Aircraft Accident Investigation Bureau (AAIB) of India released its preliminary report barely in time. The Air India's B787-8 aircraft bearing registration VT-ANB had crashed in Meghaninagar, less than 1.5 Km from the Ahmedabad Airport on 12-Jun-25.
A preliminary report is required to be released within 30 days and AAIB released one on Saturday, 12-Jul-25 past mid-night. The 15-page report was unsigned - there was no press briefing.
It's 14 pages contain almost useless information, lot of pictures and descriptions which were all known to everyone following the story. The article 12 has critical but truncated information, and information which is undoubtedly available with AAIB but has been withheld has created doubts about pilots' behaviour. One wonders why AAIB took the maximum time allowed to it for releasing the few facts it did in its preliminary report. Perhaps the time it took was for word-smithing and determining which time-stamps of events to hide and which to publish.
The report seems to give a clean chit to Boeing and GE as it says, there are no recommendations to be made to these companies. Yet AAIB says, its preliminary report is not for apportioning blame (as if absolving parties of blame means something else)!
From the time plane starts rolling for takeoff it took 1Minute:34Seconds to crash. It became air-borne in 1M:02S, therefore, it was in the air for 0M:32S only. A second by second account could have been easily provided in one page with maximum of 32 lines in double space.
The following table lists the notable events after takeoff for Air India Flight AI-171, based exclusively on the AAIB preliminary report (article 12). Times are relative to the start of the takeoff roll at 08:07:37 UTC on June 12, 2025.
Time (MM:SS) | Event |
|---|---|
00:00 | Aircraft starts takeoff roll (08:07:37 UTC). |
01:02 | Aircraft reaches 155 knots, air/ground sensors transition to air mode, consistent with liftoff (08:08:39 UTC). |
01:05 | Engine 1 fuel cutoff switch transitions from RUN to CUTOFF (08:08:42 UTC). |
01:06 | Engine 2 fuel cutoff switch transitions from RUN to CUTOFF (08:08:43 UTC). |
? | Pilot conversation: One pilot asks, “Why did you cut off?” Other responds, “I did not do so.” (No exact time specified). |
? | Ram Air Turbine (RAT) deploys, indicating dual engine failure (No exact time specified). |
01:15 | Engine 1 fuel switch transitions from CUTOFF to RUN, initiating relight (08:08:52 UTC). |
01:17 | Engine 2 fuel switch transitions from CUTOFF to RUN, initiating relight (08:08:54 UTC). |
01:28 | MAYDAY call issued by pilots (08:09:05 UTC) - mentioned in article 10 on page 12 |
01:34 | Flight data recorder stops, aircraft crashes (08:09:11 UTC). |
In article no. 4 Aircraft Information, on page 5&6 of the AAIB's report, there is nothing that would draw any suspicion to an improper or insufficient maintenance performed or any known defect or deficiency in the particular plane. Were there any prior incidents of dual engine shutdown? AAIB failed to ask or answer this question? In this section, AAIB did cite one non-mandatory advisory issued by FAA (Federal Aviation Authority of USA): Special Airworthiness Information Bulletin (SAIB) No. NM-18-33 on
December 17, 2018, regarding the potential disengagement of the fuel control switch locking
feature. Air India confirmed that it did not carry out checks on fuel control switch as they were advisory in nature and not mandatory.
The above account would leave the cause of the accident to be explored in
i) the design and performance of the plane manufactured by Boeing,
ii) the design and performance of the engines made by GE and
iii) the conduct of the Air India pilots.
Performance of the plane ought to have included performance of the software or a system malfunction which can occur due to a bug or malware introduced by a saboteur. But this possibility is not cited anywhere in the AAIB report.
AAIB's report, going further, gave almost a clean chit to Boeing and GE by saying that at this time, it had no recommendations to offer to Boeing or GE. It was less equivocal with respect to the conduct of the pilots. After reading AAIB's report more people think Pilots are responsible for the crash than Boeing and hardly anyone blames GE. AAIB has been proclaiming that the preliminary report is not a final report and people should not jump to conclusions. However, AAIB's report is a dead give away of its incompetence and susceptibility to extraneus pressures.
