Most active commenters
  • sillysaurusx(7)
  • rogerrogerr(7)
  • anonymousiam(4)
  • umanwizard(3)

←back to thread

327 points cjr | 50 comments | | HN request time: 2.329s | source | bottom
1. suyash ◴[] No.44537670[source]
Is there a possibility that they got hacked and remotely toggled ?
replies(1): >>44537689 #
2. rester324 ◴[] No.44537683[source]
These are not facts. These are mostly speculation.
3. andrewinardeer ◴[] No.44537688[source]
> it was one of the most horrific mass murder in history

This implies intent.

> One pilot asked “why did you turn them off?” and the other said “I didn’t.”

To me this reads like an unintentional error with colossol implications.

Are you suggesting there was malicious intent and then a delibrately crafted denial by the perpetrator?

replies(3): >>44537698 #>>44537703 #>>44537757 #
4. sillysaurusx ◴[] No.44537689[source]
Sadly not. It’s a physical switch with no capability of a remote toggle. The flight data recorder clearly shows one was toggled off within a second of the other, which rules out almost every non-intentional scenario.
replies(3): >>44537727 #>>44537777 #>>44538240 #
5. umanwizard ◴[] No.44537695[source]
I don’t understand this part of your post:

> This was not suicide, or murder-suicide; it was one of the most horrific mass murders in history, in which the guy that did it happened to lose his life in the process.

Why wouldn’t this qualify as a murder-suicide, assuming your theory is correct?

replies(1): >>44537736 #
6. sillysaurusx ◴[] No.44537698[source]
I am, and I’m willing to stake my reputation on it. If I’m wrong, I’ll hang up my hat and never cover live news again.

Pilots are drilled from day one that the fuel switches are sacred. After a few accidents where one engine failed and the pilot accidentally turned off the remaining functional engine, the training was overhauled so that it would be impossible for it to be an easy action done by mistake. One pilot is required to ask the other for confirmation before toggling the switch, I believe. It wouldn’t be something you’d do from muscle memory.

replies(1): >>44537746 #
7. killingtime74 ◴[] No.44537703[source]
I mean lots of people in prison say they are innocent
8. anonymousiam ◴[] No.44537707[source]
The report says the co-pilot was flying.

The report says the black box reports the fuel cutoff switches being activated. That doesn't necessarily mean that either of the two pilots activated them, it just means that the fly-by-wire system reacted to a fuel cutoff event.

"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 cutoff.

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."

replies(1): >>44537791 #
9. acjohnson55 ◴[] No.44537727{3}[source]
What if he mistook the switch for a different switch?
replies(1): >>44537820 #
10. sillysaurusx ◴[] No.44537736[source]
I guess I let my emotions get in the way. But nobody seems to be saying that we’ve witnessed one of the worst acts of mass murder in history. Most of the notorious serial killers don’t come close to killing 300 people.

It feels qualitatively different than someone pointing a gun at someone else and then themselves, which is usually what pops to mind when you hear “murder-suicide”.

You’re correct though, it qualifies.

11. janice1999 ◴[] No.44537746{3}[source]
> If I’m wrong, I’ll hang up my hat and never cover live news again.

It easy to say that when you know there's likely no way to prove or disprove whether it as an accident or not. Unless a pilot left a note stating his future intentions, there's no way to determine their state of mind.

replies(2): >>44537770 #>>44538021 #
12. kraigspear ◴[] No.44537757[source]
The switches require that you pull them out, move them to the end position and then push them back down, and it was two switches. It could have still took off on one engine. This is essentially the turn off plane switch. It would seem to almost impossible that it would be an accident.
replies(1): >>44538578 #
13. sillysaurusx ◴[] No.44537770{4}[source]
Someone took their hand, pulled one spring-loaded switch into the off position, and then did it the other switch moments later. Is there any way that could be accidental?

If there was no mechanical failure, the only remaining possibility is deliberate action. And if it was mechanical failure, we’d see an emergency air worthiness directive being issued, which we haven’t.

replies(3): >>44537835 #>>44537897 #>>44537977 #
14. nine_k ◴[] No.44537777{3}[source]
Is this a switch that has a dedicated connection to the corresponding cutoff valve? Or does it go through some common digital bus that passes commands? If so, how well is this bus protected?
replies(1): >>44538533 #
15. marze ◴[] No.44537788[source]
You mention "brain fart". There is certainly a long history of pilots selecting the wrong lever, or wrong switch. So, it is possible the pilot who denied switching the fuel off thought he had switched something else.
replies(2): >>44537815 #>>44537931 #
16. rogerrogerr ◴[] No.44537791[source]
> That doesn't necessarily mean that either of the two pilots activated them

It does:

1. Those switches have physical interlocks and cannot be manipulated by any computer system.

2. The flight data recorder is measuring the position of the switches; they aren't inferring the position from some system state. There's a "position of this switch" channel.

