15 ms·

> The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff s

> The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off. So the fuel supply was cut off intentionally. The switches in question are also built so they cannot be triggered accidentally, they need to be unlocked first by pulling them out. > In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so. And both pilots deny doing it. It's difficult to conclude anything other than murder-suicide.

ls-a 1y ago
So you're telling me that those switches don't have a voice that says "fuel cutoff switches transitioned" like in the movies? That's bad design
- yallpendantools 1y ago
  I know this thread runs the gamut of armchair experts, pretend experts, and actual experts and there's no telling who is which but I really want to know why the downvotes and why this is not a good idea. The idea is to notify for crucial settings, replace vocal confirmation (probably) already in the SOP anyway, reducing mistakes in bad faith or otherwise. Don't some planes already have an automated announcement for seatbelts on? Only reason I can think of why it's not there yet is the cost (whether $$$ or design opportunity) of cramming that in the already-cramped cockpit.
  - Mawr 1y ago
    My first instinct is that the suggestion is overfitted due to hinsight bias. This particular accident happened to involve these particular switches so let's add a warning to these switches. Duh! Some problems that immediately come to mind: - For which settings is there going to be a voice confirmation? Is their confirmation more important than all the other audio warnings? - During emergency situations, when pilot workload is high, will these only add to that workload, making the emergency even worse? - Will the pilots get so used to hearing these every day that their brains will simply tune them out as background noise? Really though, if a pilot wishes to doom an aircraft, there's 1000 different ways they could do so. The solution to this problem likely lies in the pilot mental health management department, rather than the fuel cut off switch audio warning one.
  - ufmace 1y ago
    Pretty obviously a bad joke and a bad idea IMO. I did not personally downvote, but I think it deserves its current score. Look at the timeline of the events. The switches were shut off, noticed to be shut off, and restored to the proper position within 10 seconds with the current system. Insufficient notification that the switches have been turned off was clearly not a problem in need of a solution. It would be slower and more challenging to understand an automated verbal announcement than the surely extremely obvious sudden lack of thrust and all engine dials rapidly dropping to zero. So it wouldn't contribute at all to solving this particular case, would only be a slightly annoying distraction in the more normal case of normal aircraft shut-down after completing its flights, and would be a potentially hazardous distraction in the intended emergency case of engine is on fire and fuel must be cut off immediately, where there's probably a bunch of other extremely important and urgent things to pay attention to and do other than a silly automated warning telling you what you just did.
    - ls-a 1y ago
      It's a joke about the design of safety systems involving actual human lives (movies being more safe). I get an audible warning on my laptop if i hit a key for too long for God's sake. These companies are a joke.
- yard2010 1y ago
  WHOOP WHOOP TERRAIN, TERRAIN! PULL UP! PULL UP! (WHOOP WHOOP)
  - ls-a 1y ago
    Wait till the final report is out and what resolution they come up with then we'll see who the joke is on
groos 1y ago
Suicide is quite a stretch without any supporting evidence from the pilots' backgrounds. I would take mental fog, cognitive overload, wrong muscle memory, even a defective fuel cutoff system over suicide.
- JSteph22 1y ago
  >mental fog, cognitive overload, wrong muscle memor Agreed. The sequence of events also supports this. I believe one of the pilots made a terrible muscle memory mistake and cutoff the fuel instead of raising the landing gear. This would explain why the landing gear was never raised, why the pilot who was accused of cutting off the fuel denied it (in his mind he had only retracted the landing gear) and why the engines were turned back on after presumably realizing the mistake.
  - shawabawa3 1y ago
    This also makes sense with why nobody on the recording mentions re engaging the fuel switches The pilot denies shutting off the fuel, then realises he'd done it accidentally and quietly reenables them hoping there's enough time to save them
  - cypherpunks01 1y ago
    Were the landing gear switches and fuel cutoff switches pretty close to each other here?
    - raphman 1y ago
      Not really. Landing gear switches are above the throttle between the screens¹, fuel cutoff switches are below it². ¹) https://youtu.be/RbmFmWqqq0c?t=19 https://youtu.be/RbmFmWqqq0c?t=19 ²) https://youtu.be/33hG9-BCJVQ?t=5 https://youtu.be/33hG9-BCJVQ?t=5 (I'm not an expert, I just watched these videos)
prepend 1y ago
I once worked with a software engineer who would do things and then bald face lie about it. This reminds me of that person. Me: “The build is breaking right after you checked in. Why did you do that?” Him:”I did not do so.” Me: “The commit shows it as you. And when I rolled back everything builds.” Him:”It must have been someone else.” That person was really annoying.
- Aurornis 1y ago
  I’ve worked with some chronic liars. They would deny reality no matter how much evidence you had. The weirdest thing was how often it worked for them. In each case their lying eventually caught up with them, but in some cases they’d get away with lying for years. It’s amazing how often someone would have clear evidence against what they were saying, but the people in positions of authority just wanted to de-escalate the situation and move on. They could turn anything into an ambiguous he-said she-said situation, possibly make a scene, and then make everyone so tired of the drama that they just wanted to move on.
  - ionwake 1y ago
    i worked in many companies but I always remember one , where during a public chat in the middle of an open office the programmer next to me (who was always conniving but I just ignored it ), said incorrectly something akin to " yes I know all about that source control its... based on locking " , the whole point was that although locking technically occurs, the SC would allow different coders to work on it at the same time. The non technical manager said correctly, "no the whole point is that the codebase isnt locked", to which the programmer replied " yeah thats what I mean". In that moment I realised he was just bare faced lying right infront of everyone, about a technical subject, only HE should be the expert in, and to this day I am perplexed why his contract kept being renewed. Eventually I was let go ( he possibly suggested I be let go ) for an incident that was unrelated to me. This is all fine, but i learnt 5 years on he was still being paid a top 1% salary at the same company. I promise the point isnt that I am jealous, its that this guy, who was a sub par coder and liar, somehow managed to keep his job whilst everyone else lost theirs and earnt untold amount in England ( where salaries are always low). My goodness - I just remembered he was found by police driving a vehicle seemingly under the influence on a motorway, work found out after the police called them, and somehow he turned up the next day at work , lied about it, and STILL kept his job. I am only mentioning this guy , because he was NOT a nepotist hire, he was just some guy who would lie and somehow people were ok with it. I still think of him often and wish I could have learnt more from his abilities just out of interest.
WalterBright 1y ago