Captain Sumeet Sabharwal, designated as PM (Pilot Monitoring the flight) and First Officer Kunder Clive designated as PF (Pilot Flying the plane) in the context of flight AI-171 were, between them, above average pilots' crew because the former had logged flying time of 15,638:22 Hrs and the latter 3,403:12 Hrs. The former held ATPL (Airline Transport Pilot License) - which is the highest rated commercial Pilot License and he had been Air India's flight instructor too.
Curiously, in AAIB report - many events' time stamp hidden, Pilots' conversation truncated and identity hidden, full transcript and audio alarms going off, if at all, not disclosed, simple Question not posed to Boeing: Can the 787-8B's system CUTOFF fuel to the engines without manual operation of fuel control switches or without physical movement of fuel control switches? Most importantly, The AAIB chose not to disclose the transcripts and descriptions of voices and sounds in the 32 seconds the plane was airborne - did the two pilots work in concert or did they have disagreements in the specific actions they took after they discovered the emergency (loss of dual engines)? Other than the question one pilot asked, what other indicators of dual engine shutdown (or loss of thrust) were there and when did they occur? AAIB has given a miss to this information in its preliminary report.
Both pilots, reportedly have adequate or above average relevant flyig experience. They have an unblemished mental health record. The chances of their acting in concert to deliberately crash the plane, in a fit of suicidal-cum-murderous frenzy, are far less than the chances of a simultaneous dual engine failure which is calculated by many as less than 1 in one billion.
Suppose only one pilot had gone berserk and the other was in a sane state, in such a case they would not act in concert. The Cockpit Voice Recorder would have been definitely processed by the AAIB. If the pilots did not work in concert, there would have been an altercation between them. The chances that officers involved in the AAIB's report preparation, from foreign agencies, particularly from Boeing, would not publish any incriminating conversation between the two pilots can be certainly ruled out. After all the Boeing and GE companies are interested in clearing their name ASAP. [As per AAIB, Officers involved were: "NTSB, USA appointed an Accredited Representative and Technical Advisers from Boeing,
GE and the Federal Aviation Administration (FAA) to assist in this Investigation. A team led
by the NTSB Accredited Representative comprising of representatives from Boeing, GE and
FAA arrived at Ahmedabad on 15.06.2025 and participated in the Investigation. A team of
officials from AAIB, UK also arrived at Ahmedabad and visited the site with DG, AAIB."] See motivations to blame pilots - short clip
Common sense indicates that this accident is not caused by one or both pilots' deliberate actions to cut off fuel supply to engines - it would be simpler or easier to just nose dive rather than cut fuel supply and then try to restore the same all the while keeping the nose of the plane up - videos show the plane's attitude as it sinks from its peak height of four-hundred and odd feet above the ground level - AAIB report also has a diagram that shows 8 degrees upward inclination at the time of crash. Likely, there was a malfunction and the dual engine failure occured for reasons other than the fuel control switch moving from RUN to CUTOFF.
It is reported, the two switches "transitioned" from RUN to CUTOFF after 3 seconds of takeoff with one second interval. The transition events are picked up from the Enhanced Airborne Flight Recorders (EAFR), which also record cockpit voices (there are two EAFRs one in the front and second in the rear of the aircraft).
Let's consider two scenarios of system malfunction in which pilots are heros rather than villains:
A) It is possible that immediately after takeoff the plane suffered a dual engine loss owing to an unknown system failure and the pilots sensed it at once. They quickly decided after seeing the fuel switches in the RUN state that there was something amiss. They figured there was a need to recycle - i.e. reset. As per Boeing's manual for achieving fuel flow revival, in case of dual engine failure, requires exactly the type of recycling actions the pilots took - move the switches from RUN to CUTOFF and then back again from CUTOFF to RUN. See the videos at these links made by an experienced Captain of a Domestic Carrier - Gaurav Taneja (X reference @flyingbeast320): Part-1 Part-2 and Part-3.
B) It is possible that three seconds after takeoff, due to a system malfunction, even without anyone touching the fuel control flow switches, the fuel supply was cut off and the plane suffered a dual engine loss. The pilot who got alerted to the dual engine loss first, asked the other "Why did you cut off"?, to which the other responded, "I did not do so". In this scenario, it is possible the system shifted the switches from RUN to CUTOFF or it is possible that it did not shift the switches but sent a signal for recording in EFAR that the switch had transitioned and it cutoff fuel supply or reduced it drastically to both engines.
