Towards the end he mentions that the Fuel Cutoff switches were returned to the RUN position and that Engine one had arrested the deacceleration of its core and started to build thrust again but that engine two had not. Speculates that the pilot 'guarding' the thrust levers may have inadvertently dropped their hand and hit the switches. Apparently there is a 'check for correct function' notice out on the switches but it's optional rather than mandatory.
Towards the end he mentions that the Fuel Cutoff switches were returned to the RUN position and that Engine one had arrested the deacceleration of its core and started to build thrust again but that engine two had not. Speculates that the pilot 'guarding' the thrust levers may have inadvertently dropped their hand and hit the switches.
That's why the switches are lift-to-move types, with a mechanical lock preventing hand pressure from moving them. Pictures of that type of switch are in this thread already, I'm not going to post another one here.
I'd expect doing the check would have waited for that airframe's next heavy check. D phase, IIRC. Which I believe happen every couple of years and feature the whole interior getting stripped out and refurbished.
And it's unlikely that people would have recorded checking this unless the parts failed.
Flaps add drag. If your aircraft is Uber-engined like a 787 does (think that it is tailored to fly out on a single engine), it wouldn't be surprising that only minimum flaps are required when you have enough runway for your takeoff run.
You can see that most 787 have only minimal flaps at takeoff.
A quick online search would confirm you that normal settings are 5 to 15 only.
What's surprising is that they did not extend more of them post cutoff selection.
That's why the switches are lift-to-move types, with a mechanical lock preventing hand pressure from moving them. Pictures of that type of switch are in this thread already, I'm not going to post another one here.
I'd expect doing the check would have waited for that airframe's next heavy check. D phase, IIRC. Which I believe happen every couple of years and feature the whole interior getting stripped out and refurbished.
India's civil aviation regulator has released a preliminary report indicating that both of the jet's fuel cutoff switches flipped to the "cutoff" position shortly after take-off - but neither pilot believed they had moved the switches manually.
www.flightglobal.com
So it's entirely possible the switches were not lift to operate, even if the pilots expected them to be. They've recovered the panel, so that should be checkable.
While the Air India Boeing 787-8 crash inquiry has found that fuel control cut-off switches were activated almost as soon as the aircraft lifted off, the circumstances of the switches' movement remain unexplained. Preliminary findings from India's Aircraft Accident Investigation Bureau simply...
www.flightglobal.com
Flight notes that the aircraft had a Stabiliser Trim transducer error recorded on arrival, and that the Stabiliser Trim Cut-off switches are immediately to the left of the Fuel Cut-off switches. So there's a whole bunch of things to consider.
Plus, plane was in a total electrical/hydraulic failure so moving flaps etc would have been BAD. There's only so much fluid stored in the accumulators to power things while the pumps aren't working fast enough.
India's civil aviation regulator has released a preliminary report indicating that both of the jet's fuel cutoff switches flipped to the "cutoff" position shortly after take-off - but neither pilot believed they had moved the switches manually.
www.flightglobal.com
So it's entirely possible the switches were not lift to operate, even if the pilots expected them to be. They've recovered the panel, so that should be checkable.
Yes, I suspect that one of the first things to happen is checking the switches now.
But my point was that you're checking those switches at a D Check anyways. It's a sub-item on a list.
If the airframe in question hasn't hit Phase D yet, you're not going to have checked those switches.
If the airframe has hit Phase D, I'm not sure that there's a separate line item for those switches specifically to be checked.
It's a general "check all switches for proper operation" line item.
So I wouldn't necessarily expect someone to write that they checked the FCO switches IAW SAIB NM-18-33, when the SAIB itself only asks for reporting if bad switches are found.
So if someone did a records search for "SAIB NM-18-33," they wouldn't find anything because they needed to search for the general cockpit switch line item.
