attacks, that means the force vector isn't pointing vertically down as it were only due to gravity. In this situation, the balance of every aircraft which has large engines hanging down from the wings does shift and needs to be compensated for in some way in the control systems.
- djsumdog 7y ago
  Like the hundreds of other comments on here mentioning how the engines were too far forward. The 737 was originally designed to be low to the ground, and rather than raising the jet and placing engines where they are on other similar planes (meaning it could no longer be classified as a 737 and requiring new manuals/training/certification), they moved them forward and adjusted for the new unexpected handling with the MCAS.
  - blackflame7000 7y ago
    Raising the jet requires a wider body for the landing gear to fold up into
    - kayfox 7y ago
      The 757 sits a good 4 feet higher with the same fuselage diameter.
      - 0az 7y ago
        If I remember correctly, the 737 either doesn't have the space for longer landing gear, or there's an issue with the longer landing gear, or both. Citation needed, of course, as this is off of memory.
        kayfox 7y ago
        It was designed lower to be easier to work with ground handling and servicing. This lead to a few different designs of plane-deployed airstairs and made it popular with Alaska Air and other airlines serving small airports. https://en.wikipedia.org/wiki/Boeing_737#Background https://en.wikipedia.org/wiki/Boeing_737#Background
      - blackflame7000 7y ago
        The 757 has a wingspan 30 feet wider than the 737. If you look at a picture of the airplane, you can see that the landing gear is part of the wing. https://qph.fs.quoracdn.net/main-qimg-0f650e809408f3962a1ed01f08a97470 https://qph.fs.quoracdn.net/main-qimg-0f650e809408f3962a1ed0...
- windexh8er 7y ago
  We know because hundreds of people died in the airframe. We know the MCAS was a workaround to an aerodynamics problem. Boeing has admitted this both directly and indirectly. Airframes shouldn't need software fixes to accommodate for a design failure and design failures shouldn't be allowed to fly after killing hundreds of people. How do you argue what they did and are continuing to do is just in this situation?
  - skybrian 7y ago
    Uncrashable airplanes don't exist. The question isn't whether there were crashes (nobody disputes that). It's whether the problem can be fixed so that pilots can fly it safely. Given all the times the plane flew without incident (other than the two crashes), it seems this should be possible?
    - visarga 7y ago
      Yeah, it was perfectly safe except for two crashes. But that's two crashes more than I can tolerate. The problem is now the lack of public trust in their work. They might fix the software, but how to prove they're not lying again?
      - ethbro 7y ago
        The same way you prove Airbus isn't lying?
        callalex 7y ago
        Presumably Airbus is still being watched by a regulator or two. Unlike Boeing which has not been watched as the FAA has clearly been gutted.
        _ph_ 7y ago
        The 737 MAX will be watched by all regulators world-wide. So it will be checked as carefuly, or actually even way more carefully than any competing aircraft.
- tus88 7y ago
  Because MCAS is required, unlike every other aerodynamically stable airplane that came before it.
  - deleted 7y ago
    [deleted]
  - blackflame7000 7y ago
    https://en.m.wikipedia.org/wiki/Qantas_Flight_72 https://en.m.wikipedia.org/wiki/Qantas_Flight_72
    - makomk 7y ago
      Qantas Flight 72 is probably a good demonstration of why using MCAS as a band-aid for the 737 MAX's stability issues is a bad idea. One of the key reasons that fault didn't lead to a crash that killed everyone on board is that Airbus placed much safer limits on the amount of control authority their flight envelope protections had and the altitude at which they could operate.
  - danjayh 7y ago
    Airbus does it too. They have several control laws that are used to provide flight envelope protection. It was the pilot's failure to understand his plane's software that caused AF447 to crash. Essentially he didn't realize that the flight control software had changed modes, that it wasn't providing the normal handling augmentations, and that his inputs were putting the aircraft into a stall, which caused the crash. See: https://en.wikipedia.org/wiki/Air_France_Flight_447 https://en.wikipedia.org/wiki/Air_France_Flight_447 https://aviation.stackexchange.com/questions/62338/why-did-af447-never-return-to-normal-law https://aviation.stackexchange.com/questions/62338/why-did-a...
    - tus88 7y ago
      Build unstable airframes? Not outside of forward canard jet fighters. And that pilot crashed a perfectly fine airliner after he lost situational awareness and then did the one thing you should never do - pull the steering column back in a mad panic until the plane stalls.
- mseidl 7y ago
  The plane was built in the 50s, it was low to the ground. But Boeing wanted to fit bigger/newer/better engines on it, but they wont fit since you can't make the landing gear longer. They had to move the engines higher and much more forward.
mevile 7y ago
I've read that the problem is all the hoops Boeing is trying to jump through to keep the plane rated as a 737, not the airframe.
- azernik 7y ago
  That need to keep it in the 737 rating drove a lot of the airframe design.
windexh8er 7y ago
This. Given the failures, admissions and scrutiny the FAA is now under there should have been no option for Boeing to continue to band aid the airframe. Boeing should have been forced to pull the plane as "737" and recertify it as a new airframe from scratch. But why weren't they? My guess would be because Boeing would have to eat very large losses of dealing with customer lawsuits (bought an airframe that wasn't certified), would lose all future revenue as customers would cancel orders and buy airworthy competitor options, and Boeing would be forced to say they were wrong. Regardless, this still seems like the right path (recertification). It seems the FAA is still being strong armed by Boeing. Why? Put these people in prison. Shut the 737 Max down. Make Boeing face the music. They need to fail to get the point, apparently.
- mrhappyunhappy 7y ago
  I’m guessing doing all the things the right way would put Boeing out of business. US doesn’t want that.
  - LifeLiverTransp 7y ago
    To fail to big.
- joe_the_user 7y ago