There was such a precedent in flight NH985 (from Tokyo to Osaka) just before touch down. KJM Today article has the details - dual engine shutdown occurred through system command, without manual operation of any switches. See also what Mary Schiavo, an Aviation Expert Lawyer has to say here (The Guardian article) and here (Mojo Video).
Summary and Conclusion:
i) the design and performance of the plane manufactured by Boeing,
ii) the design and performance of the engines made by GE and
iii) the conduct of the Air India pilots.
There was such a precedent in flight NH985 (from Tokyo to Osaka) just before touch down. KJM Today article has the details - dual engine shutdown occurred through system command, without manual operation of any switches. See also what Mary Schiavo, an Aviation Expert Lawyer has to say here (The Guardian article) and here (Mojo Video).
Revised Chronology of Events for AI-171
The table below lists the events from takeoff to crash (08:07:37 to 08:09:11 UTC, 1 minute and 34 seconds), integrating my hypothetical scenario#1 with AAIB-reported events. Times are relative to the takeoff roll start (08:07:37 UTC = 00:00), with absolute UTC times provided. Hypothetical events are marked as such, and AAIB-reported events are noted for clarity. The remarks column distinguishes the source of each event.
Time (MM:SS) Event Remarks 00:00 Aircraft starts takeoff roll. AAIB-reported: Takeoff roll begins at 08:07:37 UTC. 01:02 Aircraft reaches 155 knots, air/ground sensors transition to air mode, consistent with liftoff. AAIB-reported: Liftoff at 08:08:39 UTC. 01:03 System malfunction reduces or cuts off fuel flow to both engines, triggering EICAS warnings and/or audible alarms (e.g., “ENGINE FAIL”). Commanding pilot (First Officer) detects dual engine thrust loss. Hypothetical: Assumes system (e.g., FADEC/TCMA) malfunction causes thrust loss one second after takeoff, as per my scenario. Alerts align with standard 787 cockpit warnings. 01:04 Commanding pilot asks, “Why did you cut off?” Other pilot responds, “I didn’t.” Pilots observe fuel control switches in RUN position despite thrust loss. Hypothetical: Places CVR conversation one second after thrust loss detection, consistent with pilot confusion noted in AAIB report. AAIB confirms conversation but provides no timestamp. 01:05 Engine 1 fuel cutoff switch transitions from RUN to CUTOFF. AAIB-reported: Switch movement at 08:08:42 UTC. Hypothetically, pilots deliberately move switch to reset system after noticing thrust loss with switches in RUN. 01:06 Engine 2 fuel cutoff switch transitions from RUN to CUTOFF. AAIB-reported: Switch movement at 08:08:43 UTC. Hypothetically, pilots continue reset attempt. 01:07 Ram Air Turbine (RAT) deploys, indicating dual engine failure and loss of primary power. AAIB-reported: RAT deployment noted but no timestamp provided. Hypothetically placed after switch movement, as thrust loss persists. CCTV confirms deployment during climb. Few experts have said that RAT would require 6+ seconds to automatically deploy after a dual engine failure 01:08–01:14 Pilots notice persistent thrust loss despite switches in CUTOFF, prepare to return switches to RUN to attempt engine relight. Hypothetical: Assumes pilots assess situation and follow emergency procedures (e.g., engine restart checklist) within seconds, constrained by short timeline. 01:15 Engine 1 fuel switch transitions from CUTOFF to RUN, initiating relight attempt. AAIB-reported: Switch movement (transition) at 08:08:52 UTC. Hypothetically, pilots attempt to restore fuel flow after reset fails. 01:17 Engine 2 fuel switch transitions from CUTOFF to RUN, initiating relight attempt. AAIB-reported: Switch movement (transition) at 08:08:54 UTC. Hypothetically, pilots complete relight attempt for second engine. 01:18–01:27 Pilots observe one engine partially relighting but insufficient thrust to maintain flight. Aircraft begins descent. Hypothetical: AAIB notes one engine regained some thrust, but not enough to prevent crash. Descent aligns with 625-foot maximum altitude and crash 1.5 km from runway. 01:28 Pilots issue “MAYDAY MAYDAY MAYDAY” call. AAIB-reported: MAYDAY call at 08:09:05 UTC. Reflects pilots’ recognition of imminent crash. As seasoned pilots they follow the protocol in extreme emergencies - aviate, navigate & communicate (in that order) 01:34 Flight data recorder stops, aircraft crashes. AAIB-reported: Crash at 08:09:11 UTC, 32 seconds after liftoff, into B.J. Medical College hostel.