The switches were physically moved in the cockpit, that's basically ground truth. The question now is who and why.

replies(2): >>44537827 #>>44538593 #
17. sillysaurusx ◴[] No.44537815[source]
My understanding is that after several incidents of pilots shutting off the wrong engine, the training was overhauled so that from day one they treat fuel switches as sacred. I heard that it’s required to ask for confirmation before toggling the switch, just to be absolutely certain. It’s not really something that can be done by muscle memory during flight, and especially not during takeoff.

If he was trying to do something else, he would have called it out. E.g. an audible “gear up.”

replies(1): >>44537858 #
18. rogerrogerr ◴[] No.44537820{4}[source]
It's an entirely different shape, different location, and different motion from any other switch they could be looking for. Suicide is a way more likely explanation.

And, it's _two_ switches.

19. anonymousiam ◴[] No.44537827{3}[source]
What is the path of the wires from the switch onward? Do they go into a digital input of the flight computer, or do they directly feed the fuel control valves?

https://simpleflying.com/boeing-787-technical-features-guide...

" Advanced electric controls

The 787 entered service with an improved fly-by-wire flight control system. Rather than mechanical processes, the systems convert flight deck crew inputs into electrical signals. Still, there were additional advancements with the type."

replies(1): >>44537939 #
20. ◴[] No.44537831[source]
21. arcfour ◴[] No.44537832[source]
As someone with no qualifications on this beyond occasionally playing some flight simulators, I can't think of a reason you would ever intentionally move the switches in flight (barring an emergency like a leak or fire or something) and unintentionally doing so seems extremely unlikely since generally "switches meant to be operated on the ground" are located well out of the way of "switches meant to be operated in flight". Though I believe Boeing does have them by the thrust levers, every type of fuel control switch I've seen has some sort of guard or mechanism that makes it effectively impossible to move the switch by simply bumping it.

So I can't imagine how it could have been done accidentally.

22. ◴[] No.44537835{5}[source]
23. marze ◴[] No.44537858{3}[source]
Also, it took 10 and 14 seconds to switch them back on. If it was an accidental switch, you would think it would have been quicker to switch them back.
24. umanwizard ◴[] No.44537897{5}[source]
People do things bizarre, inexplicable things all the time. It's called a brain fart... the human brain is complicated, sometimes wires just get crossed.

Honestly I think the chances are good that you're right, but the way you're presenting it as absolutely certain strikes me as overconfident, borderline arrogant.

Also, what's with the whole "staking your reputation" thing? What reputation? Are you some kind of famous journalist? Is there some reason we should care about you "covering live news" ? Serious questions -- I personally have no idea who you are.

replies(2): >>44537997 #>>44538055 #
25. tim333 ◴[] No.44537931[source]
If you look at the photo https://theaircurrent.com/aviation-safety/ai171-investigatio... it would be pretty hard to get them by mistake.
replies(1): >>44538225 #
26. rogerrogerr ◴[] No.44537939{4}[source]
Can't find a definitive source right now, but everything is implying there are discrete lines - at least one for command signal to the FADECs, and a separate sense line to the DFDAU for packaging up and sending to the EAFR. That lines up with design philosophy on this stuff of sensing control input data as close to the source as you can get.
replies(1): >>44538054 #
27. toast0 ◴[] No.44537977{5}[source]
The report indicates the cut off switches were found, and were in the RUN position. However, the report does not indicate if the locking mechanism was functional; given the thermal damage, it might not be possible to determine.

I'm also interested in the earlier switch defects where the switches were installed with the locking mechanism disengaged on some 737s and inspection was advised for 787, but the incident aircraft was not inspected.

The airworthiness directive for that [1] indicates switches with locking disengaged should be replaced, but I wonder if it's possible to reingage the locking somehow, which could result in a situation where the locking wasn't engaged, the switches changed inadverdently and then when restored the run position the lock was engaged... that's a big reach, of course.

All that said, assuming the switch was working as designed, there's a semantic argument around deliberate and intentional. If the switch requires specific action, it's fair to call it deliberate action; but if the switcher thought they were activating a different switch, it's not murder.

Either way, there's no sense rushing to a conclusion of murder. Assuming one of the pilots activated the switch, they have already died and they are beyond the effects of human judgement; so we may as well wait for further information.

