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> The FAA cited a long litany of concerns, including a serious flight control incident during a test flight on Dec. 8, 2020, when the plane experienced an “unco

• Aperocky 5y ago
  What could go wrong if we just fire all the programmers that make too much and outsource the software?
  • lawless_c 5y ago
    The programmers are just trying to patch what once again is likely a hardware problem. If it's like the MAX the real issue is the flight characteristics
    • _ph_ 5y ago
      Basically every modern jet aircraft with relatively large engines has some sort of MCAS system. If you raise the nose of such a plane the balance does shift. This isn't a form of an aerodynamic error, it is a consequence of having large engines hanging off your wings (a lot of classic airplanes have the engines in or very close to their central axis). If you want the appropriate feedback in the steering column, you have to compensate for the shift. Airbus does it as well.
      • amelius 5y ago
        What is the advantage of the engines further from the central axis?
        • smegcicle 5y ago
          iirc that's another term for larger, more efficient engines hanging lower from the same wings
        • dotancohen 5y ago
          Time, money. They don't need to redesign the wings to accommodate the newer, larger engines.
          • coredog64 5y ago
            There's only so much room for the landing gear. Larger diameter engines require longer landing gear. Increasing the space given to landing gear requires changes to the wing box. Changes to the wing box is fundamentally a wing redesign.
            • Gwypaas 5y ago
              Which is why the A320 is designed to be loaded with conveyors. This means it has no problem accommodating an even larger nacelle than the 737 in a regular position instead of the up and forward the 737 Max resorted to. Even the previous generation 737 was running into this issue and that's why they went with the distinct oval nacelles.
        • _ph_ 5y ago
          The main driver is the desire to make engines bigger, thus more fuel-efficient. The fuel savings of the newest engine generations are significant. If you hang engines from your wings (I assume that has practical reasons, it is easier to hang the engine than include it into the wing, it is also easier to maintain), larger engines mean engines further from the axis. That applies to all modern airplanes which share this configuration. A complete redesign of the 737 wouldn't have made this go away either. However the goal of keeping the same type rating made the especial design of MCAS necessary.
          • missedthecue 5y ago
            Non-engineer here. What's wrong with taller landing gear to provide more clearance?
            • hasperdi 5y ago
              In 737 case, it means redesign of the landing gear system, fuselage modifications, recertification, retraining, new support system requirements eg. Higher stairs, cargo support equipment etc.
              • himinlomax 5y ago
                You also can't put longer main gear: as they fold inward, they have to attached at points separated by over twice the height. If you move them apart, you have to make the center fuselage as well as the root of the wings much stronger. That's a much bigger change than anything else.
            • adgjlsfhk1 5y ago
              Taller landing gear makes loading the plane (especially with luggage) much harder.
            • himinlomax 5y ago
              I believe they altered the landing gear so it extends upon deployment, giving it a bit more height, but that's not enough. They can't just put longer legs, there isn't enough room. There's stuff there (cables, devices, bulkheads ...) and moving them requires a significant redesign. For the main gears, they would have to be attached further away from the center lest they bump into each other, which means the wings and fuselage would have to be stronger to accommodate for it. Very quickly you're just designing a new plane.
      • dundarious 5y ago
        MCAS-like systems exist elsewhere, but MCAS specifically is worthy of criticism, as both an engineering failure and more importantly IMO a management failure. Specifically with regard to the flight characteristics, MCAS is a band-aid on a problem created by cost-minimization -- the desire to avoid a hardware redesign (to properly accommodate the larger engines) and/or a re-certification.
        • _ph_ 5y ago
          Of course, the actual implementation of MCAS was a disaster. Especially, that they didn't deactivate it automatically on AOA disagree, that on top of that the screen signal for AOA disagree was not shown due to a separate issue and of course that late in development MCAS was given more control authority than initially planned. My point just was, a complete redesign of the 737 still would have to deal with the same aerodynamic issues as the 737 MAX, as they are rather fundamental to this kind of jets. But indeed, it would have been easier to deal with it with a new design. It is less mentioned, that shortly after the MAX crashes, Airbus mandated that in some planes the last rows were kept empty until some software updates were deployed. So they seem to have discovered some boundary conditions they were not happy with and decided to be rather safe till they augmented the software.
          • FabHK 5y ago
            > late in development MCAS was given more control authority than initially planned ... without triggering re-evaluation of the seriousness/consequences of failure. That meant that failures of MCAS were considered unproblematic, which meant that lower levels of redundancy were deemed acceptable. Quite a process/management failure.
            • _ph_ 5y ago
              Well, technically the failures of MCAS should be unproblematic, as the stabilizer runaway protocol is well trained for any 737 pilot and would cope with a MCAS misfunction. The problem is: in the two crashes the pilots either completely failed to follow the protocol (Lion Air) or to late and failed to recover (Ethiopian Airlines).
