The fuel control switches are behind the throttle stalks above the handles to release the engine fire suppression agents. These switches are markedly smaller and have guards on each side protecting them from accidental manipulation. You need to reach behind and twirl your fingers around a bit to reach them. Actuating these switches requires pulling the knob up sufficiently to clear a stop lock before then rotating down. There are two switches that were activated in sequence and in short order.
The pilot monitoring is responsible for raising the gear in response to the pilot flyings' instruction.
I would find it very difficult to believe this was a muscle memory mistake. At the very least, I would want to more evidence supporting such a proposition.
This idea strikes me as even more unlikely than someone shifting their moving vehicle into reverse while intending to activate the window wipers.
I suspect you've never driven an older vehicle with the shifter on the steering column.
Or a new Mercedes ;)
I've engaged my wipers when meaning to shift gears before, in my truck which has a steering column shifter. After driving the truck for years. I have ADHD and I very often let my brain go on autopilot for things I do every day, and sometimes it just does the wrong thing. It doesn't matter how complicated or "intentional" the task has to be: my brain will memorize it to the point that it can execute it on its own without me consciously thinking about it.
I think it's totally plausible it was a muscle memory thing, if the at-fault pilot's brain works anything like mine.
(Side note: I actually took some flying lessons, including going through all of ground school, and realized that my brain is just not cut out for flying. I am the type of person to "cowboy" things if I feel like they're not worth doing, and flying is an activity where the tiniest missed checklist item can result in death, so I realized I have a statistically high likelihood of crashing due to some boneheaded mistake, and stopped taking lessons.)
This could be anything: starting a car, taking off a medicine cap, typing my password, clicking around cookie warnings. If I have to do it repeatedly, my brain will be able to perform it subconsciously, and I will do it without realizing it.
For fuel cutoff switches, it doesn’t matter that there two of them in a row. If you cut off both of them every single time, and you fly every day, your brain is gonna automate that task.
Everyone in this thread thinking “these actions are temporally and physically distinct and therefore impossible for anyone to confuse” isn’t really thinking about the problem the right way. It’s not that I’m actually confusing two actions. It’s that I’m accidentally allowing my brain to perform one action when I meant to let it perform another action. “Allowing” is an important word here, because it illustrates that my brain is capable of doing this on its own without me thinking about it, and often will do it on its own, if I let it.
On some aircraft types you also have to pull it towards you before moving it to avoid hitting it by mistake.
But I agree it's very unlikely to be a muscle memory mistake.
from this article: https://theaircurrent.com/aviation-safety/ai171-investigatio...
shows you the switches on a 787. They are protected and hard to futz around with by mistake.
This is exactly how the investigations are NOT conducted. You don't find the evidence that confirms your theory and call it a day when the pieces sorta fit together. You look solely at the evidence and listen to what they tell you leaving aside what you think could have happened.
The collection of comments on this post remind me it'll just be a brand new set of random guesses until the final report is released. Or worse - the final report reaches no further conclusions and it just has to fade out of interest naturally over time.
If hearing those guesses annoys you, nobody is forcing you to read through comments on a thread of people making them! (I hope - sorry if you are being forced after all.)
That doesn't mean I will always agree with the comments (or that everyone will always agree with mine) and that's okay. It'd be a very limited value discussion if we could only ever comment when we agree. It seems exceedingly unlikely any of this has something to do with users being forced to be here though.
It’d be nice if we could only read insightful comments, and unread the wacko comments, but we can’t. This discussion has actually provided a lot of useful comments from people who seem to know what they’re talking about, but also a lot of really wild speculation.
If we decided to pin all aviation incidents on pilot errors, we wouldn't even have invented checklists (what do you mean you forgot, try harder the next time).
"Natural" pilot errors lead to lessons that can be incorporated into design/best practices. That does not seem to be the case given current understanding: no flaw in any switch design seems apparent, and it does not sound like something you could do by accident.
