Air India crash

[Reynard]

Tomorrow is the anniversary, and theoretically a ‘final’ investigation report should be forthcoming.  
 

There is skepticism that the final report will provide anything conclusive, or indeed that a report will be issued at all in the expected timeframe.

[onetrack]

The Indian Air Accident Investigation Bureau is obliged to hand down a report on Friday 12th June. It will not be the final report. It will still only be an interim report. This is because the examinations of the engines and electronic systems of the crashed aircraft are still not complete. It will take much longer for a final report - and perhaps even then, there will still be doubt over the conclusions of the investigation.

 

Essentially, the crash boils down to one of two scenarios. One, the Capt threw the fuel cutoff switches to off and then returned them to on, too late to recover. Tim Atkinson, a former British air crash investigator is convinced there is no other cause, but that the Capt threw the engine fuel switches to off - and blames his actions as a homicide-suicide. 

Another Indian investigative journalist is pursuing a line that the switches in the cockpit were never moved, and the engine shutdown was a result of some kind of short circuit in the electronics that shut the fuel off, without the switches in the cockpit being activated. Aircraft manufacturers and designers state the 787 design, absolutely precludes any such possibility.

 

My take is that because around 90% of aircraft accidents are caused by errors on the part of the crew, the law of averages would support the cause of the crash being physical action on the part of the Captain, in throwing the fuel switches to off. To say he did that, in a suicidal moment, is taking things too far, IMO.

I would suggest he threw the fuel switches to off, in a moment of mental confusion/stress/work overload/absentmindedness, without even being aware of doing so, for several seconds. Then when he realised what he'd done, he threw the switches back to on, in a desperate attempt to recover adequate flight speed.

The very best of highly trained people have "Oh, sh**!!" moments, when they make a serious error in equipment operation, especially at critical times. In this case, I believe it was a mental distraction error at the worst possible time, and it was one that was unrecoverable from, due to engine response lag. I believe it's unlikely we'll see a final report, for possibly at least another 12 months.

[pmccarthy]

Apparently the RAT deployed while it was still on the ground, before the switches turned off.

[onetrack]

If that can be proven, then the possibility of the fuel cutoffs being activated without physical movement of the switches in the cockpit increases.

 

But there's two engines, two separate fuel systems, two fuel cutoff switches, and the electrics and hydraulics on each side operate largely independently. It doesn't seem possible that any electrical fault in the aircraft would actuate both fuel cutoff switches. Unless it was a short-circuit that closed both cutoff switch circuits at once.

 

Something crushing the cutoff switch wiring to both switches, so bare wires were shorted, seems the only likely scenario. But that would have to be an intermittent crush, for the cutoff switches to be able to be switched back on again, as the initial report says they were.

[pmccarthy]

Are these hard wired circuits? Or are they mediated by a computer system?

[IBob]

7 hours ago, pmccarthy said:

Apparently the RAT deployed while it was still on the ground, before the switches turned off.

As I recall, the RAT is not armed to deploy until the aircraft is in flight mode...that is, when the weight comes off the undercarriage.
It looks as though that is when the RAT deployed: as soon as the wheels left the ground. Which would indicate that the condition/s to cause the RAT to deploy were present at time of rotation.
 

[facthunter]

Modern jet engines can be started and just go to full throttle. From the CVR and the Voices I am of the view that  the Captain Prevented the FO from moving the switches for long enough to make it too late to save the Aircraft. Maybe he got passed over for a Promotion??  The Airline had just changed Hands.  Nev

[facthunter]

 In Commercial Airlines 35-50% of crashes are crew  error related often just a Judgement. Got too slow etc. Airline crews do a lot of  Full Motion simulator work getting the Abnormals and Emergency actions just right .. That's why flying is the safest way to go. Nev

[onetrack]

PMC - There is mediation by the onboard computerisation in the fuel cutoff switch operation. The fuel valves are spring loaded to the shutoff position to stop fuel-fed fires in the case of a crash.

Placing the fuel cutoff switches in RUN closes the 28V circuit to the fuel valve solenoids, which then overcome the spring-loaded pressure to keep the fuel valves open.

There is mediation in the circuitry by the aircrafts engine EEC's. The systems are exceedingly complex, with the aircrafts Common Core System being the major system that controls all flight parameters.

The following info is useful.

 

https://aviation.stackexchange.com/questions/110989/does-the-fuel-switch-directly-control-the-fuel-valve

 

https://aviation.stackexchange.com/questions/110972/are-cockpit-switches-directly-connected-to-the-fdr-or-are-there-software-hardwa

 

Edited June 12 by onetrack
addendum....

[Garfly]

For me, the suicide theory has never rung true regarding the AI 171 crash.  

But whether you're inclined for or against that explanation, there are several sophisticated arguments out there - on both sides - which do not rely on the timeline and selective CVR quotations set out in the AAIB's Preliminary Report which has been widely regarded as partial and unreliable from the get-go.

 

This recent BBC article is a pretty level headed review of the various theories as they currently stand: 

 

 

The furious dispute over what caused Air India flight 171 to crash

WWW.BBC.COM

---

The final conclusions of the investigation have yet to be published, although more could become apparent in the coming days.

