In addition, there's no evidence that Airbus planes have design flaws as bad as MCAS. So why fly on a 737MAX when any other plane out there is safer?
https://en.wikipedia.org/wiki/Qantas_Flight_72
Edit: To be clear, while this was 10 years ago and noone died, this incident seems to me to be a bit worse than the issues with the 737 MAX in that with the A330, there is no shutting off the systems that caused this issue, as they are part of the flight controls. Fortunately the causes were investigated and while the exact cause of the issue was not identified, the computer systems were updated to deal the fault scenarios identified in the investigation.
In a fly by wire aircraft.
Well no one can fly one right now as they are all grounded. However, once they get approval for a fix from all countries, the airplanes get updated with said fix, and the pilots get whatever training required for the fix and thus can start flying again, why not fly them? Presumably, that failure type should never happen again and its record seems fine outside of this 1 problem.
That's a big assumption. The planes are already unmanageable, even if MCAS is fixed: human pilots aren't strong enough to turn the trim wheels manually in an emergency.
>and the pilots get whatever training required for the fix
I don't see how this is possible without forcing pilots to get a totally different type rating for this aircraft. That's the whole reason they put MCAS in there in the first place: to avoid a different type rating, which would require an expensive add-on certification.
Operation of the trim wheel and the forces acting on it are the same as the 737 NG. If this worries you, you shouldn't take any 737.
The wheel in that video can not be turned manually because of the aerodynamic forces acting on it. Pilots are trained extensively to recognize a runaway trim condition and stop it before it gets to that point. At lower angles a roller coaster maneuver can be used to turn the trim manually.
The MCAS was definitely poorly designed but everyone is downplaying the poor pilot response and maintenance issues involved with the crash. Lion Air pilots flew a plane with a stall warning going on for a full hour instead of landing ASAP. Then when the plane got to the ground, the company saw it fit to fill it up with people again and fly it with a critical system malfunctioning due to unknown causes.
They dodged responsibility because boeing had a serious design issue but their behavior was criminal, even more so than boeing. I wouldn't fly any lion air plane.
The speaker talks about trimwheel behaviour. Pilots train for runaway stabilizer trim, but that's continuous movement of the trimwheel, faulty MCAS looks much like regular speedtrim. Also, activating electric trim activates another round of MCAS. Obviously you shouldn't take Lion Air, but after this talk Boeing doesn't look safe now either.
The exception being modern fly-by-wire planes that simply don't have an option of manual override.
The speaker talks about trimwheel behaviour. Pilots train for runaway stabilizer trim, but that's continuous movement of the trimwheel, faulty MCAS looks much like regular speedtrim
Obviously you shouldn't take Lion Air, but after this talk Boeing doesn't look safe now either.
Also, the AoA-vane was replaced with a faulty part, and never retested after install if I recall correctly. A procedure complicated by the fact the plane would have had to have been started, shutdown, then restarted since the Flight Computer switches from side-to-side each flight.
So a maintenance tech may have accidentally tested the wrong computer assuming the documentation wasn't up to snuff. Can't say as I've seen that part of the documentation myself; but considering they left MCAS out of the pilot docs, I somehow doubt that it was greatly elaborated on in the maintenance docs as well.
With all the different government agencies going to be manually inspecting the updated plane themselves, the MCAS problem is going to be put under a microscope by dozens of different countries and if they do approve it and deploy it, then I am going to take there word for it as having mitigated the MCAS problem and won't care about stepping on a 737 max as its track record outside of this 1 problem is fine.
If it does not get approved or deployed, then who cares because you won't even have the option to fly it as it will stay grounded. Regardless of what happens, checking what plane I will be flying on will not impact my decision when choosing flights.
What if it does get approved, but only by some countries? So, for instance, suppose the US approves it, but China and the EU don't? Then, it probably won't stay grounded, because this plane is usually used for shorter-distance travel. Southwest Airlines, for instance, exclusively uses 737-type aircraft, and all their travel is domestic US, so an EU ban wouldn't affect them at all.
I for one wouldn't feel too confidant about the FAA approving this plane with the EU regulators refusing to, considering what a criminally-negligent job the FAA did in approving it in the first place.
"ignorance is bliss"
If you knew how much software went into a car vs. an airplane, you might think twice. Airplanes seem more complicated than cars, but software-wise they are much simpler. Cars have millions upon millions more SLOC than airplanes. You think MCAS is bad, how about cars that have sudden loss of steering, emergency brakes that mysteriously engage, or a throttle that can't be disengaged?
Serious design flaws in airplanes are these big dramatic events. Serious design flaws in cars pop up in the news every day, and we just ignore them [1][2].
[1] https://www.consumerreports.org/car-recalls-defects/mazda3-r...
[2] https://www.consumerreports.org/car-recalls-defects/more-car...
>how about cars that have sudden loss of steering
Citation needed. I've never heard of a car having this problem, and it's generally impossible because there's a mechanical link between the steering wheel and the front wheels.
>or a throttle that can't be disengaged?
