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Why is it troublesome? As someone with very limited knowledge in aircraft development, I'm genuinely curious about what more modern designs would bring to the
by ZaoLahma 3y ago
Why is it troublesome?
As someone with very limited knowledge in aircraft development, I'm genuinely curious about what more modern designs would bring to the table compared to the modern 737s, which I assume are heavily updated versions of the original 1960s design?
- consp 3y ago> heavily updated versions of the original 1960s design Isn't that the cause of many problems?
- ZaoLahma 3y agoAnd 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 agoHuh, 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 agoThe 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 agoA 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 agoI'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 agoIsn'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 agoThere 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 agoThe 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 agoIt 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?
- perryizgr8 3y ago> more modern designs would bring to the table How would we know unless they do it? Before iphone was launched someone could have made the same point about Nokia's smartphones. They were heavily updated designs of their massively popular Symbian phones. We simply didn't know what was possible until someone put in the work and innovated and came up with an entirely new design.
- ZaoLahma 3y ago> Before iphone was launched someone could have made the same point about Nokia's smartphones. For my question the phone-equivalent would be someone asking today in 2024 what is the difference between a Nokia of 2006 and an iPhone of 2024, when only knowing that you can make calls with both of them. I genuinely didn't know that the modern 737s are so much of a hack to get around regulations and save cost on R&D, and thought they were just good aircraft that were worth iterating on.
- nottorp 3y ago> We simply didn't know what was possible I'm sure a few PalmOS owners wondered why they don't make the scroll bars fingerable and add a cell phone ;) But points to Apple for figuring out you don't need a stylus to write either and you can scroll from anywhere. And for, you know, building a device. I thought of a primitive form of it but it never occured to me to do it.
- jen20 3y agoA PalmOS cell phone - the Treo - was featured in the original iPhone keynote. I had two, the first (600) was OK. The second (650) was abject garbage - it would crash just sitting waiting for calls.
- nottorp 3y agoI know about the Treo, but I never got one. If i remember the first reviews correctly, it was a cell phone bolted onto palmos but totally separate somehow. It didn't 'smell good'. I've had quite a few non phone PalmOS devices though. I think I'm still keeping a non functional Sony Clie [1] in my nostalgia stash. And maybe a Zire Z22, but I may have thrown that away. [1] https://en.wikipedia.org/wiki/Sony_CLI%C3%89_NR_Series https://en.wikipedia.org/wiki/Sony_CLI%C3%89_NR_Series
- rob74 3y agoThe original 737 was the smallest aircraft in Boeing's passenger jet family, behind the four-engine 707 (which was already becoming obsolete at the time and was eventually replaced by the 747) and the three-engine 727. I mean, this was the original 737 model: https://en.wikipedia.org/wiki/Boeing_737#/media/File:Boeing_737-130,_Lufthansa_AN2056613.jpg https://en.wikipedia.org/wiki/Boeing_737#/media/File:Boeing_... - Lufthansa used it as a "CityJet", which is its regional brand! That's why the 737 sits so low to the ground, so it can be loaded and unloaded with simple equipment (or even without equipment) at small regional airports. And that proved a major issue when more efficient turbofan engines with ever higher bypass ratios (-> bigger diameters) came about, so they had to use various tricks to acommodate these engines, and the latest trick (MCAS) then backfired tragically. Besides that, the things Boeing can do to update the 737 are limited, or else the FAA might come along and say "this is not your grandfather's 737 anymore, it needs a new type certificate!".
- MilStdJunkie 3y agoFalse Equivalence is one of a big sawhorses I bring out for why things suck so much more now, in aerospace and defense generally. For the past 10-15 years, we've had mechanisms for quantitatively ballparking equivalence in pools of supportable assemblies and spared parts - but generally, no one wants to touch that. The purchasers of enterprise solutions (CAD, PDM, etc) want equivalence to be ultimately a financial decision, not a question solved by materials, interfaces, fluid dynamics, frickin' electricity, etc. Your problem there is . . well, jeez, look around. You're treating completely different products like they're the same thing. Not exactly a new problem, either, but it sure is interesting how it's compounded since the great "financialization" experiment in American capitalism circa 1974, and with a whopper of a sequel post-2008. I am out of my sandbox here, but if I was a betting man, I would put the root cause of this nonsense in this bucket, i.e., lowering apparent risk (by making things look similar) so as to meet requirements of issuing larger financial instruments (bonds, etc).
- s1dev 3y agoA few things come to mind from more modern aircraft like the 787/A350: Fly by wire (flight envelope protection), electronically actuated control surfaces (less hydraulics / reduced complexity), bleedless engines (greater efficiency), greater use of composites (less weight), modern wing design using computational modeling/optimization (possibly more efficient), and essentially as large of a turbofan fan as you would like
- hooby 3y agoEngines got a lot larger over time, more fuel efficient, more reliable, etc. On a 737 those engines cannot be placed in an ideal position, because that would mean they'd clip into the ground. The engines are being put above and I think in front of (might be wrong there) where they should be for maximal flight stability. The original 737 was self-correcting - meaning that if for example the aircraft stalled, the resulting forces would cause the nose to dip down, pulling the plane out of the stall automatically. The newer versions no longer have that inherent self-correcting ability - and instead use computer software to take over controls and pull the nose down, in case of a stall. A new airplane design could be made to accommodate much larger, modern engines, while also having the stability and inherent self-correcting ability of the original 737. But that would require changes to the overall shape and form of the plane - which will require complete recertification. By sticking to the old design, they avoid that.
- froh 3y agoELI5! thanks so much! so the crashes were because the new software was confusing to the pilots and did something unintuitive? and now they want to do another change to how the airplane behaves (interacts with) the pilot?
- deleted 3y ago[deleted]
- hooby 3y agoAfaik, the crashes were caused by the software mistakenly believing the plane was in a stall due to a single faulty sensor and pulling down the nose - while the pilots had absolutely no clue what was going on (because they never were told the software could do this), and had no way to disable/counteract the software. I believe the updated software now uses both sensors and only acts if both sensors agree (which is actually standard for such systems and should have been done right from the start) - and can be disabled by the pilots, who are now aware of it's function. But please don't trust my word... I'm no aviation export by a long stretch. For a more qualified take on this, done by an actual pilot and pilot trainer, I recommend checking out "Mentour Pilot" on Youtube. He's got a number of videos on the 737 Max and the reported problems at Boeing.
- mrjin 3y agoSolely being old isn't the problem. The early variants of 737s were solid. It became a problem with later versions with bigger engines etc: you can probably get away with some minor CHANGES without overhaul the design as long as it's still within the threshold of the original design, but those MAX variants crossed the line. Thus MACS was introduced. MACS, to some extent, was a feasible workaround if Boeing did not cut the corners by outsourcing the implementation and chose to only have one critical attack angle sensor. But if things only stop there, those two disasters could still have been avoided if the pilots were aware of the existence of MACS. But again, Boeing decided there was no need for the pilots to know it at all. After the first crashed MAX's FDR data release, I was wondering if there were something massing with the pilots but I wasn't sure. Then the 2nd crash happened and the FDR data looked almost exactly the same, I was almost certain there was some undisclosed mechanism causing nose diving. But as we all knew, Boeing denied such thing until later. You can see that in the whole Boeing had been SUPER CONFIDENT for sure, and thus I now have no confidence in it at all.
- kranke155 3y agoIts amazing you can´t prosecute some of these people for murder. 346 people are dead because of this.
- anticensor 3y agoCausation of vehicular murder, hmmm.
- kranke155 3y agoIf you constructed and sold a vehicle that was deliberately made in a way that caused deadly crashes.