  Having designed the plane to be a "drop-in replacement" for a 737 and having failed at that, it seems like there's no path forward, neither more jury rigging nor certification as something else - because to make the thing like 737, they made it not like a contemporary aircraft (paper manuals is the big example). Boeing have essentially painted themselves into a very costly corner. The FAA or congress could do a "certify it just for Boeing" action and the plane might even, maybe be safe then. But how many airline customers would want to fly in it?
- spookware 7y ago
  Agree, using software to disguise poorly engineered design. Thanks guys.
- _ph_ 7y ago
throwaway3627 7y ago
Remember Al Jazeera's 2010 report on critical defective and substandard structural parts from subcontractor Ducommun? The full scope of potential risk is ALL aircraft Boeing has designed, built, reengineered or maintained in the past 30 years. It's unknown what's hidden, poorly-designed, fragile or likely to fail because of lax self-certification up-and-down the full breadth and depth of equipment and subsystems. There's no way to prove a particular new/recently maintained Boeing plane is safe because the whole regulatory system is broken due to regulatory capture stemming from cozy, military-industrial complex corruption. I do hope Ralph Nader sues the pants off Boeing for killing his goddaughter due to their cheapness and shoddy products.
- mobilefriendly 7y ago
  Ralph Nader lost his grandniece.
cameldrv 7y ago
Fundamentally flawed is too strong. The airframe has some undesirable handling characteristics without augmentation. So does every jet airliner —- they all have yaw dampers at least. Aircraft designers have been solving airframe stability problems with mechanical, hydraulic, analog electronic and fly by wire systems since at least the thirties. The problem is that MCAS doesn’t fail safe. In a perfect would they would have clean sheeted the MAX, but there are numerous ways they could have made it safe, they just didn’t do any of them successfully.
- sundvor 7y ago
  The engines are fundamentally unfit for the airframe.
- salawat 7y ago
  Fundamentally flawed is absolutely an accurate moniker. Yaw dampers are workload mitigation devices; not compensatory for design flaws. Dutch roll is inherent to any controllable aircraft. Violation of 25.173 in the form of decreasing stick force response curves on approach to stall is absolutely not the same beast. Design criteria are prescriptive, and I'm not aware of any line of regulation that says an uncertifiable airframe can be made certifiable by the addition of a computer. These handling characteristics are not undesirable, they are uncertifiable according to regulations as written, and intended. Even Airbus meets these minimum design criteria at their minimum automation threshold. Boeing for some daft reason seems to be being written a pass to selectively ignore regulations around Civil Transport Aircraft certification based on some serious levels of sunk-cost fallacy. I don't believe in supporting limp-wristed minimal compliance when it comes to safety critical engineering. Not going the route of designing out the behavior requires the implementation of system after system, after system to compensate, with each link in the chain adding additional risk for failure over and above what doing it right in the first place would have created. Whitewashing wins no one but Boeing anything. Please remember that. We entrust these people to design and manufacture safer, more efficient, machines. Instead of living up to that mission, they jeopardized it in the name of optimizing the revenue/profit generating characteristics of the company. I get the reluctance to throw away a potentially recoverable airframe, but I'm dead against letting anyone whitewash over the fact the plane is more dangerous than it needed to be because someone wanted better numbers on their held stock, and was willing to put a more dangerous product on the market in able to do it.
ulfw 7y ago
That’s because they’re cheap. Software updates are cheap. Hardware updates are a problem.
kuzehanka 7y ago
Maybe HN needs a way to flag comments as factually inaccurate. This meme about the airframe being 'fundamentally flawed' or 'engines are too big(????)' or inherently unstable has been disproved by everyone in the industry including people invested in Airbus. Please stop perpetuating evening time TV show fearmongering bullshit. The eli5 explanation of the MAX 8 MCAS incident is as follows: * Boeing wanted MAX 8 to have the 737 type rating. This means it must handle and fly just like other 737. This would allow existing 737 pilots to fly the MAX 8 with no additional training. This was part of Boeing's financial advantage. * To achieve the efficiency it has, the MAX 8 has pretty large engines. Because they wanted to keep the airframe like other 737, they couldn't lift the wings to accommodate. Instead they moved the engines closer to the body. * Moving the engines closer to the body increased the pitch-up characteristic at high AOA. Not so much as to make the plane unsafe (the 757 has a more aggressive pitch-up characteristic). But enough to make it sufficiently different from other 737 to invalidate the type rating. * Boeing adds MCAS to augment the pitch-up and make it handle like other 737. They get their type rating. * MCAS software validation happens with the assumptions that it's not a flight critical system, so constraints are relaxed. It passes. * Flight testing reveals that MCAS needs significantly more pitch authority to do its job. It's updated to get that pitch authority. MCAS now becomes a flight critical system after these changes, but is not re-evaluated as one. The airframe is fine. If Boeing gives up the 737 type rating and drops MCAS, they could have the fleet back in the air within a few weeks after pilots train for it. It just would cost their clients a lot more than originally promised and be a financial disaster. https://www.youtube.com/watch?v=CD0JabYjF3A&t= https://www.youtube.com/watch?v=CD0JabYjF3A&t= https://www.quora.com/Is-the-737-Max-supercritical-that-is-inherently-unstable-and-unflyable-without-constant-computer-intervention https://www.quora.com/Is-the-737-Max-supercritical-that-is-i...
- Zigurd 7y ago
  This is just a bit circular. The 737 MAX was designed so as to keep the type rating. The design would be different, and very likely fundamentally safer if keeping the 737 type rating were not a goal. A perverse incentive from the start. So I would not dismiss the claim that the 737 is "fundamentally flawed."

