This is an update with fresh evidence and arguments to my article Air India Crash: When 2 + 2 Does Not Compute .
The "smoke" at liftoff
The plume is almost certainly dust lifted by turbulent wake, a force which has been powerful enough to down tailgating aircraft. Ahmedabad suffers from heavy air pollution, much of which settles eventually as dust. As planes take off and disturb the dust there will be less and less dust to disturb. The dust will only be visible again in the wake of a plane that has taken even slightly longer than others to acheive liftoff. Other than the possibility of a slightly overlong takeoff run, the dust is not evidence of any serious malfunction in the plane.
FADEC thrust control error?
The TCMA / FADEC system may have cut the fuel just before or after liftoff. The bypass fans would still deliver 80% TOGA thrust at that point, gradually tapering off. During the takeoff run the pilots will be highly focused on: ground speed, speed check points, maintaining runway centre-line, runway distance remaining. The PM - Pilot Monitoring will also be checking engine data. After liftoff the failure of the hydraulics to raise landing gear would be an instant alert. With multiple alarms once airborne the pilots' first indication of fuel cutoff would likely have been a feeling of rapidly declining acceleration. The surviving passenger reported the feeling of the plane stopping, which is consistent with loss of acceleration. This declining acceleration would prompt the pilots to look at the instrument panel and see a fuel cutoff alert.
The AAIB preliminary report gives a maximum speed - Vmax - of 180 knots. If that Vmax value is accurate then it would indicate thrust in excess of 100% in the not-clean configuration. The FADEC program will not permit more than 100% thrust. It will treat over 100% thrust as an engine fault and will shut off fuel.
Phantom thrust
High-bypass turbofan engines have a slower RPM decline than a traditional turbojet due to the fan's diameter. The rpm decline at fuel shut off will be lower as the air density reduces.
The 787's high bypass ratio engines will continue to deliver thrust after fuel shutoff. The spool-down rate will increase with reducing rpm. Thrust at fuel shutoff from TOGA setting is about 80%. The pilots should feel an almost instantaneous 20% or more drop in thrust as a drop in acceleration. This will prompt the pilot monitoring to look at the engine parameters and notice the fuel cutoff.
AAIB interim report extract1
Lost in mistranslation?
This reported speech is ambiguous in many ways: "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.". If, as is likely, the spoken words were in Hindi then the first 'he' could mean the plane and the second 'he' could mean the pilot who is responding.
Pilot #1 asks rhetorically why s/he (the plane) cut off. In Hindi.
Pliot #2 responds "I didn't do so." In Hindi.
But the world at large treats this snippet of report speech as if it were a question and answer spoken in English.
Cherry-picking par excellence
The AAIB reported speech appears to rely on superficial plausibility to support the pilot error/malice narrative.
At the fuel cutoff recognition point one of the pilots will, per memory items, move the fuel switch to cutoff and then to run. He will then, most likely, check the panel to see if the fuel to that engine is restored and the relight sequence has started. He will then repeat this for the other engine. This would explain why one engine began to provide some thrust while the other, likely the second to be triggered for relight, did not.
Any prior electrical fault, plus spooling down of the engines' generators will lead to loss of the hydraulic power which is provided by electric pumps on the 787. The OR fault logic for the RAT includes loss of hydraulic power OR loss of both engines' thrust. From command of RAT deployment to the raising of full hydraulic pressure takes 6 to 7 seconds and 10 seconds from deployment to full electric power2.
The AAIB report does not state the time at which the RAT deployed.
Systemic Decay - When New Stuff Breaks Old Stuff.
The topic of systemic decay needs to be covered in a separate article. In brief, systemic decay is the gradual failue of any electronic, mechanical, biological or human system as time goes by. For now, here's an example: putting a new starter on a car can trigger failure of an old battery. The cause of the failure is that the new starter can draw higher current than the one it replaced. The lead-acid battery will have already suffered systemic decay in its internal structure and chemical composition. The sudden increase in current flow is likely to induce battery failure quite soon, in the proverbial camel and straw scenario.
Replacement of any type of component in any type of system can lead to instability at least, and system failure at worst. Systems being repaired or modified must be checked to ensure that new components will play nice with old components. This also applies where humans are the components of a system.
Systemic decay is inevitable
A history of reliablity is no guarantee of continuing reliability. For instance let us say that plane X has crashed. Many examples of plane X have been flying for ten years now without crashing. Ipso facto the pilots must have done something wrong. This specious argument completely ignores the "ipso facto" of systemic decay.
Systemic decay and maintenance
With systemic decay comes the inevitable and ever-growing burden of maintenance and repair. Where planes are concerned the highest standards of maintenance must be observed.
"... while the cause of the crash in June has yet to be confirmed, it has already proved damaging for Air India and Tata, shaking consumer confidence and shining a light on a series of operational challenges and mishaps involving their aircraft."
Air India under growing pressure as safety record scrutinised after deadly crash , The Guardian3 29 July 2025
Sources
1 - AAIB Preliminary Report
https://aaib.gov.in/What's%20New%20Assets/Preliminary%20Report%20VT-ANB.pdf
2 - Air India Crash - RAT Questions
https://www.youtube.com/watch?v=gsYf_SRyCtg
3 - Air India under growing pressure as safety record scrutinised after deadly crash
https://www.theguardian.com/world/2025/jul/29/air-india-plane-crash-ai17...
Any further updates will be linked here.
edit update links added
Air India Crash: When 2 + 2 Does Not Compute
Air India Crash: Update #1
Air India Crash: Update #2 - The AAIB Report Revisited
Air India Crash: Update #3
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