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Preliminary report into Air India crash released

(www.bbc.co.uk)
340 points cjr | 1 comments | 11 Jul 25 20:23 UTC | HN request time: 0.266s | source
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decimalenough ◴[11 Jul 25 21:24 UTC] 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 ◴[11 Jul 25 21:31 UTC] 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 ◴[11 Jul 25 22:46 UTC] 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. lupusreal ◴[12 Jul 25 12:20 UTC] 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.