A Faustion proposition -- they're going to release software updates from here to the apocalypse yet none of them will succeed in winning back anybody's trust; they should implement a code freeze until hell freezes over

rrss 7y ago

How do you know the airframe is fundamentally flawed? ("the engines are too big" is not an answer).

dboreham 7y ago
The wings are too low?
notjustanymike 7y ago
Keeps crashing into the ocean
toomuchtodo 7y ago
If the airframe isn’t flawed, fly it without MCAS. With Boeing management onboard. Surely you don’t need to dynamically adjust flight dynamics without the pilot’s input or knowledge if the airframe is sound. It’s realistic to build aircraft where software is required to fly said aircraft depending on the flight dynamics, and the pilot(s) are fully aware of what’s running. But that changes the type rating and blows Boeing’s regulatory sidestep out of the sky.
- TylerE 7y ago
  God it's frustrating seeing people here talk about aviation. Flight computers are a fundamental part of normal aeronautical design. Asking Boeing to fly a Max without MCAS would be like asking you to write a bug free C++ program... with a compiler with no error messages or validation.
  - toomuchtodo 7y ago
    [removed] Other sibling comments are of higher quality.
    - TylerE 7y ago
      Better not ever fly on an Airbus then, either. https://en.wikipedia.org/wiki/Air_France_Flight_296 https://en.wikipedia.org/wiki/Air_France_Flight_296 https://www.telegraph.co.uk/technology/9231855/Air-France-Flight-447-Damn-it-were-going-to-crash.html https://www.telegraph.co.uk/technology/9231855/Air-France-Fl...
  - windexh8er 7y ago
    The MCAS was a workaround implemented as a stopgap, no? How does this fall under the broad category of a flight computer as you've stated? What other airliners have been retrofitted with similar systems? Why doesn't a non-Max 737 need MCAS?
    - ethbro 7y ago
      No. It was a software fix put in place to satisfy a regulatory requirement under specific, known flight conditions. The following planes (among others) all translate flight inputs. Airbus A320, A330, A340, A350, A380; Boeing 777. https://en.m.wikipedia.org/wiki/Flight_control_modes https://en.m.wikipedia.org/wiki/Flight_control_modes A non-Max 737 doesn't need MCAS because it already behaves like a 737. Essentially, most replies on this boil down to people being shocked (shocked!) that computers are currently helping all planes fly. I'm not sure how they thought AEs were getting efficiency gains while physics stayed the same...
      - AnthonBerg 7y ago
        The replies do not all boil down to people being shocked that computers help planes fly. That is a willfully distorted charicature. Hundreds of people were killed due to a bad implementation of a deeply irresponsible and insensible approach to make money by skirting flight safety regulation. The bad implementation was in part software, but nobody is confusing that aspect with the whole picture. The 737 MAX does not need MCAS. Nothing needs MCAS. Boeing executives wanted the money that MCAS made them.
natch 7y ago
Isn’t the engines being not mountable at a well balanced point a big part of the answer? Which isn’t down to only the size of the engine but also the height of the wings. So yes it’s complicated but the engine is part of the picture. Although not being in the industry, I don’t know, is a strap-on engine added to a design that wasn’t intended to accommodate it technically considered part of the airframe?
- _ph_ 7y ago
  Basically no jet engine at any airliner are mounted at a point which is well-balanced in all flight situations. At level flight, the 737 MAX is also well balanced. That is just a matter of weight distribution in the machine. The problem appears at high angle of attacks, that means the force vector isn't pointing vertically down as it were only due to gravity. In this situation, the balance of every aircraft which has large engines hanging down from the wings does shift and needs to be compensated for in some way in the control systems.
djsumdog 7y ago
Like the hundreds of other comments on here mentioning how the engines were too far forward. The 737 was originally designed to be low to the ground, and rather than raising the jet and placing engines where they are on other similar planes (meaning it could no longer be classified as a 737 and requiring new manuals/training/certification), they moved them forward and adjusted for the new unexpected handling with the MCAS.
