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294 points cjr | 2 comments | | HN request time: 0.447s | 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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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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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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1. 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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2. 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.