While the Air India Boeing 787-8 crash inquiry has found that fuel control cut-off switches were activated almost as soon as the aircraft lifted off, the circumstances of the switches' movement remain unexplained. Preliminary findings from India's Aircraft Accident Investigation Bureau simply...
www.flightglobal.com
Flight notes that the aircraft had a Stabiliser Trim transducer error recorded on arrival, and that the Stabiliser Trim Cut-off switches are immediately to the left of the Fuel Cut-off switches. So there's a whole bunch of things to consider.
I would not expect the pilots to fly the plane with Stabilizer Trim ON if there was an error reported at arrival. However, if they did, there'd be a Stab Trim error in the logs.
A leading aviation safety expert has suggested that the fatal crash of Air India Flight 171 may have been the result of deliberate human action, raising, for the first time, the possibility of a pilot-induced crash.
www.ndtv.com
This piece of information seems pertinent:
"Captain Ranganathan claimed that several serving Air India pilots had informed him that one of the flight crew members had a known medical history and had been on extended medical leave prior to the crash."
Is it possible that one of the pilots was not fully fit to fly and that could explain committing such a shocking mistake ?
That's why the switches are lift-to-move types, with a mechanical lock preventing hand pressure from moving them. Pictures of that type of switch are in this thread already, I'm not going to post another one here.
Yah. I think he was leaning away pretty hard from the idea that a professional pilot would either a) deliberately move them, or b) have enough brain fade to accidentally move them. The cockpit recorder has one pilot (they don't say which) asking the other why he shut off the fuel and the other replies that he didn't. We may never know.
Unfortunately I suspect we'll never truly know why. I feel fairly confident that if it was suicide there'd be indication in the CVR conversation; e.g. not participating in recovery, resign response to the 'wtf did you do that for question", voice stress indications, etc. I would expect if this was the case there'd be rumor by now.
> Entire nation of India & UK waiting for report in working day hours, but Report released in after-work hours.
> Data from forward EAFR downloaded on 24th June 2025.
49 hours of flight data spanning 6 flights including crash flight.
> Rear EAFR significantly damaged. Data couldn't be downloaded by conventional means. >>>>> No info if unconventional means tried or not.
> Earlier an error message 'STAB POS XDCR' or "Stabilizer position transducer" was about the sensor sending data about stabilizer to FMC, which was troubleshooted.
> T/o weight was 213,401 Kgs loaded Vs 218,183 Kgs allowed. >>>>> More weight adds to more loss in altitude. But i guess this is done till allowed limit by all airlines.
> No pilot names or captain/FO mentioned for conversation from CVR. >>>>> WHY????
Only 1 line mentioned about one asking other why he cutoff fuel & other saying he did not. >>>>> Why not full conversation from T/o roll till crash????
> A/c departed from bay-34 at 7:48:38 UTC/GMT, started rolling for t/o at 8:07:37 UTC/GMT, so 19 mins from bay to t/o roll.
> MLG was seen tipped forward (happens when gear lever put up) but gear lever found in down position!!!! >>>>> Perhaps it moved down due to crash impact.
> Thrust levers found at idle but EAFR data says they remained forward till impact. >>>>> Again, perhaps they moved back due to crash impact.
> Fuel switches were found in RUN position (as expected for relight).
> The SAIB in 2018 to inspect the fuel switches & take suitable action. >>>>> Was this done for AI-171??
> N2 spool RPM passed below idle before restart attempt. >>>>> here an engineer or 787 pilot needs to comment if the fuel switches can be switched back on immediately within say 5 seconds after checking fire.
> RAT deployed as expected, captured by another CCTV from left side, >>>>> WHY not shared to media earlier????????
> Fuel samples testing from fuelling bowsers & tanks showed no contamination.
> Fuel samples from APU filter, refuel/jettison valve ofleft wing yet to be tested.
> Timeline -
8:8:39 UTC/GMT / 1:38:39 pm IST - take-off, left runway.
8:8:42 UTC/GMT / 1:38:42 pm IST - speed 333 Kph, fuel cut off to both engines in 1 second interval.