- blackflame7000 7y ago
  Raising the jet requires a wider body for the landing gear to fold up into
  - kayfox 7y ago
    The 757 sits a good 4 feet higher with the same fuselage diameter.
    - 0az 7y ago
      If I remember correctly, the 737 either doesn't have the space for longer landing gear, or there's an issue with the longer landing gear, or both. Citation needed, of course, as this is off of memory.
      - kayfox 7y ago
        It was designed lower to be easier to work with ground handling and servicing. This lead to a few different designs of plane-deployed airstairs and made it popular with Alaska Air and other airlines serving small airports. https://en.wikipedia.org/wiki/Boeing_737#Background https://en.wikipedia.org/wiki/Boeing_737#Background
    - blackflame7000 7y ago
      The 757 has a wingspan 30 feet wider than the 737. If you look at a picture of the airplane, you can see that the landing gear is part of the wing. https://qph.fs.quoracdn.net/main-qimg-0f650e809408f3962a1ed01f08a97470 https://qph.fs.quoracdn.net/main-qimg-0f650e809408f3962a1ed0...
windexh8er 7y ago
We know because hundreds of people died in the airframe. We know the MCAS was a workaround to an aerodynamics problem. Boeing has admitted this both directly and indirectly. Airframes shouldn't need software fixes to accommodate for a design failure and design failures shouldn't be allowed to fly after killing hundreds of people. How do you argue what they did and are continuing to do is just in this situation?
- skybrian 7y ago
  Uncrashable airplanes don't exist. The question isn't whether there were crashes (nobody disputes that). It's whether the problem can be fixed so that pilots can fly it safely. Given all the times the plane flew without incident (other than the two crashes), it seems this should be possible?
  - visarga 7y ago
    Yeah, it was perfectly safe except for two crashes. But that's two crashes more than I can tolerate. The problem is now the lack of public trust in their work. They might fix the software, but how to prove they're not lying again?
    - ethbro 7y ago
      The same way you prove Airbus isn't lying?
      - callalex 7y ago
        Presumably Airbus is still being watched by a regulator or two. Unlike Boeing which has not been watched as the FAA has clearly been gutted.
        _ph_ 7y ago
        The 737 MAX will be watched by all regulators world-wide. So it will be checked as carefuly, or actually even way more carefully than any competing aircraft.
tus88 7y ago
Because MCAS is required, unlike every other aerodynamically stable airplane that came before it.
- deleted 7y ago
  [deleted]
- blackflame7000 7y ago
  https://en.m.wikipedia.org/wiki/Qantas_Flight_72 https://en.m.wikipedia.org/wiki/Qantas_Flight_72
  - makomk 7y ago
    Qantas Flight 72 is probably a good demonstration of why using MCAS as a band-aid for the 737 MAX's stability issues is a bad idea. One of the key reasons that fault didn't lead to a crash that killed everyone on board is that Airbus placed much safer limits on the amount of control authority their flight envelope protections had and the altitude at which they could operate.
- danjayh 7y ago
  Airbus does it too. They have several control laws that are used to provide flight envelope protection. It was the pilot's failure to understand his plane's software that caused AF447 to crash. Essentially he didn't realize that the flight control software had changed modes, that it wasn't providing the normal handling augmentations, and that his inputs were putting the aircraft into a stall, which caused the crash. See: https://en.wikipedia.org/wiki/Air_France_Flight_447 https://en.wikipedia.org/wiki/Air_France_Flight_447 https://aviation.stackexchange.com/questions/62338/why-did-af447-never-return-to-normal-law https://aviation.stackexchange.com/questions/62338/why-did-a...
  - tus88 7y ago
    Build unstable airframes? Not outside of forward canard jet fighters. And that pilot crashed a perfectly fine airliner after he lost situational awareness and then did the one thing you should never do - pull the steering column back in a mad panic until the plane stalls.
mseidl 7y ago
The plane was built in the 50s, it was low to the ground. But Boeing wanted to fit bigger/newer/better engines on it, but they wont fit since you can't make the landing gear longer. They had to move the engines higher and much more forward.