> It's difficult to conclude anything other than murder-suicide. Remember that incident where a cop pulled out his taser and tased the suspect? Except he pulled out his pistol and fired it. The taser looks nothing like a pistol, feels nothing like it, yet it is still possible to confuse the two in the heat of the moment.
- throwawaycan 1y ago
  It’s always easy in those threads to see who’s familiar with the world of aviation and who’s not. No it’s not comparable to a cop that confuses things in the heat of the moment. Not anywhere close to be relatable. If it was, planes would be crashing down the sky quite often (and it would have been fixed for decades already).
  - octo888 1y ago
    WalterBright is not totally unfamiliar with the aviation world...: > Bright is the son of the United States Air Force pilot Charles D. Bright > Bright graduated from Caltech in 1979 with a Bachelor of Science in Mechanical Engineering and a minor in Aeronautical Engineering > He worked for Boeing for 3 years on the development of the 757 stabilizer trim system
    - nosianu 1y ago
      So? The comparison still makes no sense. Those switches cannot be accidentally flipped, and they are in a place where the pilots' hands have no action to take at all during that period. That is very different from mixing up two similar weapons in a similar location. Location of the switches: https://media.cnn.com/api/v1/images/stellar/prod/c-gettyimages-951922648-20250711223914009.jpg https://media.cnn.com/api/v1/images/stellar/prod/c-gettyimag... Here is a video of a takeoff and climb in a 787: https://youtu.be/TTZozTaWiRo https://youtu.be/TTZozTaWiRo The pilots have no business with their hands in the area of those switches in that phase of the flight (9:30+ in the video). They don't even have to touch the throttle, and even if they did, that's a long way from where you touch the throttle down to the base where those switches are. Which you can't just flip either. How is that even remotely similar to that cop's situation?
YetAnotherNick 1y ago
Reminds me of 2017 Las Vegas shooting. The perpetrator looked and acted completely normal till the day of shooting and all his issues like anxiety or losing money was nothing far from ordinary. And what seems all of a sudden did a well planned shooting and didn't bother to leave a note or tell his story.
- refulgentis 1y ago
  Free memento mori: you're both free-associating. There's 0 reason to conclude murder-suicide, there's an infinitude of things that could have the same result, and both pilots denied it to eachother: how is that presented as proof? I hope I don't need to explain why the fact no one knew in advance the Las Vegas shooter was going to shoot has ~0 similarities with the situation as we know it, and banal similarities with every murder.
  - Aeolun 1y ago
    Using that reasoning all airplane crashes have a lot in common too. Doesn’t mean the ones where you cannot determine the reason and have to speculate don’t suck.
    - refulgentis 1y ago
      Could you explain more? There's too many negatives in that last sentence for my decaffeinated early morning brain. I'm titillated by the idea there's a way to justify making up things so I really want to parse it.
      - Aeolun 1y ago
        It means, sometimes the best you will get is speculation, because there’s no definite answers to be had. E.g. it’d be nice if just hearing the CVR meant you knew the exact cause. Unfortunately not the case here.
burnt-resistor 1y ago
> It's difficult to conclude anything other than murder-suicide. You're leaping into the minds of others and drawing conclusions of their intent. One of them moved the levers. It could've been an unplanned reaction, a terrible mistake, or it could've been intentional. We may never know the intention even with a comprehensive and complete investigation. To claim otherwise is arrogance.
- epolanski 1y ago
  The car equivalent is being on a highway and "mistakenly" pulling the hand brakes, except that there are 2 hand brakes and you need to first unlock both of them. That's very hard to do by panic and mistake, if not impossible by design.
  - burnt-resistor 1y ago
    Bad analogy because pilots are trained and rehearse and practice memory items until they are instinctual. > impossible by design. Deflecting that the human is the weakest part of the system. One or other may have panicked and made a mistake, made a mistake unintentionally, went crazy and doomed the flight, or intentionally doomed the flight for some socioeconomic reasons. These are speculative possibilities that we don't know yet, and may never know; we only know what has definitely happened from the evidence per the investigation. It's standing way out over one's feet to declare from an armchair that it was "definitely" X or Y before the investigation is complete.
    - epolanski 1y ago
      Forget my words then and take those from aviation experts. The fact that a pilot would cut off fuel from both engines, in sequence while taking off is virtually impossible to happen unless deliberate. Hence the hand brake comparison, it does not come natural to use it while driving.
      - burnt-resistor 1y ago
        It was done. Yes. There is no way to determine from the evidence why it was done, how much conscious or not thought was put into it, or the thought process behind it.
ExoticPearTree 1y ago
> And both pilots deny doing it. > It's difficult to conclude anything other than murder-suicide. You’re trying to prove a negative here. I am not familiar with the 787 operations, but there are a few issues that need to be sorted out first: - altitude when pilots start the after takeoff checklist - if there are any other switches that are operated in tandem in the general vicinity of where the engine cutoff switches are - if the cutoff switches had the locking mechanisms present, and if not, if they could be moved inadvertently by the pilot flying hand Discarding other possibilities in an investigation can have adverse consequences. Did you ever always push the right buttons every time?
- decimalenough 1y ago
  The switches have lockout mechanisms that prevent accidental triggering. I'm not a pilot, but these guys are, and they find it exceedingly unlikely that anyone would switch both off by accident: https://www.youtube.com/live/SE0BetkXsLg?feature=shared https://www.youtube.com/live/SE0BetkXsLg?feature=shared
  - ExoticPearTree 1y ago
    You have to time it spy movie right to ensure dying. This is what I am debating. There are too many variables you need to account for. For example, I want an expert opinion about the tone in the cockpit when the other pilot said “No, I did not touch it” or what was said. Is it calm? Surprised? Cold?
- Aeolun 1y ago
  > Did you ever always push the right buttons every time? A whole world full of 787’s is pushing the right buttons every single day. If we’re talking about accidentally pressing buttons it seems we’d have seen incidents before.
  - ExoticPearTree 1y ago
    > If we’re talking about accidentally pressing buttons it seems we’d have seen incidents before. Well, of course I talk about an accidental touch of the wrong buttons. Flying is very safe, but at the same time, you will never know how many near misses happen daily that don't become accidents.
ssivark 1y ago
> So the fuel supply was cut off intentionally. The switches in question are also built so they cannot be triggered accidentally FAA issued a Special Airworthiness Information Bulletin SAIB NM-18-33 in 2018 warning that on several Boeing models including the 787 the locking mechanism of the fuel switches could be inoperative. https://www.aviacionline.com/recommended-versus-mandatory-the-potential-link-between-an-faa-bulletin-and-the-air-india-disaster https://www.aviacionline.com/recommended-versus-mandatory-th... Per FAA the checks were recommended but not mandatory.
moralestapia 1y ago