8:8:47 UTC/GMT / 1:38:47 pm IST - Both N2 spool RPM went below Idle; RAT hydraulic pump started supporting flight controls.
8:8:52 UTC/GMT / 1:38:52 pm IST - engine 1 switched back on, worked.
8:8:54 UTC/GMT / 1:38:54 pm IST - APU auto start began, inlet door opened.
8:8:56 UTC/GMT / 1:38:56 pm IST - engine 2 switched back on, but didn't work.
8:9:05 UTC/GMT / 1:39:05 pm IST - Mayday call.
8:9:11 UTC/GMT / 1:39:11 pm IST - flight recorder stopped (crash).
8:14:44 UTC/GMT / 1:44:44 pm IST - Airport Fire trucks left airport for crash site.
Time T = take-off
+3 seconds
T+3 sec = fuel cutoff to both engines.
+5 seconds
T+8 sec = N2 spools RPMs below idle; RAT hydraulic pumps on.
+5 seconds
T+13 sec = engine 1 switched on, worked.
+2 seconds
T+15 sec = auto APU start, inlet door opened.
+2 seconds
T+17 = engine 2 switched on, didn't work.
+9 seconds
T+26 sec = Mayday call
+6 seconds
T+32 sec = crash, recorder stopped.
After fuel cutoff -
> RAT deployed immediately & took 5 seconds to start its hydraulic pump (& electricity too). > APU autostart took 12 seconds to initiate. > Engine 1 was switched on after 10 seconds.
> Engine 2 was switched on after 14 seconds (4 seconds after engine 1).
> These modern jets are said to survive 1x engine failure continuing +ve flight climb, go around & land.
But, Heavy A/c contributing to downward inertia post Apogee + RPMs going below idle + only 1 engine relighted giving inadequate thrust for immediate climb, made the plane crash.
So "thrust not achieved" means not enough to go back up immediately.
A preliminary investigation found the switches had been turned off in June's fatal Air India crash.
www.bbc.co.uk
"Although the fuel control switch design, including the locking feature, is similar on various Boeing airplane models, the FAA does not consider this issue to be an unsafe condition that would warrant an Airworthiness Directive on any Boeing airplane models, including the Model 787," said the [FAA], in an internal note shared with the BBC.
> Technically can both switches be manually shut off in 1 second? YES.
> But suicide-mass-murder that too of most people of same community &/or nationality, is a way too heavy accusation & needs carefull backing with medical records, exceptional public behavior symptoms of pilot, etc.
> Prelim report is incomplete w/o full exact CVR transcript & time stamp, hence is heavily criticized not only by Indian ALPA, etc but globally, suspected to be manipulated.
> Having foreign CEO is normal but still I wonder if Air India could have CEO from IIT+IIM.
> Audio can reflect emotions like screaming, exclaiming, yelling, scolding, frustration, surprise, etc, not a short, blunt, incomplete, suspected writing.
> Otherwise, many people are suspecting FO also that he did some mistake & tried to mislead CVR recording. What if the captain said "I didn't..... You did that!!!"???
> Tech glitch can show on MFD like wrong operation leading to wrong reaction, misunderstanding, accusation, etc especially if pilots don't get along well.
> Boeing has been caught lying in other cases.
> Boeing employees have been whistle blowers.
> Boeing, GE CEOs, managers, employees post crash are not coming forward to educate public on 787 systems.
> Pilots who have flown with deceased captain Sumeet Sabharwal have said in interviews to news channels that he was good, stable person & training other pilots.
> Nobody is talking straight IF at all captain Sumeet had any medical condition & what exactly.
> If pilot wants to commit suicide, they can do it with kitchen knife, drink poison, jump from buildings, ram their cars to walls or off bridge, flyover, etc, etc, etc. Killing people mostly from their own community is an act of huge mental retardation or if with some grievance then would be visible prior via some public interactions.
> CAUTION - As suicide-mass-murder is a big heavy crime, so all demographic caharacteristics will have to be factored in which can make public very uncomfortable, especially when India is very heterogenous nation.