So "pilot error" is not the "cracking the case"-grade conclusion it is being made out to be, it is an act of investigative resignation. In the days following the crash, allegations of mixing up flaps and landing gear were floated, and they all turned out to be wrong. This is not even accounting for the fact that the pilots are not around to plead their case, and basic human dignity requires us to defend their case until evidence clearly points a certain way
This was a really disappointing incident for aviation YouTube - I unsubscribed from at least three different channels because of their clickbait videos and speculation.
Given a long enough span of time, every possible fuck up eventually will happen.
HN has somewhat democratic editorial tools and thus majority opinions on HN are very clear.
What about up on the overhead panel where the other engine start controls are?
Or (at the cost of complexity) you could interlock with the throttle lever so that you can't flip the cutoff if the lever isn't at idle
Also the fire suppression system is a different activation (covered pull handles I think)
The switches are already pretty distinct - but that only reduces failures, it can never eliminate them entirely.
> Or (at the cost of complexity) you could interlock with the throttle lever so that you can't flip the cutoff if the lever isn't at idle
More complexity also means more failure modes. You don't want it to be impossible to shut down the engines due to a broken throttle sensor.
This is not what happened here at all. The actions needed to activate the fuel cutoff switches are not similar to any other action a pilot would want to make during takeoff.
This is obviously an overstatement. Any two regularly performed actions can be confused. Sometimes (when tired or distracted) I've walked into my bathroom intending to shave, but mistakenly brushed my teeth and left. My toothbrush and razor are not similar in function or placement.
(I'm not strongly arguing against the murder scenario, just against the idea that it's impossible for it to be the confusion scenario.)
https://www.aerosimsolutions.com.au/custom-products/olympus-...
This would be like opening your car door when you meant to activate the turn signal.
The other poster's correction: "it’s like brushing your teeth with razor" is apt. Touching the fuel cutoff switches is not part of any procedure remotely relevant to the takeoff, so there's no trigger present that would prompt the automatic behavior.
More relevantly, you seem to me to be unduly confident about what this pilot's associative triggers might and might not be.
His statement was about a certain, obviously real tendency in general, existence of which is reasonable to assume there is enough research about.
He objected not to the unlikelihood of an accidental manipulation, but to the potential flaw in your comparison (which was at best a valid opinion).
https://www.google.com/search?q=%22Your+opinion+is+valid+but...
I think you're misarticulating my argument.
Test your mental model against the real world. This is your opportunity.
Same goes for accidental acceleration instead of braking. Two of the same kind of lever right next to each other.
Accidental acceleration while intending to turn on the wipers would be a fitting example, I don't think that happens though.
Think of the action as a stored function. Maybe they’ve always recalled the function as part of a certain list. It can be a case where the lists get confused rather than the modality of input (lever etc)
Probably more training required to bake a cake than drive a car (hours wise).
If we had your typical driver fly a plane we'd be doomed to a lot of crashes.
Weird mistakes can happen.
My partner got a good laugh out of it
The short answer is that they are _very_ different controls, that looks and operate in a completely different way, located in a different place, and it's completely unrealistic to think a pilot could have mistaken one for the other.
Different controls with different t shapes, operated in different ways, of different number, different size, and very different positions. One is down almost on the floor, and well rearward, the other is at stomach height and well forward.
The fuel cutoffs also require pulling the control out and over a guard.
If not there should be one as even my simple home wifi camera can record hours of hd video on the small sd card. And If there is, wouldn't that help to instantly identify such things?
I don’t think video is a bad idea. I assume there is a reason why it wasn’t done. Data wise black boxes actually store very little data (maybe a 100mbs), I don’t know if that is due to how old they are, or the requirements of withstanding extremes.
Heck they can make a back up directly to the cloud in addition to black box considering I'm able to watch YouTube in some flights nowadays.
(Most media outlets also got this wrong and were slow to make corrections. )
Rather, it uses a EAFR (Enhanced airborne flight recorder) which basically combines the functions. They’re also more advanced than older systems and can record for longer. The 787 has two of them - the forward one has its own power supply too.