mevile 7y ago

I've read that the problem is all the hoops Boeing is trying to jump through to keep the plane rated as a 737, not the airframe.

azernik 7y ago
That need to keep it in the 737 rating drove a lot of the airframe design.

windexh8er 7y ago

This. Given the failures, admissions and scrutiny the FAA is now under there should have been no option for Boeing to continue to band aid the airframe. Boeing should have been forced to pull the plane as "737" and recertify it as a new airframe from scratch. But why weren't they? My guess would be because Boeing would have to eat very large losses of dealing with customer lawsuits (bought an airframe that wasn't certified), would lose all future revenue as customers would cancel orders and buy airworthy competitor options, and Boeing would be forced to say they were wrong. Regardless, this still seems like the right path (recertification). It seems the FAA is still being strong armed by Boeing. Why? Put these people in prison. Shut the 737 Max down. Make Boeing face the music. They need to fail to get the point, apparently.

mrhappyunhappy 7y ago
I’m guessing doing all the things the right way would put Boeing out of business. US doesn’t want that.
- LifeLiverTransp 7y ago
  To fail to big.
joe_the_user 7y ago
Having designed the plane to be a "drop-in replacement" for a 737 and having failed at that, it seems like there's no path forward, neither more jury rigging nor certification as something else - because to make the thing like 737, they made it not like a contemporary aircraft (paper manuals is the big example). Boeing have essentially painted themselves into a very costly corner. The FAA or congress could do a "certify it just for Boeing" action and the plane might even, maybe be safe then. But how many airline customers would want to fly in it?
spookware 7y ago
Agree, using software to disguise poorly engineered design. Thanks guys.
_ph_ 7y ago

throwaway3627 7y ago

Remember Al Jazeera's 2010 report on critical defective and substandard structural parts from subcontractor Ducommun? The full scope of potential risk is ALL aircraft Boeing has designed, built, reengineered or maintained in the past 30 years. It's unknown what's hidden, poorly-designed, fragile or likely to fail because of lax self-certification up-and-down the full breadth and depth of equipment and subsystems. There's no way to prove a particular new/recently maintained Boeing plane is safe because the whole regulatory system is broken due to regulatory capture stemming from cozy, military-industrial complex corruption. I do hope Ralph Nader sues the pants off Boeing for killing his goddaughter due to their cheapness and shoddy products.

mobilefriendly 7y ago
Ralph Nader lost his grandniece.