> There are HR rules of behavioral conduct everywhere. So IF at all they disliked eachother then they would stick strictly to their job only, not exchange personal talks & could misunderstand/suspect eachother in case of any work anomalies. This happens in every office daily what we call 'office politics'.
> If switch is mechanically faulty & suspected to move down in normal/operational condition then by crash impact it cannot stay in up/on position like in this case.
>The SAIB for fuel switch was released in 2018 but not followed by Air India as it was advisory, not mandatory. This can be negligence, over-confidence over component performance.
Now this new video by a pilot on the SAIB says that fuel switch in various Boeing models are identical & can have mechanical problems if installed with "locking feature" disengaged.
> A comment on his video reveals that in Embraer jets the fuel cutoff won't be done unless the throttle is pulled back to idle. "Embraer will not let you shut the fuel off or close the fuel valves unless the throttle aren't at idle. To just kill the fuel with both engines at full TOGO is unbelievable."
This is perhaps a safety feature & in Boeing too, as per 1x engine failure/relight procedure during take-off in B-787 (YT videos) -
- the fuel switch red light turns on.
- Surviving engine is enough for +ve flight.
NOTE - This doesn't auto-start RAT or APU unless additional conditions ar met.
- Both pilots coordinate to follow checklist & acknowledge each other t every step.
- The MFD displays probable reason like fire, etc. - Auto-throttle switch for affected engine is switched off in UFC panel. - Affected side throttle is put to idle.
- THEN AFFECTED SIDE FUEL SWITCH IS CUTOFF.
- Fire handle of affected side is pulled up & turned to discharge fire bottle.
This procedure takes time. But in dual failure it is instant emergency. based on this procedure, the pilots should immediately check for fire & if no fire then -
- switch off both auto-throttle switches in UFC panel.
- pull back both throttles to idle.
- switch off both fuel switches then on.
- Either EEC should auto-arm & light the ignitors or engine knobs in overhead panel need to be rotated from NORM to START.
So it is basically a 3-point operation -
- Auto-throttle switch off in front.
- Pull throttles back.
- Switch off fuel switch.
THIS MEANS AS PER S/W CONTROLLED PROTECTION THE FUEL HARD SWITCH CUTOFF OPERATION WILL NOT BE RELAYED FROM FMC TO EEC UNLESS THE THROTTLE IS PULLED BACK TO IDLE.
SO THIS WHOLE ACCUSATION OF CAPTAIN (FAR MORE EXPERIENCED THAN FO) SWITCHING OFF FUEL SWITCHES IN 1 SECOND WHEN THROTTLE IN FORWARD POSITION, IS TECHNICALLY IMPOSSIBLE.
As i said, some people are also suspecting the less experienced FO who might have made some mistake & tried to mislead the CVR.
> In India the IPC (Indian Penal Code) 499, 500 deals with defamation & propaganda issues in any form.
> Revenge sabotage by Pakistan, Turkey, etc post Pahalgam terror attack & retaliation on terror camps, is also being considered like announced by miniter of Civil Aviation Mr. Murlidhar Mohol.
> Political sabotage to defame rulling party is also considered, although will never be proven publicly even if true bcoz it'll lead to political violence & perhaps a civil war too.
> Bcoz of all these points, most people who earlier confidently suspected pilot error or suicide, etc are currently either distancing off or at least pausing until full exact CVR with time stamp is publicized.
5.12.3 The names of the persons involved in the accident or incident shall not be disclosed to the public by the accident investigation authority.
Captain/First Officer determination will need identification by people familiar with them, for every comment from power-up on, which they may not have done yet. Or they may not wish to commit themselves pending further analysis.
Only 1 line mentioned about one asking other why he cutoff fuel & other saying he did not. >>>>> Why not full conversation from T/o roll till crash????
> These modern jets are said to survive 1x engine failure continuing +ve flight climb, go around & land.
