On June 12th, 2025, Air India flight 171 took off from Ahmedabad India enroute to London England with 230 passengers and 12 crew aboard. About 32 seconds into the flight the Boeing 787-8 Dreamliner went down just beyond the end of the runway into some building.
One person, in seat 11A, literally walked away from the crash. The other 241 people on board were killed along with 19 people on the ground.
The tragedy was caught on multiple videos which, following the crash, were dissected in an attempt to determine what may have gone wrong. One clear clue was that the Ram Air Turbine (RAT) had deployed which indicated a possible loss of power. There was also some speculation about the flaps being in the wrong position.
The pilots were both seasoned fliers. The Captain was Sumeet Sabharwal, 56, who had logged approximately 15,600 flight hours, including nearly 8,600 hours on the Boeing 787. The first officer, Clive Kunder, 32, had around 3,400 flight hours, with around 1,100 hours on the Boeing 787.
Now it's been a long time since my FAA days but I figured I would wait for the preliminary report from the Indian government because speculating.
Now the preliminary report has been released and perhaps raises more questions than it answers.
First the What
The cause of the crash was the loss of power in both engines. The flaps were in the proper position and the RAT had indeed been deployed in response to the loss of engine power. The preliminary report listed the following sequence of events from the flight recorder:
08:07:33 UTC - Take-off clearance was issued
08:07:37 UTC - The aircraft started rolling.
08:08:33 UTC - The aircraft hit decision speed V1 and achieved 153 kts.
08:08:35 UTC - The Vr speed of 155 kts was achieved.
08:08:39 UTC - The aircraft lifted off.
08:08:42 UTC - The aircraft achieved the maximum recorded airspeed of 180 Knots.
Then the following quotes are in the report:
"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 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."
"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”.
So, my summary would be:
(1) Both fuel cutoff switches went from run to cutoff in the space of about 1 second.
(2) One pilot (who is not identified in the report) asked the other why he cutoff the fuel and the other pilot replied that he didn't.
(3) About 10 seconds later fuel was restored to engine 1 which began its recovery sequence.
(4) About 4 second later fuel was restored to engine 2 which also began its recovery sequence.
(5) Engine 1 started to recovery but engine 2 was unable to stop deceleration.
The bottom line seems to be that the aircraft was too close to the ground to recover from the fuel cutoff to both engines and crashed.
Now the Why
The preliminary report is clearly incomplete and has led to a host of speculation and additional questions. First the questions.
#1 - Which pilot asked the question about the cutoff and which denied he had done it?
#2 - Were both pilots truly perplexed about the fuel cutoff or was one faking it.
#3 - To turn the fuel switch to cutoff, you have to lift the spring loaded switch, move it and then drop it down. Can a human do that in 1 second or is the time interval in the report wrong?
#4 - Why wait 10 second and then another 4 second to restore fuel to the engines?
I have seen three hypotheses about what happened.
Hypothesis #1 - One person was talking about a chip that, if it failed, could cause fuel to be cutoff to both engines.
This would explain the short time interval between switch changes and the confusion of the pilots. It might also explain the 10 second delay because the switches might appear to still be in the ON position.
I don't buy this one for three reasons. He didn't identify the mysterious chip. No engineer in his right mind would approve a design where a single chip failure could cut off fuel to both engines. If such a chip failed, then how did they restart the engines?
Hypothesis #2 - From the report:
"The FAA issued Special Airworthiness Information Bulletin (SAIB) No. NM-18-33 on December 17, 2018, regarding the potential disengagement of the fuel control switch locking feature."
"The airworthiness concern was not considered an unsafe condition that would warrant airworthiness directive (AD) by the FAA."
From SAIB No. NM-18-33:
"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."
One has to wonder why this was not considered an "unsafe condition?" Of course one also has to wonder why no one had noticed this on this aircraft if the locking mechanism was indeed disengaged? The locks would have been disengaged on previous flights and pilots would certainly have noticed the problem.
So could vibrations during takeoff cause both switches to transition from ON to CUTOFF? That seems unlikely, but so does a human moving both switches in one second if the spring lock is engaged. What about if it's not engaged?
This might resolve the short timeframe between switches changing and the confusion of the pilots but I don't see them waiting 10 seconds to resolve the situation.
Hypothesis #3 - One of the pilot purposely moved the switches and caused the aircraft to crash.
The FO was reportedly flying the plane and both hands would be engaged with the stick and the thruster. Besides, if he wanted to crash the plane he probably could have done so without needing to shut off the fuel. Although he might have has reasons to make the reason for the crash less obvious.
That leaves the Captain. But WHY?
The other mystery is why the 10 second gap between the fuel being cut off and the attempt to restart the engines. I can only think of two reasons, conflict or confusion.
The conflict would be the result of one pilot trying to restore fuel flow and the other trying to stop him.
As for the confusion, I wonder if there is any way in pluperfect hell, other than the chip failure idea, that fuel could have been cut off to both engines, triggering the alarms, even though the switches remained in the ON position. That might have required the switches to be turned to CUTOFF and then back to ON. I would certainly has paused a few seconds if the alarms and the switches were telling different stories.
What do I think
As I said I find Hypothesis #1 highly implausible and I'm not happy with #2 and #3 either. Without a lot more evidence I refuse to believe that either pilot would do such a thing. Perhaps when more information is available, a fourth hypothesis will appear.