[1] https://ad.easa.europa.eu/blob/NM-18-33.pdf/SIB_NM-18-33_1

28. rogerrogerr ◴[] No.44537997{6}[source]
> I personally have no idea who you are

I also don't recognize this guy's name, but I do find it ironic that his profile is possibly the most well-linked to a other identities I've ever seen on HN: https://news.ycombinator.com/user?id=sillysaurusx

29. cosmicgadget ◴[] No.44538021{4}[source]
The CVR might be pretty illuminating.
30. anonymousiam ◴[] No.44538054{5}[source]
Thanks for looking. I worked for Boeing (satellites, not airplanes) for a good part of my career, and I was there when Dennis Muilenburg pushed through his cost saving measures. It was the same culture that created the problems with the 737-MAX. Experienced design engineers were replaced/outsourced and the culture of safety was sacrificed. One example here:

https://www.cnn.com/2019/04/30/politics/boeing-sensor-737-ma...

787 (Dreamliner) was pushing hard for weight reduction, and it would not surprise me at all if the switch output fed a digital computer input rather than routing directly to the fuel shutoff valves, but I don't have any direct knowledge of this.

replies(1): >>44538641 #
31. sillysaurusx ◴[] No.44538055{6}[source]
Well, you do now. :)

It’s mostly a very public "If I’m wrong, I won’t ever do this again." I’ve been writing informative HN comments since 2008 on various accounts. It’s a big deal to me not to spread misinformation or be mistaken in a situation like this.

The victims also deserve to be acknowledged. At this point the overwhelming body of evidence points to a deliberate act. Pilots are trained never to touch the fuel switches in flight, and (I believe) there is a verbal confirmation required before toggling. This captain had over 8,000 hours.

The reason I’m so confident is because I trust the system. It’s designed so that if either of the two pilots do anything, they verbally call it out, e.g. "gear up." A callout like that followed by fuel switch cutoff would indicate it was accidental. But as far as I know, there was no callout.

The pilot flying is also the one who asks for gear up and such. It’s the job do the pilot monitoring to perform those actions.

Suppose it was accidental. That would mean the pilot flying was fiddling with switches instead of flying; that’s against SOP. Or it would mean the pilot monitoring was performing uncommanded actions, which is also against SOP. It’s not something that happens on a whim. Both are contradictions, hence, no accident.

As for being overconfident or arrogant, what matters to me is accuracy, and passing along that accuracy. No one seemed to be willing to publicly call this a malicious action, so I did. If I’m wrong, you can be sure I’ll feel terrible for weeks, post an apology in the thread that shows I was wrong, and then bow out in disgrace, never to cover news again.

People here did the same thing when the common belief was that there was a non-zero chance of nuclear war. I was one of the few voices in that thread saying absolutely not, stop stressing yourself out for no reason.

I’m simply one voice of many. As always, it’s up to the reader to decide what to believe.

replies(2): >>44538378 #>>44538630 #
32. analog31 ◴[] No.44538225{3}[source]
I have a couple of those type of switches, though smaller, in my parts bin. They were from some piece of surplus equipment that got junked. Where I've seen them used is in a crowded control panel where they might just get bumped. The two red plastic levers to the left are another type of safety switch: The lever is spring loaded, and covers the handle of a toggle switch.

In my view it would be quite hard to move them by accident, and probably not possible to move at once.

It would be interesting to know if the plane has any other switches of the same type, that are routinely activated.

replies(1): >>44538382 #
33. alvah ◴[] No.44538240{3}[source]
Happily not. If this were possible, it would open up a whole universe of problems.
34. zahlman ◴[] No.44538370[source]
> This was not suicide, or murder-suicide; it was one of the most horrific mass murders in history, in which the guy that did it happened to lose his life in the process.

Even taking intent for granted, to deny suicide in a case like this would be to suppose that the person responsible expected to survive while everyone else died. What could possibly support that conclusion?

replies(2): >>44538491 #>>44538623 #
35. maxbond ◴[] No.44538378{7}[source]
> It’s a big deal to me not to spread misinformation or be mistaken in a situation like this.

Then why not either wait until there's more information or temper your remarks by acknowledging there's still ambiguity? That would directly hedge against spreading misinformation, whereas staking your reputation on it and then shutting up if you're wrong only works after the misinformation has spread and doesn't seem very productive.