      • wyldfire 5y ago
        The bonkers thing seemed to me to be having the notification and/or override as an opt-in feature you could buy. Southwest didn't want to train pilots and newly visible behavior requires new training. No surprise that airlines elsewhere in the world also skimped on the "optional" features to the doom of the passengers and crew.
        • carl_dr 5y ago
          The opt-in feature you mention was for a disagree alert for the plane’s angle of attack sensors. But, MCAS was only ever using a single angle of attack sensor as its source of truth, so if there was a fault in that single sensor, MCAS could activate at normal attitudes. But the real problem was that Boeing hadn’t documented MCAS, to avoid the requirement for pilots to obtain type certification for the MAX (so any existing 737 pilot could to fly it without additional training - and it wasn’t just Southwest objecting to this training), and to avoid a full FAA certification process for the MAX. So on an MCAS activation, even if they had had an AoA alert, pilots would not know how to instinctively deal with it. (I don’t doubt an AOA disagree alert would give invaluable information allowing the pilots to rule out most failures, which when only a few thousand feet high would maybe have saved both planes.) On the previous day to the Lion 610 crash, the incident aircraft suffered an MCAS activation and fortunately a pilot in the jump seat realised what was happening and what was needed to deactivate it. It seems being sat behind the trim wheels (so he could see they were moving) and not wrestling to keep the plane in the sky at the same time was needed for that to happen. It must have been terrifying.
          • coredog64 5y ago
            737 trim wheels are very visible and very loud. The noise and motion they create have been a joke within the 737 community for at least 20 years.
      • Gravityloss 5y ago
        Yes, it's the aerodynamic lift from the big engine fans that was the 737 Max issue, according to Aviation Week. Fans have gotten bigger as engines have improved and the bypass ratios and fuel efficiency has gotten better. Think of the engines as a big horizontal stabilizer but it's at the front, in front of the center of gravity. Normally it doesn't do much anything since the angle of attack is zero. But if you increase pitch, it will increase nose-up momentum. For some reasons it's not common to put the engines further back. DC-9 style, on the sides of the rear fuselage might work. Or maybe over the wing and slightly to the rear, like Hondajet.
      • himinlomax 5y ago
        The difference is that all Airbus planes since the 1980's A320 are built around computerized flight commands, so the code paths involved are exercised constantly. MCAS only triggers occasionally, meaning if it has a bug, it only shows up at the worst possible time. Airbus planes also have double redundancy (three inputs and computers) for all those systems, where MCAS had none by default.
    • landemva 5y ago
      Won quoted as, “The technical data required for type certification has not reached a point where it appears the aircraft type design is mature ..." The 737MAX should have gone through a new type certification, but didn't to allow for less pilot retraining. FAA failed to properly serve the public. New type cert finds flaws and saves lives.
    • WalterBright 5y ago
      > If it's like the MAX the real issue is the flight characteristics The real issue was the reliance on one sensor coupled with too much authority give to MCAS and inadequate failure analysis. And pilots who did not read, remember, or follow the 2 step recovery process in the Emergency Airworthiness Directive sent to all MAX pilots.
      • WalterBright 5y ago
        I always get a negative reaction for mentioning the Emergency Airworthiness Directive sent to all MAX pilots. Media accounts never mention it, either. The Boeing Emergency Airworthiness Directive says: "Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT." https://theaircurrent.com/wp-content/uploads/2018/11/B737-MAX-AD-1107.pdf https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA... For those who are skeptical of mainstream media fake news on the topic, here's the official final report on the Lion Air crash: 2018 - 035 - PK-LQP Final Report http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2018%20-%20035%20-%20PK-LQP%20Final%20Report.pdf http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2018%20-%20... I also recommend the recent Aviation Disasters episode on it. While shallow, because it has to fit in 40 minutes, I was shocked that it was surprisingly accurate. Kudos to the Smithsonian channel. I wouldn't be surprised if AD waited until that report was released before doing the episode, so it would be using verifiable facts.
        • DangitBobby 5y ago
          What are you trying to say, exactly?
          • WalterBright 5y ago
            Not sure what you find confusing about it.
  • dundarious 5y ago
    Not sure if you're being serious, and while it hasn't been tried AFAIK for the flight software specifically, but cost-minimization and outsourcing has been credited as the major sources of Boeing's safety problems for the last decade (737 MAX, 787 Dreamliner, 737NG). Doing more of it would be neither a change of course nor an improvement IMO.
    • eganist 5y ago
      > Not sure if you're being serious, and while it hasn't been tried AFAIK for the flight software specifically, but cost-minimization and outsourcing has been credited as the major sources of Boeing's safety problems for the last decade (737 MAX, 787 Dreamliner, 737NG). Doing more of it would be neither a change of course nor an improvement IMO. I hear you, but I suspect aperocky was criticizing that exact approach. I.e it felt like sarcasm.