Citation needed. I've never heard of this happening where it's been proven to be real and not a publicity stunt. All the problems with "unintended acceleration", including on Toyotas a while back, have been shown to either be people using aftermarket carpet mats, or even people faking it. What's more, turning off the car in an emergency is not hard, even in push-button-start cars. Now of course, we can blame some wrecks from faulty systems on poor driver training, drivers who just aren't very good, drivers who can't handle an emergency, etc. This simply does not apply in an airplane: pilots go through a LOT of training to get that job, so if they crash anyway, that points to an unforgivable mistake in engineering or manufacturing.
https://www.usnews.com/news/national-news/articles/2018-09-1...
https://www.ncconsumer.org/news-articles/ford-issues-recall-...
As I understand it large trucks existed prior to power-assist, they just hired big strong chaps who could wrestle the steering.
We probably don't want (and Boeing doesn't want) to make 737 Max certification have a "Physical strength check" where you need to exert so-and-so much turning force for so-and-so many seconds or you can't fly their plane. So probably trim wheels need a re-think, whether that happens as part of the 737 Max work, its immediate aftermath or not for years because this incident scares manufacturers away from changing anything about trim.
Seismic shifts in safety considerations do happen, we haven't seen the last of them. And they aren't always ultimately for the better. Titanic had a few effects, many of them really good, but one notable one is that it pushed the narrative that you need to provide and test a LOT of lifeboats on an ocean liner. Titanic, as you can probably all recite, did not have enough lifeboats. But in practice lifeboats are very much a last resort for an ocean liner captain. You've got a whole lot of civilians who are incompetent at sea at the best of times, probably panicking and now you're trying to successfully get them into smaller boats under supervision of a relatively smaller number of crew. Some of them are likely to be injured or even die. A ship's master would prefer _anything_ over putting passengers into lifeboats, except them all drowning. Almost always the sensible course of action, taken by the ship's master, will be to take the still working ship to any port and unload the passengers. Yes even if the ship is somewhat on fire, or has grave engine problems, almost anything except actually sinking right now.
Meanwhile just owning the lifeboats means your crew have to keep testing them and servicing them, each time also has a chance of injury or death as crew fall into the water, boats fall on the crew, and so on. So owning a suite of lifeboats for your ocean liner (which you weren't planning to crash into an iceberg at any time) is probably a net negative in terms of injuries and deaths.
Actually, I think they absolutely should. And then it should be made illegal to have a plane that has any such requirements, so these planes should be deemed unairworthy, and Boeing should be forced to scrap them. Either that, or female pilots should be able to claim discrimination, and every female or otherwise not-strong-enough pilot should get a free lifelong chief pilot salary as part of the settlement.
Basically, this plane should never have been built. It's a 1960s design, and because of crappy regulations that allowed this, Boeing kept making this 1960s tech because it was "grandfathered". Newly-built planes should not be allowed just because they were OK 50 years ago, when they aren't good enough according to modern standards.
Many modern cars have computer control of brakes, accelerator and even steering, so a software flaw could stop you in the opposing lane just as you start to pass a car, or accelerate and steer you into a bridge pillar (and since that car was already steering the car before that, the driver may not be able to react in time)
Steer by wire is becoming much more common. It’s already in luxury cars and, like most features, will probably eventually trickle into economy car designs
I did see one source indicating a roughly 25% increase in steer by wire by 2026, but it’s behind a paywall so I’m not sure how good that source is. According to a Tesla forum, there’s still a mandate for mechanical linkage
EPS has been on production cars now since the 1990s, and I've never heard of any software problems with those at all. In fact, it's probably been more reliable than hydraulic systems since it doesn't have so many moving parts, just an electric motor, and no hydraulic fluid to leak or get contaminated (due to not being replaced on time, a common thing for people to skip on maintenance).
Steer-by-wire is a no-go for now, because it's illegal to not have a mechanical linkage. That might eventually change when we get driverless cars, but there's no sign that those are coming nearly as quickly as many people used to think; there's just too many problems with them.
“Recalled products do not contain the updated software that mitigates the effect of the condition. When the system voltage drops below 8.8 volts for more than 1 second — e.g., during low-speed turns — EPS assist is disabled”
Honda has had similar recalls.
I don’t know if that can be used to claim software caused the initial hazard but does indicate software is used to mitigate safety issues with the implication that software failures can lead directly to hazards
This isn't very different from old hydraulic-assist cars that also had the assist die or be too low when there was some problem (fluid too low, pump failure, belt failure, etc.). Was it ever a big problem? No, not really. If your power steering fails in a parking lot, it's a pain, but you're already barely moving, so you just stop. At worst, you might have a minor fender-bender.
I don't see how this is a software problem; this is an electrical problem. The only software issue here is the decision to shut down the EPS instead of bringing it back online when the system voltage goes high enough.
Personally, I'd say the fundamental problem here is actually the fact that cars still have 12V electrical systems, and batteries that are really meant for starting only, not for continuously supplying heavy electrical loads (like EPS). Carmakers should have gone to 42V or 48V systems ages ago.
