Air India Flight AI171 (Boeing 787-8) Crash

[edyvw]

IIRC, 1 of 3 lost was hit by a firetruck - indeed the Triple 7 has been the work horse of modern times …

Yes. Though every time I read something about 214, I remember that local TV News station and the prank that that intern pulled off.

 

[4WD]

Yes. Though every time I read something about 214, I remember that local TV News station and the prank that that intern pulled off.

Well, they were too low - I will stop there

 

[DirectRejection]

I'm smart enough to know I have nothing of value to add to a discussion about commercial aviation but I'm deeply troubled by the idea that 260 people died because 2 switches in the cockpit were moved to the off position, whether accidentally or intentionally, and for whatever reason it wasn't possible to correct it in time to prevent the crash.

@Astro14 , a couple of questions:

If the switches were installed incorrectly or were not functioning correctly in regard to the detent feature and deliberate motion needed to turn on and off would it have been reported by a previous crew and would that ground the airplane?

In the preliminary report it says one pilot was heard to ask the other why he did the cutoff and the other pilot responded he did not do so. Is it known exactly who is speaking on these recordings and not reported at this time? If not wouldn't it be important to know who said what?

In this report the exact time the switches were transitioned from RUN to CUTOFF is known. If a hand was seen moving to that center area at that exact time stamp if there were a video would that be important to the investigation? A video might have shown one hand turning the switches off and preventing another hand from turning them back on for 10 seconds.

In another crash, maybe the one at San Francisco when the jet was too low and hit the edge of the filled land there was talk of cultural differences where a first officer would be hesitant to point out an error to the captain because it wasn't acceptable behavior to correct a superior. I don't remember the nationality and it may be the wrong crash but it was a talking point. Are you familiar with this?

I think of that crash every time I cross the San Mateo Bridge, east to west. There are often several jets on approach to SFO.

 

[y_p_w]

These switches require deliberate movement to shut down the engines. They are designed this way so they cannot accidentally be inadvertently shut off.

Much like the ignition switch on your steering column. You would never "accidentally" switch it off, while trying to do something else, because it requires a specific intentional movement to do so.

I just can't see how this could be done accidentally. Especially to BOTH switches, one after the other. You would have to use BOTH hands simultaneously to shut both switches off or on at the same time. This because the switch itself has to be lifted in order to be placed in the OFF position.

Just curious if there's any demonstration video of this being done, even if it's just in a simulator. But I would think it's like a lot of things where muscle memory is involved, even if it wasn't an intentional thing.

For example, I've stomped my left foot on nothing trying to start a car with an automatic transmission. Wasn't even thinking about it.

 

[y_p_w]

To me, unless someone can present another viable theory, that leaves malicious intent as pretty much the only option here, since there’s no indication that there was dual engine failure, the restart procedure for which would have called for movement of the switches.

I was thinking muscle memory. We all perform complex actions with our hands where we barely have to think about it. But someone who hasn't done it before would find it really difficult to do without clear instructions. Like knitting. Or typing. Sometimes the body and brain just go through the motions.

Would it be possible that one of the pilots just found his hands over the fuel switches and just shut them down without thinking about it?

 

[Expendable]

I've been in Aircraft Maintenance for 39 years, I've work on Douglas, Boeing and Airbus aircraft.
I currently work the 757, 767 and 777 and have never seen a Fuel Shut Off switch lock detent broken.
I've seen the lock detents on older none FADEC aircraft fuel shut of levers fail but never on a newer FADEC engine.

 

[john_pifer]

I was thinking muscle memory. We all perform complex actions with our hands where we barely have to think about it. But someone who hasn't done it before would find it really difficult to do without clear instructions. Like knitting. Or typing. Sometimes the body and brain just go through the motions.

Would it be possible that one of the pilots just found his hands over the fuel switches and just shut them down without thinking about it?

Well, I don’t know about that, but this is being reported by The London Evening Standard:

“Captain Mohan Ranganathan, an Indian aviation safety expert, said: “I have heard from several Air India pilots who told me he (Captain Subharwal) had some depression and mental health issues. He had taken time off from flying in the last three to four years. He had taken medical leave for that.”
According to The Daily Telegraph, Captain Sabharwal took bereavement leave following the death of his mother.”

https://www.standard.co.uk/news/world/air-india-pilot-medical-records-health-b1237973.html

 

[AZjeff]

@Astro14 , thanks for putting up with a bunch of civilians with opinions. It's a rare privilege to have a professional share first hand knowledge related to an event like this.

 

[Astro14]

So, it's your opinion that it would be all but impossible for the fuel cutoff switch position to be changed inadvertently.

That means one of the pilots deliberately moved them to CUTOFF.

And since the switches were moved to CUTOFF 3 seconds after liftoff, and there's no evidence of any engine failure or thrust deficit, doesn't the process of elimination leave malicious intent as the only option?

If the switch was moved to CUTOFF, I believe that would take deliberate, firm action on the part of one of the crew.

 

[Astro14]

Well, I don’t know about that, but this is being reported by The London Evening Standard:

“Captain Mohan Ranganathan, an Indian aviation safety expert, said: “I have heard from several Air India pilots who told me he (Captain Subharwal) had some depression and mental health issues. He had taken time off from flying in the last three to four years. He had taken medical leave for that.”
According to The Daily Telegraph, Captain Sabharwal took bereavement leave following the death of his mother.”

https://www.standard.co.uk/news/world/air-india-pilot-medical-records-health-b1237973.html

I dislike this type of speculation before the accident is completely investigated.