But, Heavy A/c contributing to downward inertia post Apogee + RPMs going below idle + only 1 engine relighted giving inadequate thrust for immediate climb, made the plane crash.
So "thrust not achieved" means not enough to go back up immediately.
Being able to maintain controlled flight on one engine depends on that engine being able to deliver at least cruise power and the aircraft not being in a vulnerable low-speed condition. If it's spooling up from under ground idle speed, then it's not surprising it never got beyond "started to progress to recovery" in the 19 seconds between the fuel cutoff being reversed and the loss of EADR data. It's noticeable the precise time of (inferred?) relight is not given in the timeline, but we can safely presume it's several seconds after the fuel valves are reopened.
No, it was funny to read you depicting an entire nation just waiting for a report during their working hours... While India hasn't really already an image of worker efficiency in the popular say.
That's it.
> Prelim report is incomplete w/o full exact CVR transcript & time stamp, hence is heavily criticized not only by Indian ALPA, etc but globally, suspected to be manipulated.
It's only criticised by people who don't understand what's in the typical preliminary report. For instance here's the NTSB preliminary report on the DC mid-air, which has to cover two separate aircraft and crews, plus ATC, and still only runs to 20 pages:
That line is highly generic.
No photos available. So what exactly damaged? How much damaged? Can parts be recovered?
There is an entire industry dedicated to recovering digital data.
You must be knowing about RAID, etc.
5.12.3 The names of the persons involved in the accident or incident shall not be disclosed to the public by the accident investigation authority.
Captain/First Officer determination will need identification by people familiar with them, for every comment from power-up on, which they may not have done yet. Or they may not wish to commit themselves pending further analysis.
> It is already known that FO was in operating pilot role & captain was observing co-pilot role. So people have come to know further that who asked "why did you cutoff?" & who replied "I didn't".
So now there is nothing to hide further in the name of security, protocols, rules, etc. from the transcript it can be easily known who says what.
> The ICAO document title is "International standards & RECOMMENDED practices". Recommendation is not Enforced rule.
> It does need consent from states involved & ICAO if ICAO documents involved.
> 5.12.3 looks very generic. It doesn't seem to state alive/dead. May be it is concerned with security of people who are alive & part of doing active investigation (that's obvious), rather than dead.
> A recorded conversation is a fact & proof, here it is ultimate truth, key to unlocking mystery of disaster. So hiding the proof is a crime.
> Inside the airline office there are numerous people who know the pilots, who can identify the voices of recording.
> Differentiating b/w a 30s guy & a 50s guy is not tough.
> This report only added anger, dissatisfaction, confusion, more speculations, good for news channels & people who wanna come before camera.
> But there are many crash time audio released to public. Many have been uploaded on YouTube, etc.
So there are 2 ways now -
- Maintain anonimity of which pilot said what resulting in all kinds of unrest - legal, social, political, industrial.
- Release full CVR.
Personally i don't think truth will come out & justice will be served. India wil give up to Western pressure & domestic corruption.
Ok, attention concentrated, primary safety issue identified, now more data is demanded by citizens.
The organisations/officials can deny but the matter could be taken legally to incident nation's Supreme court too.
The news channels are reporting that victims' families are preparing for court fight in India as well as in UK.
"Engine 2 was able to relight"
It worked. "but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. "
Ultimately, compared to engine 1 relight & spin-up, engine 2 could not arrest core deceleration & didn't spin up to 100% RPM in time, right? That's what people wan't to understand.
"As per the EAFR data both engines N2 values passed below minimum idle speed"
The engine wasn't even at ground idle (aka 'minimum idle'), never mind flight idle, it takes time to spin-up an engine that's all but stopped.
Like i said earlier, we can notice on ground that -
- when N2 reaches 15-20% RPM then fuel is provided.
- 0% to idle can take 45-60 sec &,
- during T/o when pilot pushed throttle to full, then idle to 100% takes 2-4 sec.
