Air India Flight to Gatwick crash - unconfirmed 242 on board

[madlad7773]

Yeah, this is very odd.

Apparently on the CVR (Cockpit voice recorder), one of them said "why did you do the cut off" and the other one said "I didn't".

Some weird reports here, some say the switches were found in the off position, and some say they were cycled off and back on. They must have been back on, as the engines had started to spool up again, and one of them was already producing thrust when it crashed.
I don't care what the reports say, when they say "it's almost impossible to move both switches at the same time", if they did have the detent fitted, this is a myth. When you're flicking these switches every day (and there are loads like this) you get really good at overriding features like this one handed, without even thinking about it, if they're close together. Whether these detents were fitted or not doesn't really make a difference to whether it was one handed or two handed, can be done either way. Obv operating two switches with two hands is really obvious and the other pilot would ask questions. You could flick one after the other one handed too, which would be less noticeable, but as soon as you flick that switch the fuel cuts immediately and within a couple of seconds you would get all sorts of warnings as well as notice the sound changes.

If the detents were fitted though, then it would be tough to flick those switches to off by accident, as in moving your hand near there (not flicking the wrong switch). It's not like they would have throttled back (closest thing to the switches) and accidently flicked them off doing that, or moved the flaps back again (also close). The flaps will have already been set, pulled back a bit (and later pushed forward) and the throttles pushed forward where they stay. There's no real reason to be operating anything in that area so soon after take off, so accidental turn off by knocking it with something seems unlikely to me.

My best guesses are (in order of likelihood)
1 - One of them has flicked both switches by accident, when they've gone to change something else which has a detent, maybe the landing gear lever, and they've not even known they've done it. It was a pretty early flight, they could have been tired etc.
2 - Something has caught on or knocked both switches and flicked them both at the same time, this is possible and much more likely without the detent
3 - One of them has had a melt down and switched them off intentionally, but this seems unlikely as the pilots were doing maydays and trying to get them going again (maybe the one who said, "I didn't" just had a bit or regret/ didn't want to admit it?).
4 - Some sort of mad electrical fault has moved the switch on it's own, some switches can do this, but I don't think these can
5 - Someone else flicked the switches? Was anyone else in the cockpit who shouldn't have been there?

Having done some work back in the day with the AAIB, and coming from an aviation background, working for an airline and studying air accidents in some detail, I think what's happened is the switches were on (you can't push back without them being on for taxiing plus its in a mandatory departure checklist to do) but there was an electrical issue on the take off run which has tripped the switches to off. This shouldn't be allowed to happen, but is linked into the findings of that report mentioned from a few years earlier on B737s. Now, if that's what's happened, and looking at what we know, the aircraft lost power on rotation, a mayday was called, the CVR excerpts and also the RAT deployment, plus the gear still being down, this may suggest a wider electrical issue with the 787. If it is that, then that earlier report should be turned into an airworthiness directive making sure it's resolved. Otherwise, each time a B737-8 or a B787 operate, this failure could happen at any time. Effectively, the electrical issues fooled the aircraft into thinking it was shut down at the gate and master switch tripped the engines. That would explain the fuel cut off, the flaps/slats not being at 15, the RAT deploying, the gear not retracting but also you see in one of the videos as one of the engines spools back up, the nose of the aircraft pitches ever so slightly up. If it had been at 1000-1300 ft, I think the one engine would have carried it clear to climb, get to 5000ft, assess the situation and return to the airport. It would have had to dump full though out over the bay. Factor in the video showing the previous flight where the IFE, intercoms and lights were going haywire, and I reckon this is 100% an aircraft electrical fault. The question is more..is this an Air India maintenance issue or is this a fleet wide known problem? I guess it'll all come out soon.

 

[ForssAwakens]

Having done some work back in the day with the AAIB, and coming from an aviation background, working for an airline and studying air accidents in some detail, I think what's happened is the switches were on (you can't push back without them being on for taxiing plus its in a mandatory departure checklist to do) but there was an electrical issue on the take off run which has tripped the switches to off. This shouldn't be allowed to happen, but is linked into the findings of that report mentioned from a few years earlier on B737s. Now, if that's what's happened, and looking at what we know, the aircraft lost power on rotation, a mayday was called, the CVR excerpts and also the RAT deployment, plus the gear still being down, this may suggest a wider electrical issue with the 787. If it is that, then that earlier report should be turned into an airworthiness directive making sure it's resolved. Otherwise, each time a B737-8 or a B787 operate, this failure could happen at any time. Effectively, the electrical issues fooled the aircraft into thinking it was shut down at the gate and master switch tripped the engines. That would explain the fuel cut off, the flaps/slats not being at 15, the RAT deploying, the gear not retracting but also you see in one of the videos as one of the engines spools back up, the nose of the aircraft pitches ever so slightly up. If it had been at 1000-1300 ft, I think the one engine would have carried it clear to climb, get to 5000ft, assess the situation and return to the airport. It would have had to dump full though out over the bay. Factor in the video showing the previous flight where the IFE, intercoms and lights were going haywire, and I reckon this is 100% an aircraft electrical fault. The question is more..is this an Air India maintenance issue or is this a fleet wide known problem? I guess it'll all come out soon.