The 787-8’s fuel system is designed to respond to both manual pilot inputs and system-generated signals, reflecting its fly-by-wire architecture.
The Boeing 787-8’s fuel flow pipeline delivers fuel from tanks to engines via boost pumps, engine-driven pumps, and valves (spar, metering, cross-feed), controlled by a combination of manual fuel control switches and automated systems (FADEC - Full Authority Digital Engine Control, IFS - Integrated Fuel System). The switches manually actuate the spar valves, while the FADEC manages pumps and metering valves using sensor inputs and software logic. The NH985 incident confirms that software (TCMA - Thrust Control Malfunction Accommodation /FADEC) can reduce fuel flow without pilot intervention, but no evidence confirms it can close spar valves or mimic switch movement to CUTOFF, as seen in AI-171. The 787’s fly-by-wire design makes a software-induced cutoff theoretically possible, supporting my AI-171 scenario, but the AAIB’s focus on switch movement and lack of inquiry into software possibilities leaves this unresolved. Software malfunction could result from a bug or malware introduced by a saboteur. The fuel system’s electrical and electronic components enable both manual and system-driven control, with redundancy to prevent unintended cutoffs, but a rare glitch could disrupt this balance, as hypothesized for AI-171. The final AAIB report (due June 2026) should clarify whether such a malfunction occurred. In the near term, the Indian Pilots ought to haul AAIB to the court on charges of deliberate obfuscation, issuing a premature clean chit to Boeing and placing the integrity of Indian pilots under a cloud. AAIB should also be charged for leaking its draft report to Western media.
Reference: My Q&A with ChatGPT on premature clean chit AAIB gave to Boeing and what is Boeing design and training related to fuel flow cutoff and relighting engines. Link
This chat reveals a critical design flaw - in an emergency FADEC should NOT overrule manual FULL THRUST COMMAND; possibly (unless there were other factors at play) pilots could have pulled up their plane even at the last moment but for this flawed design - FADEC was the boss as the Fuel Control Switches were in the RUN state and it disregarded pilots by design and merrily regulated the fuel flow "efficiently", at its own pace!! Should the Pilots not be given a button sequence or a pass code to tell the FADEC to yield?
| Time (MM:SS) | Event | Remarks |
|---|---|---|
| 00:00 | Aircraft starts takeoff roll. | AAIB-reported: Takeoff roll begins at 08:07:37 UTC. |
| 01:02 | Aircraft reaches 155 knots, air/ground sensors transition to air mode, consistent with liftoff. | AAIB-reported: Liftoff at 08:08:39 UTC. |
| 01:03 | System malfunction reduces or cuts off fuel flow to both engines, triggering EICAS warnings and/or audible alarms (e.g., “ENGINE FAIL”). Commanding pilot (First Officer) detects dual engine thrust loss. | Hypothetical: Assumes system (e.g., FADEC/TCMA) malfunction causes thrust loss one second after takeoff, as per my scenario. Alerts align with standard 787 cockpit warnings. |
| 01:04 | Commanding pilot asks, “Why did you cut off?” Other pilot responds, “I didn’t.” Pilots observe fuel control switches in RUN position despite thrust loss. | Hypothetical: Places CVR conversation one second after thrust loss detection, consistent with pilot confusion noted in AAIB report. AAIB confirms conversation but provides no timestamp. |
| 01:05 | Engine 1 fuel cutoff switch transitions from RUN to CUTOFF. | AAIB-reported: Switch movement at 08:08:42 UTC. Hypothetically, pilots deliberately move switch to reset system after noticing thrust loss with switches in RUN. |
| 01:06 | Engine 2 fuel cutoff switch transitions from RUN to CUTOFF. | AAIB-reported: Switch movement at 08:08:43 UTC. Hypothetically, pilots continue reset attempt. |
| 01:07 | Ram Air Turbine (RAT) deploys, indicating dual engine failure and loss of primary power. | AAIB-reported: RAT deployment noted but no timestamp provided. Hypothetically placed after switch movement, as thrust loss persists. CCTV confirms deployment during climb. Few experts have said that RAT would require 6+ seconds to automatically deploy after a dual engine failure |