There should be video as well, but I’m not sure what was recovered. Not necessarily part of the flight data recording, but there are other video systems.
https://www.geaerospace.com/sites/default/files/enhanced-air...
I'm not in aviation. But my between-the-lines straightforward reading is that unions see it as something with downsides (legal liability) but not much upside. It could be that there are a million tiny regulations that are known by everyone to be nonsensical, perhaps contradictory or just not in line with reality and it's basically impossible to be impeccably perfect if HD high fps video observation is done on them 24/7. Think about your own job and your boss's job or your home renovation work etc.
Theoretically they could say, ok, but the footage can only be used in case the plane crashes or something serious happens. Can't use it to detect minor deviations in the tiniest details. But we know that once the camera is there, there will be a push to scrutinize it all the time for everything. Next time there will be AI monitoring systems that check for alertness. Next time it will be checking for "psychological issues". Next time they will record and store it all and then when something happens, they will in hindsight point out some moment and sue the airline for not detecting that psychological cue and ban the pilot. It's a mess. If there's no footage, there's no such mess.
The truth is, you can't bring down the danger from human factors to absolute zero. It's exceedingly rare to have sabotage. In every human interaction, this can happen. The answer cannot be 24/7 full-blown totalitarian surveillance state on everyone. You'd have to prove that the danger from pilot is bigger than from any other occupation group. Should we also put bodycam on all medical doctors and record all surgeries and all interactions? It would help with malpractice cases. How about all teachers in school? To prevent child abuse. Etc. Etc.
Regulation is always in balance and in context of evidence possibilities and jurisprudence "reasonableness". If the interpretation is always to the letter and there is perfect surveillance, you need to adjust the rules to be actually realistic. If observation is hard and courts use common sense, rules can be more strict and stupid because "it looks good on paper".
You also have to think about potential abuses of footage. It would be an avenue for aircraft manufacturers, airlines, FAA, etc to push more blame on the pilots, because their side becomes more provable but the manufacturing side is not as much. You could then mandate camera video evidence for every maintenance task like with door plugs.
I wonder how the introduction of police body cam footage changed regulations of how police has to act. Along the lines of "hm, stuff on this footage is technically illegal but is clearly necessary, let's update the rules".
Additionally, footage could be encrypted with the NTSB having the keys.
Or simply make it a crime to use the footage in non-accident situations (this should be applied to other forms of surveillance, too ...).
Hopefully other countries will start deploying recording systems or start forcing manufacturers of planes to have these integrated into cockpits.
Surveillance is actually pretty common in many high-risk environments. And piloting is very much not just any other job but an exceedingly rare situation where the lives of hundreds of people are in the hands of only two people without anyone else being able to do anything to influence the outcome.
That pilot unions don't want surveillance is to be expected (the union is there to act in the pilots interest) but ultimately it isn't just up to them.
> Should we also put bodycam on all medical doctors and record all surgeries and all interactions?
Yes. We are finally starting to do so for police. These are all situations where an individual or very small team has direct control over the life of others who can't defend themselves.
In fact, you could add some AI to it, even, as an embedded system with a decent GPU can be bought for under $2000. It could help prevent issues from happening in the first place. Of course airgapped from the actual control system. But an AI can be very helpful in detecting and diagnosing problems.
It's very hard to solve one problem without creating another. At some point, you just gotta trust the pilot.
MCAS was basically made to prevent user input that would send the plane into a dangerous angle. The computer overrode the inputs. So there’s precedent for something like it.
This is incorrect. The manual stabilizer trim thumb switches override MCAS.
MCAS affects the stabilizer, the thumb switches affect the stabilizer, the cutoff switch affects the stabilizer.
The elevators are controlled by the control column and the autopilot.
> The trim switches override MCAS, but when released, MCAS can resume trimming down again.
That is correct. That is why the procedure is to return the trim to normal with the thumb switches, then turn off the trim system. That's it. That's all there is to it.