Can an electrical problem, trip the fuel cutoff switches when the lock is disengaged?

And if it was tripped why did it record 1 second apart

 

[madlad7773]

Can an electrical problem, trip the fuel cutoff switches when the lock is disengaged?

And if it was tripped why did it record 1 second apart

It shouldn't happen. There's meant to be a failsafe dating back about 40 years to stop it happening but with the advent of more computer control, fly by wire and so on, it's not a stretch to think it could have happened.

Looking at it logically, none of the following should have happened:
1. Flaps/slats in the wrong position (departure check list)
2. Engines on, not off. The aircraft disconnects from the APU on start up so the engines should be turning and in order to even start the take off roll so we know they were on
3. Gear still down that long after rotation.
4. Ram air turbine deployment directly after rotation
5. Aircraft using full runway right to the threshold. (The dust churned up on climb out) This would only happen usually if the flight is extremely heavy at max TO weight.

Normal take off:

Engine start, disconnect APU, checklist,ground confirm pushback, taxi to runway threshold,clearance,start roll, V1,rotation,V2, positive climb,gear up (the time from rotate,climb,gear up should be done by around 600ft latest)

Just looking at both videos, knowing what we know, I can't imagine a rested crew would reach back and cut the fuel on the engines knowingly, especially at a flight critical time on the runway. That leaves either Air India maintenance/checks issue or a fleet wide Boeing issue with both B737 & 787s. If the latter is the case, expect a lot of grounded aircraft while the issue is sorted. Usually an accident doesn't happen if you stop one part of the chain of events from happening.
Also worth remembering a grain of sand can bring down a large airliner. Reassuringly,it remains the safest form of transport by some distance. I think the stats are something like you'd have to get on a flight every day 26,000 times before you had any form of emergency and even then, it's likely survivable.

 

[ThePrisoner]

Having done some work back in the day with the AAIB, and coming from an aviation background, working for an airline and studying air accidents in some detail, I think what's happened is the switches were on (you can't push back without them being on for taxiing plus its in a mandatory departure checklist to do) but there was an electrical issue on the take off run which has tripped the switches to off. This shouldn't be allowed to happen, but is linked into the findings of that report mentioned from a few years earlier on B737s. Now, if that's what's happened, and looking at what we know, the aircraft lost power on rotation, a mayday was called, the CVR excerpts and also the RAT deployment, plus the gear still being down, this may suggest a wider electrical issue with the 787. If it is that, then that earlier report should be turned into an airworthiness directive making sure it's resolved. Otherwise, each time a B737-8 or a B787 operate, this failure could happen at any time. Effectively, the electrical issues fooled the aircraft into thinking it was shut down at the gate and master switch tripped the engines. That would explain the fuel cut off, the flaps/slats not being at 15, the RAT deploying, the gear not retracting but also you see in one of the videos as one of the engines spools back up, the nose of the aircraft pitches ever so slightly up. If it had been at 1000-1300 ft, I think the one engine would have carried it clear to climb, get to 5000ft, assess the situation and return to the airport. It would have had to dump full though out over the bay. Factor in the video showing the previous flight where the IFE, intercoms and lights were going haywire, and I reckon this is 100% an aircraft electrical fault. The question is more..is this an Air India maintenance issue or is this a fleet wide known problem? I guess it'll all come out soon.

The preliminary report doesn't mention an electrical issue or call for any remedial action or grounding of other aircraft though, does it?

Maybe one of the pilots turned the switches off by mistake, while thinking he was doing some other operation?

 

[ForssAwakens]

It shouldn't happen. There's meant to be a failsafe dating back about 40 years to stop it happening but with the advent of more computer control, fly by wire and so on, it's not a stretch to think it could have happened.

Looking at it logically, none of the following should have happened:
1. Flaps/slats in the wrong position (departure check list)
2. Engines on, not off. The aircraft disconnects from the APU on start up so the engines should be turning and in order to even start the take off roll so we know they were on
3. Gear still down that long after rotation.
4. Ram air turbine deployment directly after rotation
5. Aircraft using full runway right to the threshold. (The dust churned up on climb out) This would only happen usually if the flight is extremely heavy at max TO weight.