| 01:08–01:14 | Pilots notice persistent thrust loss despite switches in CUTOFF, prepare to return switches to RUN to attempt engine relight. | Hypothetical: Assumes pilots assess situation and follow emergency procedures (e.g., engine restart checklist) within seconds, constrained by short timeline. |
| 01:15 | Engine 1 fuel switch transitions from CUTOFF to RUN, initiating relight attempt. | AAIB-reported: Switch movement (transition) at 08:08:52 UTC. Hypothetically, pilots attempt to restore fuel flow after reset fails. |
| 01:17 | Engine 2 fuel switch transitions from CUTOFF to RUN, initiating relight attempt. | AAIB-reported: Switch movement (transition) at 08:08:54 UTC. Hypothetically, pilots complete relight attempt for second engine. |
| 01:18–01:27 | Pilots observe one engine partially relighting but insufficient thrust to maintain flight. Aircraft begins descent. | Hypothetical: AAIB notes one engine regained some thrust, but not enough to prevent crash. Descent aligns with 625-foot maximum altitude and crash 1.5 km from runway. |
| 01:28 | Pilots issue “MAYDAY MAYDAY MAYDAY” call. | AAIB-reported: MAYDAY call at 08:09:05 UTC. Reflects pilots’ recognition of imminent crash. As seasoned pilots they follow the protocol in extreme emergencies - aviate, navigate & communicate (in that order) |
| 01:34 | Flight data recorder stops, aircraft crashes. | AAIB-reported: Crash at 08:09:11 UTC, 32 seconds after liftoff, into B.J. Medical College hostel. |
The 787-8’s fuel system is designed to respond to both manual pilot inputs and system-generated signals, reflecting its fly-by-wire architecture.
The Boeing 787-8’s fuel flow pipeline delivers fuel from tanks to engines via boost pumps, engine-driven pumps, and valves (spar, metering, cross-feed), controlled by a combination of manual fuel control switches and automated systems (FADEC - Full Authority Digital Engine Control, IFS - Integrated Fuel System). The switches manually actuate the spar valves, while the FADEC manages pumps and metering valves using sensor inputs and software logic. The NH985 incident confirms that software (TCMA - Thrust Control Malfunction Accommodation /FADEC) can reduce fuel flow without pilot intervention, but no evidence confirms it can close spar valves or mimic switch movement to CUTOFF, as seen in AI-171. The 787’s fly-by-wire design makes a software-induced cutoff theoretically possible, supporting my AI-171 scenario, but the AAIB’s focus on switch movement and lack of inquiry into software possibilities leaves this unresolved. Software malfunction could result from a bug or malware introduced by a saboteur. The fuel system’s electrical and electronic components enable both manual and system-driven control, with redundancy to prevent unintended cutoffs, but a rare glitch could disrupt this balance, as hypothesized for AI-171. The final AAIB report (due June 2026) should clarify whether such a malfunction occurred. In the near term, the Indian Pilots ought to haul AAIB to the court on charges of deliberate obfuscation, issuing a premature clean chit to Boeing and placing the integrity of Indian pilots under a cloud. AAIB should also be charged for leaking its draft report to Western media.
Reference: My Q&A with ChatGPT on premature clean chit AAIB gave to Boeing and what is Boeing design and training related to fuel flow cutoff and relighting engines. Link
This chat reveals a critical design flaw - in an emergency FADEC should NOT overrule manual FULL THRUST COMMAND; possibly (unless there were other factors at play) pilots could have pulled up their plane even at the last moment but for this flawed design - FADEC was the boss as the Fuel Control Switches were in the RUN state and it disregarded pilots by design and merrily regulated the fuel flow "efficiently", at its own pace!! Should the Pilots not be given a button sequence or a pass code to tell the FADEC to yield?
No comments:
Post a Comment