>It's difficult to conclude anything other than murder-suicide. This kind of attitude gets innocent people behind bars for life. Disgusting. It's difficult to conclude anything until the investigation is finished and I hope the ones who are carrying it out are as levelheaded, neutral and professional as possible.
michaelmrose 1y ago
Given the recent boundless incompetence by Boeing why not ask if their is any way for such to fail out of scope of the normal interface?
card_zero 1y ago
Cutting the engines within seconds of leaving the ground doesn't fit suicide very well. I'd expect something more like flying into the side of a mountain or heading really far out into the Indian ocean until you vanish from radar and cause a big mystery. For instance, you might deliberately kill yourself by driving your car really fast into something solid, but you probably wouldn't try to do that while backing out of the garage.
- coolspot 1y ago
  I think it is opposite. Flying into a mountain & etc would require one pilot to somehow incapacitate another pilot. Cutting fuel off, if done on takeoff, is not recoverable (engines can’t relight and spin up quickly enough).
  - card_zero 1y ago
    OK, that makes a kind of sense, altitude would spoil the plan, if a suicidal pilot's only plan was to cut the engines.
- userbinator 1y ago
  See Germanwings 9525 for an example of a conclusive suicide with no doubt from all the evidence.
  - card_zero 1y ago
    See me obliquely referencing that with "flying into the side of a mountain".
Velorivox 1y ago
This is highly reminiscent to me of this case. [0] The co-pilot accidentally hit the wrong switch and then quietly corrected his mistake later, without resetting the previous switch (which led to feathering). [0] https://en.wikipedia.org/wiki/Yeti_Airlines_Flight_691 https://en.wikipedia.org/wiki/Yeti_Airlines_Flight_691
- deleted 1y ago
  [deleted]
i_have_to_speak 1y ago
[flagged]
procaryote 1y ago
It's interesting to see how people manage incomplete information. You could have made the same assumptions after the first MCAS crash, much like boeing assumed pilot error. It's easy, comforting and sometimes kills people because it makes you stop looking.
Simon_O_Rourke 1y ago
> It's difficult to conclude anything other than murder-suicide. The balance of probability might tend to support that hypothesis. However I'm wondering if it was just something involuntary. My ex for instance who learned to drive on a stick shift would randomly stall the engine after a few weeks driving an automatic.
chupchap 1y ago
Or a mechanical failure
- Spooky23 1y ago
  Serious question: why is it so difficult to fathom that a deranged pilot could decide to commit suicide by plane?
  - shash 1y ago
    Not difficult, but can you close an investigation on that note without going over other possibilities? What if there's another safety lesson to be learnt here?
    - Spooky23 1y ago
      The investigation isn’t closed. A preliminary report is usually required to be released within a few weeks of an incident.
  - ExoticPearTree 1y ago
    To answer your question: because it is a very rare occurence.
    - cjbprime 1y ago
      It's not that rare, and there are institutional factors (such as seeking treatment for psychosis being career-ending for a pilot) that incentivize serious pilot mental health crises being untreated.
    - BurningFrog 1y ago
      All commercial plane crashes are very rare occurrences.
- ceejayoz 1y ago
  Both switches, at slightly different times? Seems pretty unlikely.
ceejayoz 1y ago
> The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off. > As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. Damn. That's pretty quick to diagnose and take action. Boeing's probably gonna have a big sigh of relief over this one.
- Aeolun 1y ago
  > Damn. That's pretty quick to diagnose and take action. I have to imagine that “You are flying” and “You just cut off all fuel to the engines” must generate a pretty obvious claxon of warnings.
- dehrmann 1y ago
  > Boeing's probably gonna have a big sigh of relief over this one. The 787 is 15 years old, and this particular plane was 10 years old. It always seemed unlikely to be a major, new issue. My money was actually on maintenance.
  - sofixa 1y ago
    While unlikely, there have been issues before that took decades to surface (e.g. Aloha Airlines where a 737 manufactured more than a decade earlier became a cabriolet due to Boeing underestimating sea water corrosion and short flight cycles), or the 737 rudder issues where the planes were also 10+ years old.
alephnerd 1y ago
> It's difficult to conclude anything other than murder-suicide. Is it possible it could have been an accident or a mistake by one of the pilots? How intention-proofed are engine cutoffs?
- ummonk 1y ago
  You have to pull the switches out (against a spring) to be able to move them over a notch and flip them. Not really something you can just mistake for another switch or bump into by accident. I'd liken it to turning off the ignition by turning the key while driving your car. Possibly something that could happen if you're really fatigued, but requires quite a mental lapse.
  - magicalhippo 1y ago
    Is it possible to rest the switch on the notch? Does the switch make contact if the switch is in the RUN position but the switch is not completely down? That is, is it possible they flipped the switches over to RUN but did not seat the switches properly, and instead leaving them on top of the notch, with later vibration causing the switches to disengage? Just trying to think of some semi-plausible non-active causes.
  - deleted 1y ago
    [deleted]
  - joezydeco 1y ago
    Report says the switches went to cutoff one second apart from each other. Can a human do the physical operation on two switches that quickly?
    - snypher 1y ago
      There's a good photo of them here; https://theaircurrent.com/aviation-safety/ai171-investigation-fuel-control-switches/ https://theaircurrent.com/aviation-safety/ai171-investigatio... You can do them both with one hand.
lazystar 1y ago
https://ad.easa.europa.eu/ad/NM-18-33 https://ad.easa.europa.eu/ad/NM-18-33 well hold your horses there... from the FAA in their 2019 report linked above: > The Boeing Company (Boeing) received reports from operators of Model 737 airplanes that the fuel control switches were installed with the locking feature disengaged. The fuel control switches (or engine start switches) are installed on the control stand in the flight deck and used by the pilot to supply or cutoff fuel to the engines. The fuel control switch has a locking feature to prevent inadvertent operation that could result in unintended switch movement between the fuel supply and fuel cutoff positions. In order to move the switch from one position to the other under the condition where the locking feature is engaged, it is necessary for the pilot to lift the switch up while transitioning the switch position. If the locking feature is disengaged, the switch can be moved between the two positions without lifting the switch during transition, and the switch would be exposed to the potential of inadvertent operation. Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown. Boeing informed the FAA that the fuel control switch design, including the locking feature, is similar on various Boeing airplane models. The table below identifies the affected airplane models and related part numbers (P/Ns) of the fuel control switch, which is manufactured by Honeywell. > If the locking feature is disengaged, the switch can be moved between the two positions without lifting the switch during transition, and the switch would be exposed to the potential of inadvertent operation. Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown
- noduerme 1y ago
  What is "01 second" as quoted above? If it's 1 second, you could possibly conclude that it was intentional. If it's 0.1 second you might think it was an accident and the lock was disengaged.