So during engine loss of power -
> How many seconds for 100% down to flight idle?
> Is there any spool rotation braking effort?
> How many seconds from flight-idle to 100%?
Decade after decade, in every country, today there are 100s of 1000s of various types of techies in society.
So the notch of expectations of citizens has gone up.
Things change with time.
No, it was funny to read you depicting an entire nation just waiting for a report during their working hours... While India hasn't really already an image of worker efficiency in the popular say.
That's it.
India is developing nation, so it'll lag behind the developed ones.
There is domestic corruption but certain organisations in public & private sector have done well like ISRO, the S/w MNCs, new startups, etc. It has given global CEOs, scientists, astronauts & other successful professionals in all domains. The politicians of all parties need to be qualified.
Rest is upto people what they wanna focus on.
World is in grey shades everywhere.
In past few decades India was in import-culture.
Let's see how it does in next few decades in its self-reliance push.
Stop.
Just STOP!
By your own admission you are NOT an aerospace expert, so STOP trying to second guess the investigators.
This is a PRELIMINARY report, required by law to be released within 30 days of the accident occuring. It is just a rough snapshot of the evidence found to date. Now that this report has been released, the investigation can start in earnest.
It may take years . . .
@Low IQ Techie : it was just a cheap joke, just like saying English food is horrible (it is not) or French are always on strike... It obviously does not embrace the whole of a nation. Let´s move on (as the joke failed even pitifully).
Stop.
Just STOP!
By your own admission you are NOT an aerospace expert, so STOP trying to second guess the investigators.
This is a PRELIMINARY report, required by law to be released within 30 days of the accident occuring. It is just a rough snapshot of the evidence found to date. Now that this report has been released, the investigation can start in earnest.
It may take years . . .
OOOHH!!!! I'm so sorry buddy, I didn't know that Computer Engineers reading, watching about Aeronautics since 30 years can't talk about it. Perhaps we should register here by Aero-engineering degree only.
Perhaps as per your logic, for example, 3D artists should not make CAD for guessing F-47, GCAP, FCAS, etc. They have already made numerous small mistakes in their design. Buti still I deeply appreciated them all. Should i tag all those artists here to convey your message?
I am not sure both switches could be shutoff in a second if the guard was working, if the guard wasn't working then yes it would be possible but if the guard was working then that requires four individual hand movements in a second and the data recorder shows they weren't flipped simultaneously.
Decade after decade, in every country, today there are 100s of 1000s of various types of techies in society.
So the notch of expectations of citizens has gone up.
Things change with time.
> T/o weight was 213,401 Kgs loaded Vs 218,183 Kgs allowed. >>>>> More weight adds to more loss in altitude. But i guess this is done till allowed limit by all airlines.
> No pilot names or captain/FO mentioned for conversation from CVR. >>>>> WHY????
Only 1 line mentioned about one asking other why he cutoff fuel & other saying he did not. >>>>> Why not full conversation from T/o roll till crash????
> This is not some private property accident. We should keep ourselves in place of people who lost their loved ones.
> Global human society has changed rapidly in every aspect in last 100-150 years.
> Globalization, International education & jobs, trade & commerce, colaborations, Internet & social media, Information proliferation, have allowed citizens to expand their knowledge, comprehension.
> So primitive exclusive systems have become more opportunistic.
> Private think tanks & consultants have come up, who also don't participate in national level investigation.
> In every industrial domain, there are levels of jobs corresponding to expertise levels. So minimum skilled to highly specific skilled people work in there.
> Many CEOs & managers are not qualified &/or experienced in the domian of the company they are heading/managing but they're MBA.
> When people loose their friends/family, in democracy, the qualified citizens should have right to comprehend whatever they can.
> Info demanders Vs deniers, this tussle wil continue. That's why we've parliament, bills, court, voting, etc. At some places there is RTI (Right to Information) & other places we don't have.
> In this remaining century we'll see many types of changes & reforms, some subtle, some expected, some unexpected.
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