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294 points cjr | 28 comments | | HN request time: 1.863s | source | bottom
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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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lazystar ◴[] No.44536962[source]
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

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1. sillysaurusx ◴[] No.44537557[source]
https://www.youtube.com/live/SE0BetkXsLg?si=LPss_su3PVTAqGCO

Both of these extremely-experienced pilots say that there was near zero chance that the fuel switches were unintentionally moved. They were switched off within one second of each other, which rules out most failure scenarios.

If it was an issue with the switches, we also would have seen an air worthiness directive being issued. But they didn’t, because this was a mass murder.

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2. longos ◴[] No.44538126[source]
If this is what actually happened it would be the second in recent memory: https://en.wikipedia.org/wiki/Germanwings_Flight_9525.
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3. decimalenough ◴[] No.44538319[source]
Third, since there's no other plausible explanation for this and China has classified the report.

https://en.wikipedia.org/wiki/China_Eastern_Airlines_Flight_...

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4. lanna ◴[] No.44538365{3}[source]
Fourth? https://en.wikipedia.org/wiki/Malaysia_Airlines_Flight_370#M...
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5. pineal ◴[] No.44538479{4}[source]
Fifth. https://en.wikipedia.org/wiki/EgyptAir_Flight_990
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6. CBMPET2001 ◴[] No.44538773{5}[source]
Sixth (and this one is pretty indisputable): https://en.wikipedia.org/wiki/LAM_Mozambique_Airlines_Flight...
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7. stickfigure ◴[] No.44538920[source]
260 souls is well into the territory of horrible terror attacks. By comparison, only 14 people died from the sarin gas attacks on the Tokyo subway.
8. ekianjo ◴[] No.44538988{4}[source]
We dont know about that one at all.
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9. ◴[] No.44539054{6}[source]
10. bdangubic ◴[] No.44539114{5}[source]
we do here on HN :)
11. chrisandchris ◴[] No.44539382[source]
> If it was an issue with the switches, we also would have seen an air worthiness directive being issued.

I do not trust these air worthiness directives 100.0%. The 737 Max also required two catastrophic failures before it was grounded.

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12. decimalenough ◴[] No.44539897[source]
The issue with the 737 MAX became evident within months of the plane's launch. By contrast, the Dreamliner has accumulated over a decade of flying history across over 1000 aircraft with precisely zero fatal accidents.
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13. 0_-_0 ◴[] No.44539905[source]
Maybe as the PIC was guarding the lower end of the throttle he rested the rest of his hand on the panel cover below the throttle and, while pushing forward on the throttle, let the side of his hand slide down right onto the switches, the likeliness of which would have been exacerbated by a rough runway or a large bump. It's unlikely the left and right part of his hand would have contacted the cutoff switches at the same time, hence the delay between the two switches being actuated. Of course this relies on the safety locks not working properly, which is something that hand been reported.
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14. rurban ◴[] No.44539974[source]
Only the captain was extremely experienced, the FO was a rookie. He wouldn't have had enough hours for an European airline
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15. lazystar ◴[] No.44540082{5}[source]
please. pilot puts everyone to sleep but himself, turns everything off, then does a flyby of his hometown and then puts himself to sleep? the only one more obvious is the german one.
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16. ekianjo ◴[] No.44540228{6}[source]
without a black box all of this is supposition.
17. jmtulloss ◴[] No.44540362[source]
This is not true at all.

Perhaps there are more qualifying statements that you meant to include? The certification and type rating requirements certainly differ between agencies, but in terms of raw number of flight hours it’s easy to find that this statement is false.

18. fakedang ◴[] No.44540436[source]
He had 1100 hours on the 787 alone. 3200 hours altogether. Most media sources just went with the former figure as his overall experience.
19. sgt101 ◴[] No.44540738{3}[source]
Absence of evidence isn't evidence of absence.

The fact that the pilots denied that they had shut the switch (one asking the other why they had done so and the other denying it), and that they restarted the engines should be taken into account. Ok, murder suicide is definitely on the table but I would want to see some other reasons for believing that this is so.

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20. jon_smark ◴[] No.44541067{4}[source]
Sorry to nitpick, but for a good Bayesian, absence if evidence is evidence of absence. If you want the aphorism to be technically correct, you should say "absence of proof is not proof of absence".