  - JumpCrisscross 1y ago
    One second. (Runway four is frequently zero four because radios.)
    - deleted 1y ago
ummonk 1y ago
Yeah and the other pilot flipped the switches back on and one of the engines started spooling up but it was too late. Murder-suicide looks like the likely conclusion, given that flipping the cutoff switches requires a very deliberate action. That said, it's not entirely impossible that due to stress or fatigue the pilot had some kind of mental lapse and post-flight muscle memory (of shutting off the engines) kicked in when the aircraft lifted off.
- gosub100 1y ago
  > Murder-suicide looks like the likely conclusion But why cutoff the fuel instead of flying into terrain? It's such a passive action
  - lotsofpulp 1y ago
    I imagine it would be more difficult to fly into terrain without a cooperative co pilot than cutting the fuel just after take off.
  - ummonk 1y ago
    For whatever reason, the Egypt Air 990 pilot initiated his murder-suicide by pulling the thrust to idle and then flipping the fuel cutoff switches.
- breadwinner 1y ago
  > post-flight muscle memory (of shutting off the engines) kicked in Possible, and if so it is too early to conclude it was murder-suicide. See also: https://www.thehindu.com/news/national/dgca-slaps-80-lakh-fine-on-air-india-for-overworking-pilots/article67981033.ece https://www.thehindu.com/news/national/dgca-slaps-80-lakh-fi...
  - Jtsummers 1y ago
    The report shows 0 flight hours during the prior 24 hours for both pilots, and 7 hours and 6 hours each for the previous 7 days. It seems they were both fresh pilots for this flight.
bgwalter 1y ago
Does the Flight Data Recorder consider the physical position of the fuel switches or does it get the information from some fly-by-wire part that could be buggy? The conversation would suggest that the switches were in CUTOFF position, but there is also a display that summarizes the engine status. There is no conversation that mentions flipping the switch to RUN again. EDIT: Why is there no Cockpit Video Recorder? The days of limited storage are over.
- WalterBright 1y ago
  I've had discussions on HN with people who insisted that having a video camera always pointed out the control tower at the runway was some sort of impossibility. Despite every 7-11 having such a system. This would leave accident investigators with a lot of work to do to try to figure out how a collision happened.
- tekla 1y ago
  Yes there is.
- deleted 1y ago
  [deleted]
- ssl232 1y ago
  > EDIT: Why is there no Cockpit Video Recorder? The days of limited storage are over. Pilots unions are dead against it.
  - ekianjo 1y ago
    And Pilots end up dead because of it.
  - bombcar 1y ago
    And now some pilots are dead. Just allow cockpit video recorders, and if they're ever used for anything, the pilots (or their heirs) get $250k in cash.
  - gnulinux996 1y ago
dcreater 1y ago
Do you know if the mechanical position of the switch guarantees its electronic state without any possibility for hardware malfunction? If no, then you are claiming a person made one of the most grave acts of inhumanity ever. This sounds to me like an electronics issue - an intermittent, inadvertent state transition likely due to some PCB component malfunction
- cosmicgadget 1y ago
  Murder-suicide has happened on a few occasions. How many times has your malfunction occurred on an aircraft fuel system?
  - bgwalter 1y ago
    Not precisely the electrical malfunction, but dual engine shutdown has occurred, fortunately after landing: https://www.aerosociety.com/news/ana-787-engine-shutdown/ https://www.aerosociety.com/news/ana-787-engine-shutdown/
    - shash 1y ago
      Different engine (those are Trents and this was a GEnx), but yeah, that _did_ happen.
    - cosmicgadget 1y ago
      That doesn't seem to be a malfunction at all.
- stefan_ 1y ago
  And then 10s later the switches magically fixed themselves? The likely not electronically connected switches since that would compromise engine redundancy?
  - ekianjo 1y ago
    The rodents were remorseful and fixed the cables in the meantime. /s
__turbobrew__ 1y ago
I wonder if the switches are still in tact after the crash? Can they verify that the switches are mechanically sound? If so, seems highly likely it was intentional.
- userbinator 1y ago
  I'd suspect the wiring leading from the switches to the engine controllers first, especially since it looked like both circuits cut out nearly at the same time.
  - shash 1y ago
    This is speculation again since I don't really know, but my understanding of aviation engineering is that there would be two separate controllers for each engine connected to these two switches. At no point would they be connected to the _same_ control unit. The really short time (~1s) between the two being cutoff is the difficult thing to explain here.
    - userbinator 1y ago
      Are the wires leading up to those switches on the console also kept separate, or are they just bundled together as part of the same harness (presumably before it splits to go to the engines)? I think that's also important in understanding the possible failure modes.
- pigbearpig 1y ago
  There are pictures of them in the report.
- deleted 1y ago
  [deleted]
Waterluvian 1y ago
Not that humans are known to behave rationally when trying to commit suicide, but it’s interesting that the switches were re-engaged successfully without protest or a fight. It’s just an interesting detail to wonder about.
- yardstick 1y ago
  The reasoning I’ve heard is: it didn’t matter anymore, the damage was already done and there was no way any attempts at recovering from it would have been successful.
  - ExoticPearTree 1y ago
    There would have been an inaction on the part of the pilot that did this, but it is not mentioned in the CVR transcript. Hard to believe the other pilot wouldn’t have said anything. Recovering the airplane and have some people survive the crash are two very different things.
userbinator 1y ago
and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec Or more precisely, the signals which come from them were found to behave as such. Without any audible record of turning the switches off, I wouldn't blame the pilots without first checking the wiring and switches themselves for faults. This reminds me of the glitches caused by tin whiskers.
- crtified 1y ago
  I agree, there's a significant distinction between "the switches were (physically) flipped" and "the circuit was opened/closed". In this case, it may be a moot distinction, particularly if no physical evidence of fault or tampering has been discovered in investigation. But, in theory, very important - there's a lot of potential grey-area between the two statements. The proximity of the incident to the ground may also increase the possible attack vectors for simple remote triggers.
  - shash 1y ago
    My understanding from what we've been reading is that these are physical switches that cannot be moved using remote triggers. Wildly speculating, there _may_ be a possibility that the _effect_ of the switch may be triggered remotely, if it's a signal being read by a control unit or computer of some sort that then actuates the specific electromechanical components. But it would seem impossible to move a physical switch to do it. As an analogy, if you have a smart lock, you can remotely trigger the _effect_ of turning the key using (let's say a bluetooth control), but if a key is inserted into the keyhole, unless there is two-way mechanical linkage, that key _will not turn_.
    - crtified 1y ago
      Any switch becomes irrelevant if a saboteur has access to the behind-the-panel wires that the switch operates. But I presume that would leave physical evidence which would have been discovered by now. Presume, but cannot be certain.
- 1y ago