 

Edited June 12 by Garfly

[onetrack]

Of course, the bottom line is - a crash-proof cockpit camera would eliminate all uncertainty around the crash, and tens of millions spent in the investigation, and all the "reputation protection" that is currently going on.

 

We have cameras recording movements of people, both travellers and employees, in public transport vehicles, buses and trains - we have cameras everywhere in public areas, along roads and highways - we have airports full of cameras recording the movements of air travellers and flight crew - yet we cannot install cameras in aircraft cockpits, because vocal and powerful pilots unions, claim the footage will be used against them for relatively minor employment infractions, and to consistently lay blame on them?

 

This is warped decision-making at the highest levels, corrupted by one powerful group. Flight crew hold hundreds of people lives in their hands and actions. Simply install cockpit cameras, and to hell with pilots unreasonable arguments. And address the mental health problems that pilots face with better treatment procedures, and a more enlightened and humane approach.

Serious levels of depression affects many people, even when they don't hold high pressure job positions. 

[Marty_d]

1 hour ago, onetrack said:

Of course, the bottom line is - a crash-proof cockpit camera would eliminate all uncertainty around the crash, and tens of millions spent in the investigation, and all the "reputation protection" that is currently going on.

 

We have cameras recording movements of people, both travellers and employees, in public transport vehicles, buses and trains - we have cameras everywhere in public areas, along roads and highways - we have airports full of cameras recording the movements of air travellers and flight crew - yet we cannot install cameras in aircraft cockpits, because vocal and powerful pilots unions, claim the footage will be used against them for relatively minor employment infractions, and to consistently lay blame on them?

 

This is warped decision-making at the highest levels, corrupted by one powerful group. Flight crew hold hundreds of people lives in their hands and actions. Simply install cockpit cameras, and to hell with pilots unreasonable arguments. And address the mental health problems that pilots face with better treatment procedures, and a more enlightened and humane approach.

Serious levels of depression affects many people, even when they don't hold high pressure job positions. 

The answer to their concerns? Simply delete the flight's cockpit video recording when the plane is safely stopped at the gate. That way it can't be used for anything except serious incident analysis.

[BurnieM]

The problem of course is that worksite cameras have been misused to take disciplinary action against many workers, often to avoid paying out termination payments. So you have a biased pilot union fighting a very cost based management.

 

The suicide theory appears to imply that Indian pilots do not feel a moral obligation to protect passengers in their charge and seek to harm the company. I believe this is the opposite of how most western pilots think/feel. Is this what you are implying ?

 

[onetrack]

No, I'm not implying that at all, and I stated I don't believe that the crash was a deliberate suicide, and I believe more likely to be a simple human error.

[Thruster88]

15 hours ago, pmccarthy said:

Apparently the RAT deployed while it was still on the ground, before the switches turned off.

It is worth re reading the preliminary report.  The CVR will hear things like switch movements. I feel there would have been more said on the CVR than was put in the preliminary report.

 

Part of the preliminary report below.

 

As per the EAFR data, the aircraft crossed the take-off decision speed V1 and achieved 153 kts IAS at 08:08:33 UTC. The Vr speed (155 kts) was achieved as per the EAFR at 08:08:35 UTC. The aircraft air/ground sensors transitioned to air mode, consistent with liftoff at 08:08:39 UTC.  

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. 

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.  

The CCTV footage obtained from the airport showed Ram Air Turbine (RAT) getting deployed during the initial climb immediately after lift-off. No significant bird activity is observed in the vicinity of the flight path. The aircraft started to lose altitude before crossing the airport perimeter wall.

As per the EAFR data both engines N2 values passed below minimum idle speed, and the RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC. 

As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.  

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. The EAFR recording stopped at 08:09:11 UTC 

At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”. The ATCO enquired about the call sign. ATCO did not get any response but observed the aircraft crashing outside the airport boundary and activated the emergency response. 

At 08:14:44 UTC, Crash Fire Tender left the airport premises for Rescue and firefighting. They were joined by Fire and Rescue services of Local Administration. 

Accident involving Air India’s B787-8 aircraft bearing registration VT-ANB at Ahmedabad on 12 June 2025

[onetrack]

The 12 month deadline has passed, and no new investigation results have been released. However, the Indian AAIB released a short statement, claiming they need more time to produce the final report.

I saw an interview with the woman head of the Indian Air Cargo Federation, and she claims the final report is unlikely to be produced until September 2026 at the earliest - and even then, there will no doubt be claims that the investigation is deficient, and it will lead to renewed and further lawsuits.

 

Here is the IAAIB statement, released on 12th June 2026 -

 

https://aaib.gov.in/What's New Assets/AAIB Interim Statement.pdf

 

One of the interesting points that came out of the interview with the IACF head, was that over 300 new airports will be opened in India this year and the Indians are very focussed on ensuring that their aviation safety standards are kept up to a high level. That is a staggering upsurge in Indian aviation activity.

 

Edited Saturday at 01:07 AM by onetrack
addendum...