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Preliminary report into Air India crash released

bbc.co.uk

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Re: Preliminary report into Air India crash released

#101

Post by marze »

sillysaurusx wrote: post #89
marze wrote: post #82

Earlier quoted context omitted.

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.

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 so…

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.

Re: Preliminary report into Air India crash released

#102

Post by lazide »

darth_avocado wrote: post #85
lazystar wrote: post #17

Earlier quoted context omitted.

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 sup…

One would assume a toggle like that would come with blaring alarms and blinking lights… right? Right?? Edit: It also seems like the engine cutoff is immediate after the toggle. I wonder if a built in delay would make sense for safety.

Low altitude, stall, and impact with terrain certainly will.

And with how low and slow they were during takeoff, those would have been going off almost instantly.

Re: Preliminary report into Air India crash released

#103

Post by lazide »

ajb wrote: post #79
snypher wrote: post #33

Earlier quoted context omitted.

There's a good photo of them here; https://theaircurrent.com/aviation-safety/ai171-investigatio... You can do them both with one hand.

If you do them both with one hand, would they not be moved at the same instant rather than 1 second apart?

They require a per-switch motion, so unlikely.

Re: Preliminary report into Air India crash released

#104

Post by lazide »

ceejayoz wrote: post #28
bob1029 wrote: post #18

> The EGT was observed to be rising for both engines indicating relight. Engine 1’s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. I know it's probably not worth the hazmat tradeoff for such a rare event, but the F-16 has an EPU powered…

I suspect any civil aviation engineer who goes "let's add hydrazine!" to fix problems has a fairly short career, lol.

Yeah, now you have at least two problems.

Re: Preliminary report into Air India crash released

#105

Post by School-Cotton »

sillysaurusx wrote: post #80
janice1999 wrote: post #77

Earlier quoted context omitted.

> 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.

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.

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.

Re: Preliminary report into Air India crash released

#106

Post by the__alchemist »

mdavid626 wrote: post #45
lazystar wrote: post #17

Earlier quoted context omitted.

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 sup…

Well, can you move it back, when accidentally activated?

Yes, and it restarts the engines, but it takes on the order of seconds; too long at that altitude. One of the pilots did that, but it was too late.

Re: Preliminary report into Air India crash released

#107

Post by cosmicgadget »

janice1999 wrote: post #83
sillysaurusx wrote: post #53

Earlier quoted context omitted.

Correct. Which means it’s the older of the two.

The report does not identify which pilot said what. Attempting to extrapolate their identities is speculation.

The report specifically says the FO was flying. The conversation is immaterial since the person who cut the fuel could have made either statement.

Re: Preliminary report into Air India crash released

#108

Post by aaron695 »

sillysaurusx wrote: post #50
lazystar wrote: post #17

Earlier quoted context omitted.

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 sup…

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…

[flagged]

Re: Preliminary report into Air India crash released

#109

Post by tim333 »

marze wrote: post #82
sillysaurusx wrote: post #57

[flagged]

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.

If you look at the photo https://theaircurrent.com/aviation-safety/ai171-investigatio... it would be pretty hard to get them by mistake.

Re: Preliminary report into Air India crash released

#110

Post by rogerrogerr »

anonymousiam wrote: post #93
rogerrogerr wrote: post #84

Earlier quoted context omitted.

> 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 basicall…

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 electric…

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.
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