ls-a 1y ago

So you're telling me that those switches don't have a voice that says "fuel cutoff switches transitioned" like in the movies? That's bad design

yallpendantools 1y ago
I know this thread runs the gamut of armchair experts, pretend experts, and actual experts and there's no telling who is which but I really want to know why the downvotes and why this is not a good idea. The idea is to notify for crucial settings, replace vocal confirmation (probably) already in the SOP anyway, reducing mistakes in bad faith or otherwise. Don't some planes already have an automated announcement for seatbelts on? Only reason I can think of why it's not there yet is the cost (whether $$$ or design opportunity) of cramming that in the already-cramped cockpit.
- Mawr 1y ago
  My first instinct is that the suggestion is overfitted due to hinsight bias. This particular accident happened to involve these particular switches so let's add a warning to these switches. Duh! Some problems that immediately come to mind: - For which settings is there going to be a voice confirmation? Is their confirmation more important than all the other audio warnings? - During emergency situations, when pilot workload is high, will these only add to that workload, making the emergency even worse? - Will the pilots get so used to hearing these every day that their brains will simply tune them out as background noise? Really though, if a pilot wishes to doom an aircraft, there's 1000 different ways they could do so. The solution to this problem likely lies in the pilot mental health management department, rather than the fuel cut off switch audio warning one.
- ufmace 1y ago
  Pretty obviously a bad joke and a bad idea IMO. I did not personally downvote, but I think it deserves its current score. Look at the timeline of the events. The switches were shut off, noticed to be shut off, and restored to the proper position within 10 seconds with the current system. Insufficient notification that the switches have been turned off was clearly not a problem in need of a solution. It would be slower and more challenging to understand an automated verbal announcement than the surely extremely obvious sudden lack of thrust and all engine dials rapidly dropping to zero. So it wouldn't contribute at all to solving this particular case, would only be a slightly annoying distraction in the more normal case of normal aircraft shut-down after completing its flights, and would be a potentially hazardous distraction in the intended emergency case of engine is on fire and fuel must be cut off immediately, where there's probably a bunch of other extremely important and urgent things to pay attention to and do other than a silly automated warning telling you what you just did.
  - ls-a 1y ago
    It's a joke about the design of safety systems involving actual human lives (movies being more safe). I get an audible warning on my laptop if i hit a key for too long for God's sake. These companies are a joke.
yard2010 1y ago
WHOOP WHOOP TERRAIN, TERRAIN! PULL UP! PULL UP! (WHOOP WHOOP)
- ls-a 1y ago
  Wait till the final report is out and what resolution they come up with then we'll see who the joke is on

groos 1y ago

Suicide is quite a stretch without any supporting evidence from the pilots' backgrounds. I would take mental fog, cognitive overload, wrong muscle memory, even a defective fuel cutoff system over suicide.

JSteph22 1y ago
>mental fog, cognitive overload, wrong muscle memor Agreed. The sequence of events also supports this. I believe one of the pilots made a terrible muscle memory mistake and cutoff the fuel instead of raising the landing gear. This would explain why the landing gear was never raised, why the pilot who was accused of cutting off the fuel denied it (in his mind he had only retracted the landing gear) and why the engines were turned back on after presumably realizing the mistake.
- shawabawa3 1y ago
  This also makes sense with why nobody on the recording mentions re engaging the fuel switches The pilot denies shutting off the fuel, then realises he'd done it accidentally and quietly reenables them hoping there's enough time to save them
- cypherpunks01 1y ago
  Were the landing gear switches and fuel cutoff switches pretty close to each other here?
  - raphman 1y ago
    Not really. Landing gear switches are above the throttle between the screens¹, fuel cutoff switches are below it². ¹) https://youtu.be/RbmFmWqqq0c?t=19 https://youtu.be/RbmFmWqqq0c?t=19 ²) https://youtu.be/33hG9-BCJVQ?t=5 https://youtu.be/33hG9-BCJVQ?t=5 (I'm not an expert, I just watched these videos)

prepend 1y ago

I once worked with a software engineer who would do things and then bald face lie about it. This reminds me of that person. Me: “The build is breaking right after you checked in. Why did you do that?” Him:”I did not do so.” Me: “The commit shows it as you. And when I rolled back everything builds.” Him:”It must have been someone else.” That person was really annoying.

Aurornis 1y ago
I’ve worked with some chronic liars. They would deny reality no matter how much evidence you had. The weirdest thing was how often it worked for them. In each case their lying eventually caught up with them, but in some cases they’d get away with lying for years. It’s amazing how often someone would have clear evidence against what they were saying, but the people in positions of authority just wanted to de-escalate the situation and move on. They could turn anything into an ambiguous he-said she-said situation, possibly make a scene, and then make everyone so tired of the drama that they just wanted to move on.
- ionwake 1y ago
  i worked in many companies but I always remember one , where during a public chat in the middle of an open office the programmer next to me (who was always conniving but I just ignored it ), said incorrectly something akin to " yes I know all about that source control its... based on locking " , the whole point was that although locking technically occurs, the SC would allow different coders to work on it at the same time. The non technical manager said correctly, "no the whole point is that the codebase isnt locked", to which the programmer replied " yeah thats what I mean". In that moment I realised he was just bare faced lying right infront of everyone, about a technical subject, only HE should be the expert in, and to this day I am perplexed why his contract kept being renewed. Eventually I was let go ( he possibly suggested I be let go ) for an incident that was unrelated to me. This is all fine, but i learnt 5 years on he was still being paid a top 1% salary at the same company. I promise the point isnt that I am jealous, its that this guy, who was a sub par coder and liar, somehow managed to keep his job whilst everyone else lost theirs and earnt untold amount in England ( where salaries are always low). My goodness - I just remembered he was found by police driving a vehicle seemingly under the influence on a motorway, work found out after the police called them, and somehow he turned up the next day at work , lied about it, and STILL kept his job. I am only mentioning this guy , because he was NOT a nepotist hire, he was just some guy who would lie and somehow people were ok with it. I still think of him often and wish I could have learnt more from his abilities just out of interest.