A note on the terminology: "evidence" is a piece of data that suggests a conclusion, while not being conclusive by itself. Whereas "proof" is a piece of data that is conclusive by itself.

21. raverbashing ◴[] No.44541395[source]
I'm not disagreeing with you I think this was manually done

But here's the thing a "near zero chance" when we are talking about an actual event changes the math

Maybe there's a combination of vibration and manufacturing defect or assembly fault or "hammer this until it works" that can cause the switches to flip. Very unlikely? Yes. Still close to 0% but much more likely in the scenario of an accident

Of course AAIB/NTSB etc didn't have any time to investigate the mechanical aspects of this failure

So yeah it was probably done intentionally but the "switches turning off by themselves" should not be excluded

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22. VBprogrammer ◴[] No.44541468[source]
It feels quite uncomfortable to me. I remember using this exact example of why the changes after the German wings crash wouldn't prevent a murder suicide in the future.
23. briandear ◴[] No.44541488[source]
My buddy says the same, he’s a 787 captain for United. Essentially impossible to accidentally turn off those switches. My buddy isn’t “evidence” of course, but actual airline captains are all saying similar things.
24. lupusreal ◴[] No.44541549[source]
A few years ago I was working at a company that used a robotic arm when an accident occurred. The robot was powered off for maintenance but suddenly turned on, pinned a worker's arm, and threw him against a wall. His arm had numerous fractures and he had severe head injuries but survived.

The other worker in the building was in absolute shambles and couldn't understand what had happened. The CCTV footage was then checked and showed that worker looking at the other while reaching for the power switch and turning on the machine. The switch was not locked out and tagged out, but it was the only switch like it on the whole panel, large and required significant force to turn. No way to accidentally bump it, and the video showed him clearly turning the handle.

He was obviously fired, but no criminal charges were ever brought against him. He had no plausible motive for wanting the other man dead, was severely distraught over the incident. It was simultaneously obvious that he had turned the lever deliberately and had not meant to turn the leaver. A near-lethal combination of muscle memory and a confusion caused the accident. If the lever had been locked and tagged out, that probably would have interrupted his muscle memory and prevented the accident, but it wasn't.

Point is, something can be simultaneously impossible to do inadvertently, but still done mistakenly. A switch designed to never be accidentally bumped, to require specific motions to move it, can still be switched by somebody making a mistake.

25. lanna ◴[] No.44541554{5}[source]
Hence the question mark
26. briandear ◴[] No.44541599[source]
Nope. First of all, the FO was the “pilot flying” and thusly controls the throttle. The fuel shutoffs are on the left side, well clear of the range of motion throttle operation for the right seat.

If the Captain were controlling throttles, it for some reason he could contort his wrist to accidentally open the red cutoff switch guards, the switches themselves move in the opposite direction of the pivot of the switch guard. And to have that happen to both switches — one second apart. That would be astronomically (not to mention anatomically) improbable: you can’t have your hand on the throttle and also be dragging your arm on the switches unless the pilot has an extra elbow.

Further more, the 787 has auto throttles, at takeoff the pilot advances the throttles to N1, then all the way through climb out the auto throttles control the throttle unless manually disengaged.

Also a “bumpy runway” wouldn’t do anything because if those switches were activated on the roll out, the engines would shut down almost immediately: that’s the point of those switches to kill fuel flow immediately not minutes later.

And no there isn’t a report of the safety locks not working properly on the 787. The report to which you are referring was in 2018 and that was an issue with a very few 737 switches that were improperly installed. The switches didn’t fail after use, they were bad at install time. Exceedingly unlikely that a 787 was flying for 12 years with faulty switches. (Notwithstanding the fact they they are completely different part numbers.)

The 787 that crashed had been in service since 2013 which means if that were a problem in that plane, however unlikely, with hundreds of thousands of flight hours, inspections, and the 2018 Airworthiness Bulletin — that problem would have been detected and corrected years ago.

27. briandear ◴[] No.44541628[source]
We could also suggest that aliens in the cockpit did it — about the same probability. Two switches, on independent circuits, both failing within one second of each other in the exact same way?
28. jacquesm ◴[] No.44541741{3}[source]
Yes, but things age. And as they age they can fail simply due to wear that wasn't determined to be a problem before they got to that point.