4 ms·

And this is what I'm curious about. I can't imagine much of the original design would be left in the aircraft except for the overall shape of it. I'm guessing

And this is what I'm curious about. I can't imagine much of the original design would be left in the aircraft except for the overall shape of it. I'm guessing (remember now, basically zero aircraft development knowledge) that most tech has been updated to modern equivalents. Engines, controls, computers, ...? So what would be changed in a complete overhaul of the aircraft?

kalleboo 3y ago
> overall shape of it That's the problem. It was designed for 60s-style boarding via air-stairs on the ground (rather than modern jetways from the terminal) so it's too low down. This requires doing funky things to fit modern, large, energy-efficient engines, starting with those weird flat-bottom cowlings and ending in moving the engines back and changing their angle, which changes the flight characteristics of the plane so much it needed MCAS to compensate. > So what would be changed in a complete overhaul of the aircraft The certification, meaning pilots would need re-training since it's no longer the same plane. The MCAS thing clearly changed the plane so much it should have required re-training anyway, which is why the whole thing is so dumb.
- ZaoLahma 3y ago
  Huh, I see. So keeping it around for so long was mostly for avoiding expensive R&D and pilot re-training, and not so much for the 737 being the perfect platform to keep iterating on. Interesting.
  - Gravityloss 3y ago
    The aircraft world has its peculiarities. Lots of cases in light aviation where some crashed plane is rebuilt basically from scratch but it's cheaper from regulatory perspective to say it's the same plane, just repaired, ie reuse the tail number.
  - CaptainZapp 3y ago
    A major factor was that Airbus launched the A320 NEO and die hard, lifelong Boeing customers showed interest and even ordered the Airbus offering. Designing a completely new plane (which was considered for quite some time) would have taken far too long and Airbus would gave eaten Boeing's lunch in this important segment. So, Boeing McGivered a solution and updated a 60s airframe for modern use. To not having to recertify the plane they came up with a software hack, which they initially didn't even document and which far exceeded the capability of its original design. This[0] is a fantastic read which will leave you with a "how the fuck could they ever do that"? feeling and makes you wonder why nobody went to jail for that [0] https://spectrum.ieee.org/how-the-boeing-737-max-disaster-looks-to-a-software-developer https://spectrum.ieee.org/how-the-boeing-737-max-disaster-lo...
    - tracker1 3y ago
      I'm somewhat curious as to what efforts to design a smaller, better fit engine closer to the original form/size with better fuel economy was tried. Combined with newer materials. It seems like the flight charismatics have changed so much that pilot recertification should have been required anyway. I have worked on eLearning courses for aerospace in the early-mid 00s but have forgotten mostb of what I learned in that domain back then. It was also mostly mechanic/diagnostic interfaces (ECU, etc)
- kd5bjo 3y ago
  > It was designed for 60s-style boarding via air-stairs on the ground (rather than modern jetways from the terminal) Note that boarding a plane in the middle of the tarmac via bus+stairs is still quite common at many major European airports. Using jet bridges exclusively requires the planes to all be parked in one long line beside a building, which can never be as space-efficient as a 2D-grid parking lot.
  - agsnu 3y ago
    Isn't that mostly through mobile stairs though? Airstairs are specifically the foldable stairs built into the plane, which enforce a stricter limit on the height that the door can be from the ground. I'm sure Ryanair uses them to save on ground handling fees, but if you were designing a plane from scratch these days you wouldn't include them.
    - rsynnott 3y ago
      There actually are A320s with integrated airstairs, though it isn't as common as it is for 737s.
  - ExoticPearTree 3y ago
    + it is more expensive to park the plane at a jet bridge. Most low cost airlines prefer the air stairs + bus option because it is the cheapest option.
  - rsynnott 3y ago
    The air stairs thing is a _bit_ of a red herring. 737s are arguably designed to be ideal for them, whereas A320s do support them, but they're a bit taller and sometimes steeper than you'd like. But the taller A320 can and does operate with air stairs.
- dmazzoni 3y ago
  It sounds to me like Boeing has been making incremental changes to the 737 over the years. Clearly now it's NOT the same plane. But was there a clear point in time where they crossed the line and it really should never have been certified as the same aircraft anymore?