WalterBright 1y ago

> It's difficult to conclude anything other than murder-suicide. Remember that incident where a cop pulled out his taser and tased the suspect? Except he pulled out his pistol and fired it. The taser looks nothing like a pistol, feels nothing like it, yet it is still possible to confuse the two in the heat of the moment.

throwawaycan 1y ago
It’s always easy in those threads to see who’s familiar with the world of aviation and who’s not. No it’s not comparable to a cop that confuses things in the heat of the moment. Not anywhere close to be relatable. If it was, planes would be crashing down the sky quite often (and it would have been fixed for decades already).
- octo888 1y ago
  WalterBright is not totally unfamiliar with the aviation world...: > Bright is the son of the United States Air Force pilot Charles D. Bright > Bright graduated from Caltech in 1979 with a Bachelor of Science in Mechanical Engineering and a minor in Aeronautical Engineering > He worked for Boeing for 3 years on the development of the 757 stabilizer trim system
  - nosianu 1y ago
    So? The comparison still makes no sense. Those switches cannot be accidentally flipped, and they are in a place where the pilots' hands have no action to take at all during that period. That is very different from mixing up two similar weapons in a similar location. Location of the switches: https://media.cnn.com/api/v1/images/stellar/prod/c-gettyimages-951922648-20250711223914009.jpg https://media.cnn.com/api/v1/images/stellar/prod/c-gettyimag... Here is a video of a takeoff and climb in a 787: https://youtu.be/TTZozTaWiRo https://youtu.be/TTZozTaWiRo The pilots have no business with their hands in the area of those switches in that phase of the flight (9:30+ in the video). They don't even have to touch the throttle, and even if they did, that's a long way from where you touch the throttle down to the base where those switches are. Which you can't just flip either. How is that even remotely similar to that cop's situation?

YetAnotherNick 1y ago

Reminds me of 2017 Las Vegas shooting. The perpetrator looked and acted completely normal till the day of shooting and all his issues like anxiety or losing money was nothing far from ordinary. And what seems all of a sudden did a well planned shooting and didn't bother to leave a note or tell his story.

refulgentis 1y ago
Free memento mori: you're both free-associating. There's 0 reason to conclude murder-suicide, there's an infinitude of things that could have the same result, and both pilots denied it to eachother: how is that presented as proof? I hope I don't need to explain why the fact no one knew in advance the Las Vegas shooter was going to shoot has ~0 similarities with the situation as we know it, and banal similarities with every murder.
- Aeolun 1y ago
  Using that reasoning all airplane crashes have a lot in common too. Doesn’t mean the ones where you cannot determine the reason and have to speculate don’t suck.
  - refulgentis 1y ago
    Could you explain more? There's too many negatives in that last sentence for my decaffeinated early morning brain. I'm titillated by the idea there's a way to justify making up things so I really want to parse it.
    - Aeolun 1y ago
      It means, sometimes the best you will get is speculation, because there’s no definite answers to be had. E.g. it’d be nice if just hearing the CVR meant you knew the exact cause. Unfortunately not the case here.

burnt-resistor 1y ago

> It's difficult to conclude anything other than murder-suicide. You're leaping into the minds of others and drawing conclusions of their intent. One of them moved the levers. It could've been an unplanned reaction, a terrible mistake, or it could've been intentional. We may never know the intention even with a comprehensive and complete investigation. To claim otherwise is arrogance.

epolanski 1y ago
The car equivalent is being on a highway and "mistakenly" pulling the hand brakes, except that there are 2 hand brakes and you need to first unlock both of them. That's very hard to do by panic and mistake, if not impossible by design.
- burnt-resistor 1y ago
  Bad analogy because pilots are trained and rehearse and practice memory items until they are instinctual. > impossible by design. Deflecting that the human is the weakest part of the system. One or other may have panicked and made a mistake, made a mistake unintentionally, went crazy and doomed the flight, or intentionally doomed the flight for some socioeconomic reasons. These are speculative possibilities that we don't know yet, and may never know; we only know what has definitely happened from the evidence per the investigation. It's standing way out over one's feet to declare from an armchair that it was "definitely" X or Y before the investigation is complete.
  - epolanski 1y ago
    Forget my words then and take those from aviation experts. The fact that a pilot would cut off fuel from both engines, in sequence while taking off is virtually impossible to happen unless deliberate. Hence the hand brake comparison, it does not come natural to use it while driving.
    - burnt-resistor 1y ago
      It was done. Yes. There is no way to determine from the evidence why it was done, how much conscious or not thought was put into it, or the thought process behind it.

ExoticPearTree 1y ago

> And both pilots deny doing it. > It's difficult to conclude anything other than murder-suicide. You’re trying to prove a negative here. I am not familiar with the 787 operations, but there are a few issues that need to be sorted out first: - altitude when pilots start the after takeoff checklist - if there are any other switches that are operated in tandem in the general vicinity of where the engine cutoff switches are - if the cutoff switches had the locking mechanisms present, and if not, if they could be moved inadvertently by the pilot flying hand Discarding other possibilities in an investigation can have adverse consequences. Did you ever always push the right buttons every time?

decimalenough 1y ago
The switches have lockout mechanisms that prevent accidental triggering. I'm not a pilot, but these guys are, and they find it exceedingly unlikely that anyone would switch both off by accident: https://www.youtube.com/live/SE0BetkXsLg?feature=shared https://www.youtube.com/live/SE0BetkXsLg?feature=shared
- ExoticPearTree 1y ago
  You have to time it spy movie right to ensure dying. This is what I am debating. There are too many variables you need to account for. For example, I want an expert opinion about the tone in the cockpit when the other pilot said “No, I did not touch it” or what was said. Is it calm? Surprised? Cold?
Aeolun 1y ago
> Did you ever always push the right buttons every time? A whole world full of 787’s is pushing the right buttons every single day. If we’re talking about accidentally pressing buttons it seems we’d have seen incidents before.
- ExoticPearTree 1y ago
  > If we’re talking about accidentally pressing buttons it seems we’d have seen incidents before. Well, of course I talk about an accidental touch of the wrong buttons. Flying is very safe, but at the same time, you will never know how many near misses happen daily that don't become accidents.

ssivark 1y ago

> So the fuel supply was cut off intentionally. The switches in question are also built so they cannot be triggered accidentally FAA issued a Special Airworthiness Information Bulletin SAIB NM-18-33 in 2018 warning that on several Boeing models including the 787 the locking mechanism of the fuel switches could be inoperative. https://www.aviacionline.com/recommended-versus-mandatory-the-potential-link-between-an-faa-bulletin-and-the-air-india-disaster https://www.aviacionline.com/recommended-versus-mandatory-th... Per FAA the checks were recommended but not mandatory.

moralestapia 1y ago

>It's difficult to conclude anything other than murder-suicide. This kind of attitude gets innocent people behind bars for life. Disgusting. It's difficult to conclude anything until the investigation is finished and I hope the ones who are carrying it out are as levelheaded, neutral and professional as possible.