Normal take off:

Engine start, disconnect APU, checklist,ground confirm pushback, taxi to runway threshold,clearance,start roll, V1,rotation,V2, positive climb,gear up (the time from rotate,climb,gear up should be done by around 600ft latest)

Just looking at both videos, knowing what we know, I can't imagine a rested crew would reach back and cut the fuel on the engines knowingly, especially at a flight critical time on the runway. That leaves either Air India maintenance/checks issue or a fleet wide Boeing issue with both B737 & 787s. If the latter is the case, expect a lot of grounded aircraft while the issue is sorted. Usually an accident doesn't happen if you stop one part of the chain of events from happening.
Also worth remembering a grain of sand can bring down a large airliner. Reassuringly,it remains the safest form of transport by some distance. I think the stats are something like you'd have to get on a flight every day 26,000 times before you had any form of emergency and even then, it's likely survivable.

I thought the flaps have been confirmed as being in the right position now?

It also feasible the landing gear would have been left out longer particularly if it was a long take off. Plus it didn’t get over 600ft

The crew were rested not overworked

You also didn’t explain how if it was a trip the 1 second apart

 

[ForssAwakens]

The preliminary report doesn't mention an electrical issue or call for any remedial action or grounding of other aircraft though, does it?

Maybe one of the pilots turned the switches off by mistake, while thinking he was doing some other operation?

Given the position of the switches I believe it would be highly unlikely

 

[madlad7773]

I thought the flaps have been confirmed as being in the right position now?

It also feasible the landing gear would have been left out longer particularly if it was a long take off. Plus it didn’t get over 600ft

The crew were rested not overworked

The gear should be up after V2 and positive climb. All under 450ft usually. The only reason the gear would be down is either an electrical/hydraulic issue or the workload in the flight deck was in overload. In truth, both were probably true. But if there wasn't an electrical issue, the RAT wouldn't have deployed. Simple as that. Also, if the flaps were set at 15 as per take off roll, if the electrical fail happened towards the rotation point, they could have retracted by themselves if the hydraulics or electrics had failed.

 

[ForssAwakens]

The gear should be up after V2 and positive climb. All under 450ft usually. The only reason the gear would be down is either an electrical/hydraulic issue or the workload in the flight deck was in overload. In truth, both were probably true. But if there wasn't an electrical issue, the RAT wouldn't have deployed. Simple as that. Also, if the flaps were set at 15 as per take off roll, if the electrical fail happened towards the rotation point, they could have retracted by themselves if the hydraulics or electrics had failed.

What about the 1 second apart that you attributed the switches flicking, surely the both trip at the same time

 

[ThePrisoner]

Given the position of the switches I believe it would be highly unlikely

If the electrical failure theory has merit then surely warnings should be given to aircraft operators?

Boeing shares would be worth pennies.

 

[madlad7773]

According to the report, the shut down happened in sequence so basically this, as much as it can I suppose, explains some of it:

"The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08 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. "

 

[madlad7773]

If the electrical failure theory has merit then surely warnings should be given to aircraft operators?

Boeing shares would be worth pennies.

Guidance was given a few years ago as per B737s but it was not deemed urgent, no airworthiness directive was issued by the FAA.

 

[goalscrounger]

Apologies for the triviality of this comment, but it never ceases to amaze me the depth and breadth of knowledge on what is nominally a forum for supporters of a medium sized Championship football team in the north east of England. This thread has made for fascinating reading, thank you to all those adding their expertise here.

 

[madlad7773]

We all have different interests, from different backgrounds and Middlesbrough FC unites us. I love this forum.

 

[ThePrisoner]

According to the report, the shut down happened in sequence so basically this, as much as it can I suppose, explains some of it:

"The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08 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. "

Do the fuel switches and engines have independent electrical supplies?

Did electricity fail because the engines were both turned off rather than the other way around?

Does all electricity fail or is there battery back-up for some systems as well as the RAM and the APU (which seems to have at least begun to deploy as it's air inlet was open).

 

[chickenrunner]

The offending switches appear to be toggle switches with a detent not circuit breakers i.e. there is no electrical actuation of the switches. Nominally it would require someone to physically operate them.
However the question would be how does the flight recorder determine the position of the switches. I would imagine this is by monitoring the supply FROM the switches. Is it possible that the supply TO the switches was lost rather than the switches being operated? Did the flying pilot receive an indication that the switches had been operated prompting him to question the other pilot who simply confirmed he hadn't touched them?

 

[Ingleby_Flash]

The offending switches appear to be toggle switches with a detent not circuit breakers i.e. there is no electrical actuation of the switches. Nominally it would require someone to physically operate them.
However the question would be how does the flight recorder determine the position of the switches. I would imagine this is by monitoring the supply FROM the switches. Is it possible that the supply TO the switches was lost rather than the switches being operated? Did the flying pilot receive an indication that the switches had been operated prompting him to question the other pilot who simply confirmed he hadn't touched them?