kalleboo 3y ago

> overall shape of it That's the problem. It was designed for 60s-style boarding via air-stairs on the ground (rather than modern jetways from the terminal) so it's too low down. This requires doing funky things to fit modern, large, energy-efficient engines, starting with those weird flat-bottom cowlings and ending in moving the engines back and changing their angle, which changes the flight characteristics of the plane so much it needed MCAS to compensate. > So what would be changed in a complete overhaul of the aircraft The certification, meaning pilots would need re-training since it's no longer the same plane. The MCAS thing clearly changed the plane so much it should have required re-training anyway, which is why the whole thing is so dumb.

ZaoLahma 3y ago
Huh, I see. So keeping it around for so long was mostly for avoiding expensive R&D and pilot re-training, and not so much for the 737 being the perfect platform to keep iterating on. Interesting.
- Gravityloss 3y ago
  The aircraft world has its peculiarities. Lots of cases in light aviation where some crashed plane is rebuilt basically from scratch but it's cheaper from regulatory perspective to say it's the same plane, just repaired, ie reuse the tail number.
- CaptainZapp 3y ago
  A major factor was that Airbus launched the A320 NEO and die hard, lifelong Boeing customers showed interest and even ordered the Airbus offering. Designing a completely new plane (which was considered for quite some time) would have taken far too long and Airbus would gave eaten Boeing's lunch in this important segment. So, Boeing McGivered a solution and updated a 60s airframe for modern use. To not having to recertify the plane they came up with a software hack, which they initially didn't even document and which far exceeded the capability of its original design. This[0] is a fantastic read which will leave you with a "how the fuck could they ever do that"? feeling and makes you wonder why nobody went to jail for that [0] https://spectrum.ieee.org/how-the-boeing-737-max-disaster-looks-to-a-software-developer https://spectrum.ieee.org/how-the-boeing-737-max-disaster-lo...
  - tracker1 3y ago
    I'm somewhat curious as to what efforts to design a smaller, better fit engine closer to the original form/size with better fuel economy was tried. Combined with newer materials. It seems like the flight charismatics have changed so much that pilot recertification should have been required anyway. I have worked on eLearning courses for aerospace in the early-mid 00s but have forgotten mostb of what I learned in that domain back then. It was also mostly mechanic/diagnostic interfaces (ECU, etc)
kd5bjo 3y ago
> It was designed for 60s-style boarding via air-stairs on the ground (rather than modern jetways from the terminal) Note that boarding a plane in the middle of the tarmac via bus+stairs is still quite common at many major European airports. Using jet bridges exclusively requires the planes to all be parked in one long line beside a building, which can never be as space-efficient as a 2D-grid parking lot.
- agsnu 3y ago
  Isn't that mostly through mobile stairs though? Airstairs are specifically the foldable stairs built into the plane, which enforce a stricter limit on the height that the door can be from the ground. I'm sure Ryanair uses them to save on ground handling fees, but if you were designing a plane from scratch these days you wouldn't include them.
  - rsynnott 3y ago
    There actually are A320s with integrated airstairs, though it isn't as common as it is for 737s.
- ExoticPearTree 3y ago
  + it is more expensive to park the plane at a jet bridge. Most low cost airlines prefer the air stairs + bus option because it is the cheapest option.
- rsynnott 3y ago
  The air stairs thing is a _bit_ of a red herring. 737s are arguably designed to be ideal for them, whereas A320s do support them, but they're a bit taller and sometimes steeper than you'd like. But the taller A320 can and does operate with air stairs.
dmazzoni 3y ago
It sounds to me like Boeing has been making incremental changes to the 737 over the years. Clearly now it's NOT the same plane. But was there a clear point in time where they crossed the line and it really should never have been certified as the same aircraft anymore?