I don’t know the specifics of the system safety analysis but if the software is used to mitigate a hazard, it’s usually considered safety critical. In this case, if it shuts the EPS off, or fails to bring it back online, it it would significantly affect the vehicle handling dynamics. Again, I don’t know their classification scheme but I would assume the steering is a safety critical system. Some reports claim the vehicle lost all handling control, but I’m a little skeptical of that claim.
In any event, I wouldn’t consider it no issue. Recalls cost a lot of money. In the GM case it affected 1MM cars. I didn’t look up the cost of each fix, but I wouldn’t be surprised if it cost nine figures. I doubt they would go forward with a recall of that magnitude for a trivial issue.
I could see the same rationalization for MCAS. The system safety analysis didn’t claim an MCAS failure was catastrophic and they already had a procedural mitigation in place if it did fail. It wouldn’t take much to convince someone that such a recall fix was no big deal. This is part of the problem with systems using safety critical software
I'm not familiar with the specifics of that case, but having a low system voltage is more likely at parking lot speeds because the alternator isn't turning very fast, whereas at speed the alternator should be generating enough power to run everything including EPS, but maybe they underspecced the alternator, so I can see it happening. Still, losing your power assist at speed is still dangerous of course, but it is recoverable, and it's nothing like having a critical system fail in an aircraft. Failures in cars are always safer than in aircraft, because you're already on the ground. This is why safe design is so important in aircraft: if something goes wrong in a car, it might result in a wreck of a few vehicles at worst (multiplied by the number of cars experiencing that failure), but many times tragedy is avoided because the driver just needs to steer away from traffic and avoid running into something too fast. In an aircraft, there's no such thing as a "fender bender"; crashes are usually fatal, and they usually carry dozens to hundreds of passengers.
>Recalls cost a lot of money. In the GM case it affected 1MM cars. I didn’t look up the cost of each fix, but I wouldn’t be surprised if it cost nine figures.
That seems high: you're assuming each car cost $1000 to fix there. That's a lot of money to fix one component; at that volume, the part probably cost well under $100 each, and as another poster noted, the dealer labor required was pretty small.
I was estimating at $100 per fix (since it's just the labor cost of software). At roughly $120 per labor hour multiplied by 1MM vehicles is where I came up with the nine figure mark. At $1k per fix, it would be in the 10 digits. Regardless, it was overshot and I corrected it with the details in a reply (since I couldn't edit the original). It only comes in at 0.5 hours per fix. Not chump change but the decision to fix it may also have been influenced by the Toyota accelerator and GM ignition recalls that got a lot of press.
And, as you pointed out, it was a systems interaction problem. Losing power steering at speed isn't great, but it's recoverable (maybe less so if you're weak and you're driving some big stupid SUV, rather than a small economy car), and losing power brakes is also bad but recoverable because you have enough vacuum in the system to do a full stop (but only 1 usually), but tie them together, at speed, and also (worst of all) lock the steering wheel, and you have a recipe for disaster. This is far, far, far worse than losing your power steering assist at parking-lot speeds.
This is the traditional way to deal with system hazards. What has been talked about is the need for changing the way we think about software failures on safety critical systems, distinct from traditional failure mode approaches.
"The result is that software-related accidents involve a new type of accident, which can be called a component interaction accident: None of the components fail (all satisfy their specified requirements) but the problems arise from dysfunctional interactions among the components."[2]
But one-off car fatalities that kill 1-3 people happen regularly and they add up. The self-driving variety pop up with the highest visibility but if you go searching you'll find tons of accidents where brake failure at highway speeds cause a fatal crash.
I do concede that distracted driving and alcohol play a much bigger role in the large amount of car fatalities than software flaws. But I still stand by my original assertion that you are more likely to die due to the effects of a software flaw in your car than due to a software flaw in the 737 Max.
Yes, there's the self-driving stuff, and there have been some egregious examples, but those systems also save lives by preventing accidents. Lane departure warnings, automatic braking, and electronic stability control all, on the balance of things, make driving much safer.
Braking systems have been partially modulated by software for decades, i.e. ABS, TCS, ESC.
Additionally, other software controlled systems can induce mechanical issues. For example, in the case of the Toyota unintended acceleration debacle, an engine at WOT typically does not produce vacuum. However, power-assisted brakes almost universally are vacuum-powered. So, if the software-controlled throttle gets stuck wide open, you lose power-assist to the brakes.
https://users.ece.cmu.edu/~koopman/pubs/koopman14_toyota_ua_...
[1]https://www.cnn.com/2010/WORLD/asiapcf/02/04/japan.prius.com...
The whole point of my comment was to put to bed the irrational fear of flying. You are still more safe travelling long distances in a faulty flight system such as the MAX than you are by car. There are just too variables to account for in cars, one of which includes increased software complexity.
Secondly, what are the exact figures you're using to show that the 737 MAX is safer than cars? And now compare it to other planes, the more realistic comparison? I'm not taking planes to places that are within driving distance. The 737 MAX was waaaay less safe than other planes.
I don’t know the same about my car, which is why I’ll take it over a Max any day, and that’s why Boeing is having to PR themselves out of this mess.