cameldrv 7y ago

Fundamentally flawed is too strong. The airframe has some undesirable handling characteristics without augmentation. So does every jet airliner —- they all have yaw dampers at least. Aircraft designers have been solving airframe stability problems with mechanical, hydraulic, analog electronic and fly by wire systems since at least the thirties. The problem is that MCAS doesn’t fail safe. In a perfect would they would have clean sheeted the MAX, but there are numerous ways they could have made it safe, they just didn’t do any of them successfully.

sundvor 7y ago
The engines are fundamentally unfit for the airframe.
salawat 7y ago
Fundamentally flawed is absolutely an accurate moniker. Yaw dampers are workload mitigation devices; not compensatory for design flaws. Dutch roll is inherent to any controllable aircraft. Violation of 25.173 in the form of decreasing stick force response curves on approach to stall is absolutely not the same beast. Design criteria are prescriptive, and I'm not aware of any line of regulation that says an uncertifiable airframe can be made certifiable by the addition of a computer. These handling characteristics are not undesirable, they are uncertifiable according to regulations as written, and intended. Even Airbus meets these minimum design criteria at their minimum automation threshold. Boeing for some daft reason seems to be being written a pass to selectively ignore regulations around Civil Transport Aircraft certification based on some serious levels of sunk-cost fallacy. I don't believe in supporting limp-wristed minimal compliance when it comes to safety critical engineering. Not going the route of designing out the behavior requires the implementation of system after system, after system to compensate, with each link in the chain adding additional risk for failure over and above what doing it right in the first place would have created. Whitewashing wins no one but Boeing anything. Please remember that. We entrust these people to design and manufacture safer, more efficient, machines. Instead of living up to that mission, they jeopardized it in the name of optimizing the revenue/profit generating characteristics of the company. I get the reluctance to throw away a potentially recoverable airframe, but I'm dead against letting anyone whitewash over the fact the plane is more dangerous than it needed to be because someone wanted better numbers on their held stock, and was willing to put a more dangerous product on the market in able to do it.

ulfw 7y ago

That’s because they’re cheap. Software updates are cheap. Hardware updates are a problem.

kuzehanka 7y ago

Maybe HN needs a way to flag comments as factually inaccurate. This meme about the airframe being 'fundamentally flawed' or 'engines are too big(????)' or inherently unstable has been disproved by everyone in the industry including people invested in Airbus. Please stop perpetuating evening time TV show fearmongering bullshit. The eli5 explanation of the MAX 8 MCAS incident is as follows: * Boeing wanted MAX 8 to have the 737 type rating. This means it must handle and fly just like other 737. This would allow existing 737 pilots to fly the MAX 8 with no additional training. This was part of Boeing's financial advantage. * To achieve the efficiency it has, the MAX 8 has pretty large engines. Because they wanted to keep the airframe like other 737, they couldn't lift the wings to accommodate. Instead they moved the engines closer to the body. * Moving the engines closer to the body increased the pitch-up characteristic at high AOA. Not so much as to make the plane unsafe (the 757 has a more aggressive pitch-up characteristic). But enough to make it sufficiently different from other 737 to invalidate the type rating. * Boeing adds MCAS to augment the pitch-up and make it handle like other 737. They get their type rating. * MCAS software validation happens with the assumptions that it's not a flight critical system, so constraints are relaxed. It passes. * Flight testing reveals that MCAS needs significantly more pitch authority to do its job. It's updated to get that pitch authority. MCAS now becomes a flight critical system after these changes, but is not re-evaluated as one. The airframe is fine. If Boeing gives up the 737 type rating and drops MCAS, they could have the fleet back in the air within a few weeks after pilots train for it. It just would cost their clients a lot more than originally promised and be a financial disaster. https://www.youtube.com/watch?v=CD0JabYjF3A&t= https://www.youtube.com/watch?v=CD0JabYjF3A&t= https://www.quora.com/Is-the-737-Max-supercritical-that-is-inherently-unstable-and-unflyable-without-constant-computer-intervention https://www.quora.com/Is-the-737-Max-supercritical-that-is-i...

Zigurd 7y ago
This is just a bit circular. The 737 MAX was designed so as to keep the type rating. The design would be different, and very likely fundamentally safer if keeping the 737 type rating were not a goal. A perverse incentive from the start. So I would not dismiss the claim that the 737 is "fundamentally flawed."