This sounds feasible, know nowt about planes, but a bit about control systems and in a modern plane like this I would guess (just an educated guess) they probably sent a signal to a control system rather than doing an actual isolation. In which case the electrical problems they appeared to be having already are probably the root cause.

 

[Soutra]

Having done some work back in the day with the AAIB, and coming from an aviation background, working for an airline and studying air accidents in some detail, I think what's happened is the switches were on (you can't push back without them being on for taxiing plus its in a mandatory departure checklist to do) but there was an electrical issue on the take off run which has tripped the switches to off. This shouldn't be allowed to happen, but is linked into the findings of that report mentioned from a few years earlier on B737s. Now, if that's what's happened, and looking at what we know, the aircraft lost power on rotation, a mayday was called, the CVR excerpts and also the RAT deployment, plus the gear still being down, this may suggest a wider electrical issue with the 787. If it is that, then that earlier report should be turned into an airworthiness directive making sure it's resolved. Otherwise, each time a B737-8 or a B787 operate, this failure could happen at any time. Effectively, the electrical issues fooled the aircraft into thinking it was shut down at the gate and master switch tripped the engines. That would explain the fuel cut off, the flaps/slats not being at 15, the RAT deploying, the gear not retracting but also you see in one of the videos as one of the engines spools back up, the nose of the aircraft pitches ever so slightly up. If it had been at 1000-1300 ft, I think the one engine would have carried it clear to climb, get to 5000ft, assess the situation and return to the airport. It would have had to dump full though out over the bay. Factor in the video showing the previous flight where the IFE, intercoms and lights were going haywire, and I reckon this is 100% an aircraft electrical fault. The question is more..is this an Air India maintenance issue or is this a fleet wide known problem? I guess it'll all come out soon.

This is entirely, utterly and completely speculation.

We shouldn't speculate about what happened, but if we are going to speculate then it would appear - overwhelmingly - that the captain turned off the fuel switches.

 

[SydneyRed]

Really? There's no hint of any mechanical failure, or anything that would have caused the switches to move by themselves. I think it's implicit in the report that one or other of the pilots moved the switches.

The Special Airworthiness Information Bulletin referred to in the report, of an issue that has been reported in 737's, could theoretically have led to a situation where the switches were not locked in place and so could have become easier to move by accident but again, for that to happen on a 787 where it has never been reported and with both switches - not simultaneously, but one after another with a slight delay in between, seems highly unlikely.

The guards either side mean you have to deliberately move your hand ibto the right posotu9n to initiate the unlock uplift pre switch change

I know how they work, I've operated these switches with the detents and without thousands of times. I was an aircraft engineer (Avionics), operating, testing and replacing these switches/ control units etc was part of my trade.

The guards look more like side shields, and doesn't look like it would do much, it's not like a weapons release or a crash switch or whatever which has an actual cover.

Some of the questions where whether they had the detents or not, but yeah, inadvertent operation is unlikely with the detents but still not impossible, I've seen it done! People have pulled ejection seat handles by accident.

Yes, they're mechanical switches, but some aircraft have the ability to move mechanical switches (I don't think this does for these switches, which is why I said so). I can't think of any which move switches with detents (but it's been a while).

Of course another person operating the switches without the pilots realising is highly unlikely, but they are in the centre console, to the side of the pilot and copilot, they could be out of vision. They throttles are around where a gear stick is on a car, and the switches rearward of that. Can you see the gear stick when you're looking out the front window?

If someone was low they could maybe get at them, but yeah exceptionally unlikely, would be awkward ot do with the detents from that angle though. Obviously if the cockpit is locked and there's nobody else in there then it's impossible. There are other seats in the Dreamliner cockpit though, behind the pilot, inside the locked door. If there's a time where those switches could get flicked without either noticing, then it's on takeoff (or landing).

Cheers Andy...can see you have good knowledge on this issue, interesting read

 

[madlad7773]

This is entirely, utterly and completely speculation.

We shouldn't speculate about what happened, but if we are going to speculate then it would appear - overwhelmingly - that the captain turned off the fuel switches.

The good thing about this forum is everyone is entitled to their own opinion. I won't shout yours down though. I can only offer an opinion based on my 36 years in aviation.Ive also tried to apply reasons as to why it's very unlikely (not impossible) that it was deliberate and explained them in detail.

 

[exeterboro]

The good thing about this forum is everyone is entitled to their own opinion. I won't shout yours down though. I can only offer an opinion based on my 36 years in aviation.Ive also tried to apply reasons as to why it's very unlikely (not impossible) that it was deliberate and explained them in detail.

The good thing about this forum is that the knowledge is so diverse on it, issues like this allow me through other posters eyes to get a deeper insight into some subjects,, ironically the one thing we do speculate and offer opinion up.on which we don't have a clue is football.