      • dundarious 5y ago
        Makes sense, I was genuinely 50/50 about it being sarcastic, but I probably should have been more confident of it, and at the very least should have given more credence to that interpretation than "not sure if...".
        • Dylan16807 5y ago
          I'm honestly confused that you give it 50/50. Even ignoring the context, the "we" in "what could go wrong if we" only works if it's a rhetorical question. And from there, analyzing it as a rhetorical question, it seems obvious to me that the implied answer isn't "nothing". Do you disagree with either part of my reasoning?
          • dundarious 5y ago
            On HN, especially if there's talk of labor (or god forbid, unions), there are often some pretty extreme opinions. And I said I shouldn't have given it just 50/50 odds. I don't see the point in continuing this postmortem.
  • dotancohen 5y ago
    Actually, the responsible bit of software was already outsourced. There was an HN thread on that some time ago.
    • Aperocky 5y ago
      Yes this is what I'm referring to.
  • _ph_ 5y ago
    This is really a crucial point. I am a software developer in an engineering company. What is essential for my job is not only my programming skills, but also a decent understanding of the engineering I deal with. This can only be achieved by working long enough in the job, be it an engineer who picks up programming or a software developer who learns the engineering involved. This is of course much more expensive than picking up any contractor, who might be brilliant at programming, but lacks the domain knowledge that only grows over time, but it is a good way of having more eyes spotting potential spec issues.
    • rbanffy 5y ago
      I really fail to understand the logic that may make someone to think a software engineer, however brilliant, can write software for a domain they don’t understand.
      • slipframe 5y ago
        Wishful thinking.
      • Aperocky 5y ago
        If this brilliance can be translated to understanding in other fields, which usually it can. This requires studying, which firms simply tries to avoid. I am a software engineer now, but my major was mechanical engineering, I can barely remember any of my coursework, but I understand how physics work in general, and a small bonus on how to disect a system. Nobody can know everything in today's world and that's why common engineering/sense training is so important IMO.
        • vidanay 5y ago
          Similar. I used to design automation equipment, but I've switched to software development. I'm still closely connected to the mechanical side though. More than once I've had to explain to someone who is a competent programmer that they can't accelerate mass x at rate y.
      • pjmlp 5y ago
  • ricardobayes 5y ago
    What the cookie-cutter management doesn't understand is 100% of the company's value goes home after 5PM.
  • throwaway713 5y ago
    I suddenly became afraid of flying when I started working for one of the companies known for having some of the best software engineers in the world and seeing how many bugs made it into prod. I can't imagine who is programming the flight computers for Boeing and what they're being paid. It's gotten bad enough that I refuse to fly on any plane that was released in the last decade. At least the older planes have some decent trip statistics to back up their safety.
  • WalterBright 5y ago
    The MCAS problem had nothing whatsoever to do with outsourcing. The problem was in the specification of its behavior.
    • metalforever 5y ago
      This does appear to be related to bad engineering or engineers that do not understand how to program safety systems.
      • WalterBright 5y ago
        Of course, but the specifications are normally written by Boeing, and the implementation is outsourced. The reason is the system as a whole has to function, meaning the spec has to be written by the team that has knowledge of the whole system. MCAS interfaces with quite a few other systems on the airplane.
        • _ph_ 5y ago
          Even a good team can convince itself, that it is right. It would have added a "second set of eyes", if the implementors of MCAS had their own expertise in aviation. No guarantee, but a chance of spotting the problems with the spec.
  • Guest42 5y ago
    It is my understanding that in aerospace much of the software is outsourced and is then QAed by internal contractors.
• vmception 5y ago
  My understanding is that they are trying to make planes that are too big to actually fly without continual software correction Can they just not do that?
  • VBprogrammer 5y ago
    The 777 is fly by wire so it wouldn't be a good idea.
  • deergomoo 5y ago
    My understanding was that they’re trying to use software to make their new planes fly like their old planes (at least that was the reasoning for MCAS in the 737 MAX). In super basic terms, if the new plane doesn’t fly like the old plane, all the pilots need to be retrained. This is a significant expense that could make a serious dent in sales. I don’t think it’s anything to do with size, there are larger planes than the 777X that are perfectly safe (and of course, the 737 is pretty small as far as airliners go).
    • LatteLazy 5y ago
      Isn't there also some weird requirement that pilots only fly one/two airframes at a time? So training for a 777 means your can't fly 747 or something else anymore?
      • sp332 5y ago
        I don't think so. But it was easier to sell to airlines if it didn't require retraining.
        • Dylan16807 5y ago
          It seems like there's a very strong incentive to avoid retraining coming from somewhere, at least. Surely that's not just airlines being stubborn?
          • 5y ago