michaelmrose 1y ago

Given the recent boundless incompetence by Boeing why not ask if their is any way for such to fail out of scope of the normal interface?

card_zero 1y ago

Cutting the engines within seconds of leaving the ground doesn't fit suicide very well. I'd expect something more like flying into the side of a mountain or heading really far out into the Indian ocean until you vanish from radar and cause a big mystery. For instance, you might deliberately kill yourself by driving your car really fast into something solid, but you probably wouldn't try to do that while backing out of the garage.

coolspot 1y ago
I think it is opposite. Flying into a mountain & etc would require one pilot to somehow incapacitate another pilot. Cutting fuel off, if done on takeoff, is not recoverable (engines can’t relight and spin up quickly enough).
- card_zero 1y ago
  OK, that makes a kind of sense, altitude would spoil the plan, if a suicidal pilot's only plan was to cut the engines.
userbinator 1y ago
See Germanwings 9525 for an example of a conclusive suicide with no doubt from all the evidence.
- card_zero 1y ago
  See me obliquely referencing that with "flying into the side of a mountain".

Velorivox 1y ago

This is highly reminiscent to me of this case. [0] The co-pilot accidentally hit the wrong switch and then quietly corrected his mistake later, without resetting the previous switch (which led to feathering). [0] https://en.wikipedia.org/wiki/Yeti_Airlines_Flight_691 https://en.wikipedia.org/wiki/Yeti_Airlines_Flight_691

deleted 1y ago
[deleted]

i_have_to_speak 1y ago

[flagged]

procaryote 1y ago

It's interesting to see how people manage incomplete information. You could have made the same assumptions after the first MCAS crash, much like boeing assumed pilot error. It's easy, comforting and sometimes kills people because it makes you stop looking.

Simon_O_Rourke 1y ago

> It's difficult to conclude anything other than murder-suicide. The balance of probability might tend to support that hypothesis. However I'm wondering if it was just something involuntary. My ex for instance who learned to drive on a stick shift would randomly stall the engine after a few weeks driving an automatic.

chupchap 1y ago

Or a mechanical failure

Spooky23 1y ago
Serious question: why is it so difficult to fathom that a deranged pilot could decide to commit suicide by plane?
- shash 1y ago
  Not difficult, but can you close an investigation on that note without going over other possibilities? What if there's another safety lesson to be learnt here?
  - Spooky23 1y ago
    The investigation isn’t closed. A preliminary report is usually required to be released within a few weeks of an incident.
- ExoticPearTree 1y ago
  To answer your question: because it is a very rare occurence.
  - cjbprime 1y ago
    It's not that rare, and there are institutional factors (such as seeking treatment for psychosis being career-ending for a pilot) that incentivize serious pilot mental health crises being untreated.
  - BurningFrog 1y ago
    All commercial plane crashes are very rare occurrences.
ceejayoz 1y ago
Both switches, at slightly different times? Seems pretty unlikely.

ceejayoz 1y ago

> The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off. > As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. Damn. That's pretty quick to diagnose and take action. Boeing's probably gonna have a big sigh of relief over this one.

Aeolun 1y ago
> Damn. That's pretty quick to diagnose and take action. I have to imagine that “You are flying” and “You just cut off all fuel to the engines” must generate a pretty obvious claxon of warnings.
dehrmann 1y ago
> Boeing's probably gonna have a big sigh of relief over this one. The 787 is 15 years old, and this particular plane was 10 years old. It always seemed unlikely to be a major, new issue. My money was actually on maintenance.
- sofixa 1y ago
  While unlikely, there have been issues before that took decades to surface (e.g. Aloha Airlines where a 737 manufactured more than a decade earlier became a cabriolet due to Boeing underestimating sea water corrosion and short flight cycles), or the 737 rudder issues where the planes were also 10+ years old.

alephnerd 1y ago

> It's difficult to conclude anything other than murder-suicide. Is it possible it could have been an accident or a mistake by one of the pilots? How intention-proofed are engine cutoffs?

ummonk 1y ago
You have to pull the switches out (against a spring) to be able to move them over a notch and flip them. Not really something you can just mistake for another switch or bump into by accident. I'd liken it to turning off the ignition by turning the key while driving your car. Possibly something that could happen if you're really fatigued, but requires quite a mental lapse.
- magicalhippo 1y ago
  Is it possible to rest the switch on the notch? Does the switch make contact if the switch is in the RUN position but the switch is not completely down? That is, is it possible they flipped the switches over to RUN but did not seat the switches properly, and instead leaving them on top of the notch, with later vibration causing the switches to disengage? Just trying to think of some semi-plausible non-active causes.
- deleted 1y ago
  [deleted]
- joezydeco 1y ago
  Report says the switches went to cutoff one second apart from each other. Can a human do the physical operation on two switches that quickly?
  - snypher 1y ago
    There's a good photo of them here; https://theaircurrent.com/aviation-safety/ai171-investigation-fuel-control-switches/ https://theaircurrent.com/aviation-safety/ai171-investigatio... You can do them both with one hand.

lazystar 1y ago

https://ad.easa.europa.eu/ad/NM-18-33 https://ad.easa.europa.eu/ad/NM-18-33 well hold your horses there... from the FAA in their 2019 report linked above: > The Boeing Company (Boeing) received reports from operators of Model 737 airplanes that the fuel control switches were installed with the locking feature disengaged. The fuel control switches (or engine start switches) are installed on the control stand in the flight deck and used by the pilot to supply or cutoff fuel to the engines. The fuel control switch has a locking feature to prevent inadvertent operation that could result in unintended switch movement between the fuel supply and fuel cutoff positions. In order to move the switch from one position to the other under the condition where the locking feature is engaged, it is necessary for the pilot to lift the switch up while transitioning the switch position. If the locking feature is disengaged, the switch can be moved between the two positions without lifting the switch during transition, and the switch would be exposed to the potential of inadvertent operation. Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown. Boeing informed the FAA that the fuel control switch design, including the locking feature, is similar on various Boeing airplane models. The table below identifies the affected airplane models and related part numbers (P/Ns) of the fuel control switch, which is manufactured by Honeywell. > If the locking feature is disengaged, the switch can be moved between the two positions without lifting the switch during transition, and the switch would be exposed to the potential of inadvertent operation. Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown

noduerme 1y ago
What is "01 second" as quoted above? If it's 1 second, you could possibly conclude that it was intentional. If it's 0.1 second you might think it was an accident and the lock was disengaged.
- JumpCrisscross 1y ago
  One second. (Runway four is frequently zero four because radios.)
  - deleted 1y ago

ummonk 1y ago

Yeah and the other pilot flipped the switches back on and one of the engines started spooling up but it was too late. Murder-suicide looks like the likely conclusion, given that flipping the cutoff switches requires a very deliberate action. That said, it's not entirely impossible that due to stress or fatigue the pilot had some kind of mental lapse and post-flight muscle memory (of shutting off the engines) kicked in when the aircraft lifted off.