> but they can make the controls so heavy that it's impossible to pull up.
Almost right - the trim has more authority than the elevators. The trim's ability to travel far is to provide great ability to get out of trouble. I don't really know what factors the aerodynamics guys used to calculate the max travel required. I do know there is a travel limiter on it (as I worked on that, too!) which reduces the max travel at higher speeds, because otherwise it can rip the tail section off, which is a big no-no.
There are sooo many constraints on the design of an airplane I sometimes wonder how anyone manages to make one that works at all. The Wright Bros calculated that their machine would fly, and it did, barely. Their contemporaries did seat of the pants design, which is why they failed.
The Wright brothers succeeded because they were pioneers in wind tunnels and aluminum engine blocks.
The Wrights did a lot more than that to be successful. Their innovations were:
1. using a wind tunnel to correctly get lift and drag coefficients for various wing sections (as you wrote)
2. first aviation engine (high power/weight ratio) (as you wrote)
3. first propeller theory, enabling 90% efficiency (other aviation propellers were 50% efficient)
4. first 3-axis control system
5. identified and solved adverse yaw problem
6. first research and development program, where problems were identified in advance, and a machine was developed to solve each problem, then the solutions were put together to make the 1903 Wright Flyer
7. kept meticulous notes on all their work and preserved the evidence of their success, such as photographs and notebooks. Exacting replicas have been built, and their flight characteristics match the Wright's results
Thank you, I'll update my brain and future explanations. :)
Additionally, the stab trim cutoff switch overrode both MCAS and the thumb switches.
Using both easily and successfully averts MCAS crashes, as proven in the first incident (there were three, but only two are reported on).
I just remember that it happened commonly enough to US pilots. American pilots always recovered quickly enough that it didn't make the news before the fatal crashes.
https://www.nytimes.com/2019/09/18/magazine/boeing-737-max-c...
which has detailed information, but I don't trust the NYT. The article also erroneously reports that the MCAS trim rate is twice the speed of manual trim. The trim rate for both is 0.27 degrees per second.
That MCAS system?
Not so much on a Boeing.
not all my passwords are up and to the left, some are down and to the right, but when i type the wrong one into the wrong place, i type it accurately, i'm just not supposed to be typing it.
"time to do that thing i've practiced, reach to the left". shuts two engines off by muscle memory.
I remember once writing a cheat sheet for the commands by looking at what my fingers were doing.
If that were true, pilots would perform arbitrary motions all the time. Same with car drivers.
Typing something on a keyboard, especially when it's always in the same context, is always essentially the same physical action. The context of a password prompt is the same, the letters on the keyboard feel the same and are right next to each other.
Not comparable to pressing two very different buttons placed far apart, in a context when you'd never ever reach for them.
The only difference here is that the consequences are death instead of mere head shaking.
Murder needs more proof than just performing the wrong action. Until then we should apply Hanlon's Razor.
The mistake equivalent to what the pilot supposedly did would be if the pianist accidentally stuck a finger up his nose instead of playing the notes or something.
The cutoff switches are operated every flight so the muscle memory is there, ready to be triggered at the wrong time.
All we know is that something went wrong in the pilot's head in at least a single moment that caused him to perform a ground action during takeoff.
Depressive murder-suicide is one possible explanation. Altered mental state is another: insomnia, illness, drugs/medications could all explain an extreme brain fart. Perhaps he just had food poisoning? It's India after all.
Muscle memory allows you to perform both actions effectively but doesn't make you confuse them. Especially when the corresponding sequence of callouts and actions is practiced and repeated over and over.
All of us have muscle memory for activating the left blinker in our car and pulling the handbrake, but has anyone pulled the handbrake when they wanted to signal left?
Instead, it's that because muscle memory allows you to do things without thinking about it, you can get mixed up about which action you meant to perform and go through the whole process without realizing it.
ETA: downthread it is mentioned that these switches are used on the ground to cut the engines