I think the right response to realizing you've spread misinformation (in the event that you turn out to be mistaken [I think it's 60-40 in favor of deliberate]) is to temper your statements and rededicate yourself to checking the facts, not removing yourself from the discussion altogether. And if you were keeping your mouth shut, wouldn't you continue to see discussions you could meaningfully contribute to, and after a while wouldn't you wonder whether anyone was really benefitting from your silence?

replies(1): >>44538572 #
36. MichaelZuo ◴[] No.44538382{4}[source]
There’s no way even the clumsiest person could accidentally pull both out, rotate, and push back in, accidentally within 1 second.
37. umanwizard ◴[] No.44538491[source]
He appears to have meant something like “this isn’t just common murder-suicide: it is a particularly heinous version of murder-suicide that I wish there were a stronger word for” but phrased it confusingly.
38. appreciatorBus ◴[] No.44538533{4}[source]
Another commentator has pointed out that the flight data recorder records two signals - one for the switch itself, and one for the actual valve movement.

I take your point that we should always be suspicious of complicated, digital buses, and this is not the final report, so there’s still plenty of time to uncover weirdness. However, if the flight date reporter shows the switch being thrown, and then a few milliseconds later, shows the valve starting to close, and the same sequence happening shortly there after on the second switch and valve, I feel this would really limit the likelihood of any digital shenanigans.

39. sillysaurusx ◴[] No.44538572{8}[source]
I was about to leave a big reply, but then I remembered that the guidelines ask that we only comment when feeling intellectual curiosity. That’s not what I’m feeling now, so I’ll go spend the evening with my daughter. I hope you have a nice evening as well.
replies(1): >>44538588 #
40. schiffern ◴[] No.44538578{3}[source]
Not possible it's an "I bumped it" type of accident, maybe.

It's quite possible it's a "performed the wrong muscle memory at the worst possible moment" type of accident. This is unlikely, but anyone who thinks such a mistake is impossible doesn't know anything about human factors.

Unlikely just means "low probability." There are thousands of flights per day, so it's only a matter of time.

41. maxbond ◴[] No.44538588{9}[source]
Sorry if I touched a nerve, wasn't my intention. My question was genuine and not intended to needle or carp. I hope you have a nice evening as well.
42. userbinator ◴[] No.44538593{3}[source]
No, lacking other evidence (e.g. CVR recording) it doesn't mean they have been moved. The wiring in between the switches and the engine+FDR could've also developed an intermittent fault.

The fact that your car's engine stops doesn't mean you turned the ignition switch off. Anyone who has had to troubleshoot a car with intermitent electrical faults knows that.

replies(1): >>44538950 #
43. arp242 ◴[] No.44538623[source]
Maybe that one guy who survived did it? Are there fuel cutoff switches near seat 11A?
44. aspenmayer ◴[] No.44538630{7}[source]
> It’s mostly a very public "If I’m wrong, I won’t ever do this again." I’ve been writing informative HN comments since 2008 on various accounts. It’s a big deal to me not to spread misinformation or be mistaken in a situation like this.

I understand that you appear earnest. However, your history of multi-accounting on this site makes your promise to never post on a given topic again meaningless to me, because I have no expectation that you wouldn’t continue to post about it on other accounts that we don’t know about at this time, possibly because they haven’t even been created yet.

45. unyttigfjelltol ◴[] No.44538641{6}[source]
In that case, it could be true both that neither pilot manipulated the switch and that the system recorded a dual fuel cutoff.
replies(1): >>44538956 #
46. rogerrogerr ◴[] No.44538950{4}[source]
We have other evidence - the crew noticed, and then moved them back to the Run position, and the engines responded as you’d expect.

The switches physically moved, and there is no motor to actuate them without physical intervention.

47. rogerrogerr ◴[] No.44538956{7}[source]
Then why do we see the pilots notice the cutoff, move the switches back, and the engines respond as expected? The switched cannot move themselves. We’d expect to hear more commentary and confusion if the cutoff was active and the switches still in Run.
replies(1): >>44539008 #
48. anonymousiam ◴[] No.44539008{8}[source]
There would have likely been an indication on the glass cockpit displays that the fuel had been cut off, perhaps the pilot flying noticed this and asked the captain.
replies(1): >>44539076 #
49. rogerrogerr ◴[] No.44539076{9}[source]
Yes, there is, but the reaction to that would be to look at the position the cutoff switches were in. We didn’t hear “wtf, they’re in Run” - the report says they just moved them from Cutoff to Run and the engines responded as expected.

I think you have to really reach to make this not pilot error. I know it’s appealing to call this a Boeing problem, but the evidence just from this prelim report is very compelling.

If you think it’s not pilot error, you can make some fake Manifold dollars: https://manifold.markets/JohnHughes/what-will-be-the-officia...

replies(1): >>44540058 #
50. userbinator ◴[] No.44540058{10}[source]
Until we hear the actual CVR audio, I don't think we can assume much. They are under a very high stress at that point in the flight, and while the "WTF?" might be going through their minds, all they could've resorted to is toggling the switches off and on again.