gosub100 1y ago
> Murder-suicide looks like the likely conclusion But why cutoff the fuel instead of flying into terrain? It's such a passive action
- lotsofpulp 1y ago
  I imagine it would be more difficult to fly into terrain without a cooperative co pilot than cutting the fuel just after take off.
- ummonk 1y ago
  For whatever reason, the Egypt Air 990 pilot initiated his murder-suicide by pulling the thrust to idle and then flipping the fuel cutoff switches.
breadwinner 1y ago
> post-flight muscle memory (of shutting off the engines) kicked in Possible, and if so it is too early to conclude it was murder-suicide. See also: https://www.thehindu.com/news/national/dgca-slaps-80-lakh-fine-on-air-india-for-overworking-pilots/article67981033.ece https://www.thehindu.com/news/national/dgca-slaps-80-lakh-fi...
- Jtsummers 1y ago
  The report shows 0 flight hours during the prior 24 hours for both pilots, and 7 hours and 6 hours each for the previous 7 days. It seems they were both fresh pilots for this flight.

bgwalter 1y ago

Does the Flight Data Recorder consider the physical position of the fuel switches or does it get the information from some fly-by-wire part that could be buggy? The conversation would suggest that the switches were in CUTOFF position, but there is also a display that summarizes the engine status. There is no conversation that mentions flipping the switch to RUN again. EDIT: Why is there no Cockpit Video Recorder? The days of limited storage are over.

WalterBright 1y ago
I've had discussions on HN with people who insisted that having a video camera always pointed out the control tower at the runway was some sort of impossibility. Despite every 7-11 having such a system. This would leave accident investigators with a lot of work to do to try to figure out how a collision happened.
tekla 1y ago
Yes there is.
deleted 1y ago
[deleted]
ssl232 1y ago
> EDIT: Why is there no Cockpit Video Recorder? The days of limited storage are over. Pilots unions are dead against it.
- ekianjo 1y ago
  And Pilots end up dead because of it.
- bombcar 1y ago
  And now some pilots are dead. Just allow cockpit video recorders, and if they're ever used for anything, the pilots (or their heirs) get $250k in cash.
- gnulinux996 1y ago

dcreater 1y ago

Do you know if the mechanical position of the switch guarantees its electronic state without any possibility for hardware malfunction? If no, then you are claiming a person made one of the most grave acts of inhumanity ever. This sounds to me like an electronics issue - an intermittent, inadvertent state transition likely due to some PCB component malfunction

cosmicgadget 1y ago
Murder-suicide has happened on a few occasions. How many times has your malfunction occurred on an aircraft fuel system?
- bgwalter 1y ago
  Not precisely the electrical malfunction, but dual engine shutdown has occurred, fortunately after landing: https://www.aerosociety.com/news/ana-787-engine-shutdown/ https://www.aerosociety.com/news/ana-787-engine-shutdown/
  - shash 1y ago
    Different engine (those are Trents and this was a GEnx), but yeah, that _did_ happen.
  - cosmicgadget 1y ago
    That doesn't seem to be a malfunction at all.
stefan_ 1y ago
And then 10s later the switches magically fixed themselves? The likely not electronically connected switches since that would compromise engine redundancy?
- ekianjo 1y ago
  The rodents were remorseful and fixed the cables in the meantime. /s

__turbobrew__ 1y ago

I wonder if the switches are still in tact after the crash? Can they verify that the switches are mechanically sound? If so, seems highly likely it was intentional.

userbinator 1y ago
I'd suspect the wiring leading from the switches to the engine controllers first, especially since it looked like both circuits cut out nearly at the same time.
- shash 1y ago
  This is speculation again since I don't really know, but my understanding of aviation engineering is that there would be two separate controllers for each engine connected to these two switches. At no point would they be connected to the _same_ control unit. The really short time (~1s) between the two being cutoff is the difficult thing to explain here.
  - userbinator 1y ago
    Are the wires leading up to those switches on the console also kept separate, or are they just bundled together as part of the same harness (presumably before it splits to go to the engines)? I think that's also important in understanding the possible failure modes.
pigbearpig 1y ago
There are pictures of them in the report.
deleted 1y ago
[deleted]

Waterluvian 1y ago

Not that humans are known to behave rationally when trying to commit suicide, but it’s interesting that the switches were re-engaged successfully without protest or a fight. It’s just an interesting detail to wonder about.

yardstick 1y ago
The reasoning I’ve heard is: it didn’t matter anymore, the damage was already done and there was no way any attempts at recovering from it would have been successful.
- ExoticPearTree 1y ago
  There would have been an inaction on the part of the pilot that did this, but it is not mentioned in the CVR transcript. Hard to believe the other pilot wouldn’t have said anything. Recovering the airplane and have some people survive the crash are two very different things.

userbinator 1y ago

and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec Or more precisely, the signals which come from them were found to behave as such. Without any audible record of turning the switches off, I wouldn't blame the pilots without first checking the wiring and switches themselves for faults. This reminds me of the glitches caused by tin whiskers.

crtified 1y ago
I agree, there's a significant distinction between "the switches were (physically) flipped" and "the circuit was opened/closed". In this case, it may be a moot distinction, particularly if no physical evidence of fault or tampering has been discovered in investigation. But, in theory, very important - there's a lot of potential grey-area between the two statements. The proximity of the incident to the ground may also increase the possible attack vectors for simple remote triggers.
- shash 1y ago
  My understanding from what we've been reading is that these are physical switches that cannot be moved using remote triggers. Wildly speculating, there _may_ be a possibility that the _effect_ of the switch may be triggered remotely, if it's a signal being read by a control unit or computer of some sort that then actuates the specific electromechanical components. But it would seem impossible to move a physical switch to do it. As an analogy, if you have a smart lock, you can remotely trigger the _effect_ of turning the key using (let's say a bluetooth control), but if a key is inserted into the keyhole, unless there is two-way mechanical linkage, that key _will not turn_.
  - crtified 1y ago
    Any switch becomes irrelevant if a saboteur has access to the behind-the-panel wires that the switch operates. But I presume that would leave physical evidence which would have been discovered by now. Presume, but cannot be certain.
1y ago