Impugning the character and mental health of someone before all the facts are in is really distasteful

 

[y_p_w]

@Astro14 , thanks for putting up with a bunch of civilians with opinions. It's a rare privilege to have a professional share first hand knowledge related to an event like this.

A professional, and a mod. So he could absolutely shut it down if things start going sideways.

 

[Astro14]

@Astro14 , thanks for putting up with a bunch of civilians with opinions. It's a rare privilege to have a professional share first hand knowledge related to an event like this.

I’m happy to talk about it. I’m happy to answer questions - which I did for over 40 pages in the F-14 thread.

The burr that gets under my saddle is when folks tell me how things work, what’s good, what’s bad, etc. without any experience in the actual environment.

I tend to talk about the things I know - I don’t give advice or opinion if I don’t have experience with the topic being discussed.

Not everyone shares that compunction, however.

As an aside, you’ll see experienced folks disagree in this thread. That’s OK. I’m fine with a difference in opinion when that opinion has a basis in experience.

 

[Astro14]

A professional, and a mod. So he could absolutely shut it down if things start going sideways.

Well - I appreciate the upvote.

I wouldn’t shut it down unless I thought the thread was failing to meet the BITOG standard of conduct. So, while we’ve wandered all over in discussion points, I think we’ve kept it relatively professional.

I’d be cool with my six year old overhearing these posts.

That said, it’s clear that opinions differ, so, while I might argue my position strongly, I do think the debate itself has merit.

Accordingly, the thread has remained open, even if folks don’t always see it my way.

Finally, and I think this important to re-state directly, I would never shut down a thread because of people’s positions. I would only shut it down over behavior.

If I used my position to shut down a debate based on content and not behavior, @wwillson would fire me.

And I would deserve it.

 

[billt460]

If the switch was moved to CUTOFF, I believe that would take deliberate, firm action on the part of one of the crew.

That's where my chips lay on the felt.

 

[Astro14]

That's where my chips lay on the felt.

Mine, too.

There are various theories, rumors, really, that the airplane sent a signal to shut down the engines.

That signal would mimic what happens when those switches are moved “CUTOFF”.

But my friends who fly this airplane tell me that the theory is unfounded.

The CVR discussion over the switch movement suggests that they were actually moved, and the airplane clearly suffered a dual engine power loss.

But I think the report may have been premature. There are still too many questions.

 

[AZjeff]

There are various theories, rumors, really, that the airplane sent a signal to shut down the engines.

That signal would mimic what happens when those switches are moved “CUTOFF”.

I was going to ask if the control system could be hacked to have this happen remotely or internally. The 10 seconds between switches CUTOFF and ON is curious. Not 9 or 11 seconds but exactly 10 seconds apparently.

 

[billt460]

Astro, just to be clear on how these cutoff switches work. Say you were cruising at 35,000 ft. hand flying the airplane, and you moved one of these switches to "cutoff". Then waited 30 seconds, and moved it back. Would the engine flame out, spool down, then automatically relight and spool back up to the same power setting? Or would other adjustments have to be made?

 

[Astro14]

I was going to ask if the control system could be hacked to have this happen remotely or internally. The 10 seconds between switches CUTOFF and ON is curious. Not 9 or 11 seconds but exactly 10 seconds apparently.

I don’t believe it can - various people have talked about “hacking“ airplanes, but all they’ve been able to hack into is the entertainment system.

They’re not connected.

It’s like Battlestar Galactica, there are computers, but they’re not networked, so the cylons can’t break in.

The ability to hack into an airplane, that is, to take control of it, is one of the huge arguments against autonomous airplanes. You have to have a backup system to allow you access to the aircraft controls, in case something went wrong with the aircraft and flight.

Imagine the terrorist possibilities that creates.

 

[Astro14]

Astro, just to be clear on how these cutoff switches work. Say you were cruising at 35,000 ft. hand flying the airplane, and you moved one of these switches to "cutoff". Then waited 30 seconds, and moved it back. Would the engine flame out, spool down, then automatically relight and spool back up to the same power setting? Or would other adjustments have to be made?

The faster you go from “cut off“ back to “run“, the faster the engine will relight and spool back up.

So, in the case of this airplane, the engines have a “auto relight” feature. So do many types of engines. It’s pretty common. In fact, the CF-6 will auto-relight automatically while other types require cycling the switch.

Cycling the fuel control switches from run, to cut off, back to run, starts the relight.

30 seconds is a long time.

Without the pressure of combustion, the RPM on the engine drops pretty low. It depends on the airspeed & altitude of the aircraft, but it’s gonna get down below where it would normally idle.

In that case - the relight might take as long as two minutes. Might be quicker - again, it depends on a lot of factors.

Turbines take a while to get from low speed to operating speed. There is an aerodynamic balance between the high-pressure, and low pressure, spools. Those spools contain both the compressor section, and the turbine section, and they have to be kept in balance as they accelerate.

So there’s a limit on the rate of that acceleration, and therefore on the rate of restart.

Over 40 years ago, a Delta Airlines 767 accidentally shut down both engines while taking off from Los Angeles.

It happened at about 2000 feet, they quickly realized they had cycled (not really bumped) the fuel switches, which was the wrong thing to do, and they put them back in run. The engines re-lit, accelerated, and the airplane flew away.

I am pretty certain that incident caused Boeing to redesign the 767 fuel control system, and place the EEC switches on the overhead, but even back then, it was impossible to “bump“ the fuel control switch.

The crew was responding to a malfunction, and really messed it up.

https://asn.flightsafety.org/wikibase/147073

 

[Jimmy_Russells]

Sort of on topic - I seem to recall I believe a Korean Air 747 crashing a few decades ago from the FO not wanting to correct the Captain as well.