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388 points cjr | 3 comments | | HN request time: 0.634s | source
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decimalenough ◴[] No.44536914[source]
> 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.

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burnt-resistor ◴[] No.44539178[source]
> 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.

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sugarpimpdorsey ◴[] No.44539262[source]
> One of them moved the levers. It could've been an unplanned reaction, a terrible mistake, or it could've been intentional.

Fuel levers are designed to only be moved deliberately; they cannot be mistaken for something else by a professional pilot. It's literally their job to know where these buttons are, what they do, and when to (not) push them.

It's not arrogance to assume the most likely conclusion is true, despite how uncomfortable that outcome may be.

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burnt-resistor ◴[] No.44539580[source]
> cannot be mistaken for something else

Assumption. Big ass assumption.

Pilot are trained until actions are instinctual and certain memory items are almost unconscious. But pilots are still people and people are fallible and make mistakes, and sometimes act unreasonably. Intent cannot be determined without clear evidence or statements because that's now how thoughts locked away in people's minds work.

> It's not arrogance to assume the most likely conclusion is true

You don't know this. This is beyond the capability to know and is therefore pure speculation. That is the definition of arrogance.

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Voloskaya ◴[] No.44541220[source]
> sometimes act unreasonably. Intent cannot be determined without clear evidence or statements because that's now how thoughts locked away in people's minds work.

By this logic it would be impossible to ever find anyone guilty of murder (or any other nefarious action) with intent unless they explicitly state that it was in fact their intent. Obviously this is not how justice works anywhere, because at some point you have to assume that the overwhelmingly most likely reason for doing an action was the true reason.

If someone pulls out a gun, cock it, aim it at someone and pull the trigger, killing the other person, should we hold off any judgement because they might have done it purely mechanically while in their head thinking about the lasagna they are going to cook tonight and not realizing what they were doing ?

The fuel cut off switches have a unique design, texture and sequence of action that need to be taken to actuate them, they don’t behave like any other switch. Pilot are also absolutely not trained to engage with those particular switches until it’s instinctual.

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jltsiren ◴[] No.44541416[source]
Courts do not seek to establish the truth. They aim for a reasonable balance between false positives (innocents convicted of crimes they didn't commit) and false negatives (criminals allowed to go free). In practice, the false positive rate is probably around 5%, and innocents go to prison all the time.

Air accident investigations mostly deal with one-in-a-billion freak occurrences. Commercial aviation so safe and reliable that major accidents rarely happen without a truly extraordinary cause.

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agubelu ◴[] No.44542541[source]
Yet Occam's razor still applies
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jltsiren ◴[] No.44543145[source]
That's not what Occam's razor means. It means that after you have exhausted all options to rule out competing hypotheses, you choose the simplest one that remains, for the time being.

Consider some explanations that are consistent with the evidence presented so far. And remember that the purpose of the investigation is to come up with actionable conclusions.

1. One of the pilots randomly flipped and crashed the plane for no reason. In this case, nothing can be done. It could have happened to anyone at any time, and we were extraordinarily unlucky that the person in question was in position to inflict massive casualties.

2. Something was not right with one of the pilots, the airline failed to notice it, and the pilot decided to commit a murder-suicide. If this was the case, signs of the situation were probably present, and changes in operating procedures may help to avoid similar future accidents.

3. One of the pilots accidentally switched the engines off. The controls are designed to prevent that, but it's possible that improper training taught the pilot to override the safeties instinctively. In this case, changes to training and/or cockpit design could prevent similar accidents in the future.

Because further investigation may shed light on hypotheses 2 and 3, it's premature to make conclusions.

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1. manquer ◴[] No.44544685[source]
Given the fly by wire nature of 787 there is an also fourth option.

The physical switch was not touched at all , and the software has a bug under some rare conditions which cut off the supply to both engines.

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2. sgerenser ◴[] No.44546527[source]
Extremely unlikely, since we can hear the other pilot ask why he turned the fuel switches. If it was an electrical glitch, he wouldn’t be able to see that they are in the cutoff position.
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3. manquer ◴[] No.44546850[source]
All we know is the pilot flying is only asking whether the pilot monitoring if he cut off

- We don't know if he meant the switch specifically at all. He could also have meant engines or thrust in general. There are many other visual signals and UX indicators to know if engines are spinning down. Thrust levels, to RPM to falling speed, change in angle of attack, rate of climb, even engine noise, vibrations you expect at full thrust etc.

- We also don't know if the switch was physically in cut off position in the first place or even if was the pilot noticed that specific visual signal and meant that when he spoke.

If it was a software issue, it is possible the switch was properly positioned, and software issue cut engine was cutoff, the display screens and other lights would show that.

In such a scenario, the pilot(s) would have likely checked with each other first if they did something as in the audio and manually tried restarting the engine as they seem to have done.

I am not saying it is a bug or any specific fault scenario, Just that it too early, we don't yet have enough information to say what is likely at all.