Air India B787 crash Ahmedabad

[oz_mark]

If India follows the norm and publishes an initial report after 14 days then I fear that at the moment we are unlikely to learn much from the initial report other than things that they have ruled out.

I think 30 days is more normal.

 

[OATEK]

It's interesting, though his presentation has reached the breathless level.

My fear would actually be that they don't. Basically a tree of possibilities with a branch missing.


I'm finding it odd that they're going to the conclusion stage, though I have no objection to being given possible paths. Cap'n Steve has given us pilot error, then changed his mind, and is now in the fuel issue camp. Hoover is blaming the pilots, apparently going with the theory of an engine failure, followed by shutting the wrong one down - which doesn't explain the gear, and which they simply never would have gotten to, given that Boeing don't start cleaning up issues until you reach 1,000'. And now Gary seems to be in the electrical camp. It doesn't really matter if it's a million, or billion, to one chance. Remember that this is also an older aircraft in this fleet, which may throw up other issues.

Personally I've always wondered about the software, so I think we're wondering about the same thing.

GaryBpilot seems very interested in this line of enquiry about when/how engine fuel lines can be shut automatically:

 

[jb747]

This is a totally ignorant comment by me but I would have thought issuing a mayday was the furthest thing from the flight deck’s mind in a situation like that.

Possibly sounds strange, but the non flying pilot might have had a few seconds when he wasn’t doing anything…in large part because there’s nothing you can really do in this sort of situation. Again, the timing of the call, relative to the aircraft’s position will be relevant. And pilots, can multi task (my wife says I can’t, but ). You could be trying to pull the gear up, whilst you simultaneously make a call.

 

[jb747]

GaryBpilot seems very interested in this line of enquiry about when/how engine fuel lines can be shut automatically:

It’s interesting if true, but I’m not convinced that looking for the smoking gun is a great idea, with such limited information. Nevertheless, a default position of ”shut down” seems inappropriate for anything that flies. Whether that’s really correct, I don’t know.

 

[Rabs97]

Cap'n Steve has given us pilot error, then changed his mind, and is now in the fuel issue camp. Hoover is blaming the pilots, apparently going with the theory of an engine failure, followed by shutting the wrong one down - which doesn't explain the gear, and which they simply never would have gotten to, given that Boeing don't start cleaning up issues until you reach 1,000'. And now Gary seems to be in the electrical camp.

Do they get a trophy if their random guess turns out to be correct?

 

[RSD]

It’s interesting if true, but I’m not convinced that looking for the smoking gun is a great idea, with such limited information. Nevertheless, a default position of ”shut down” seems inappropriate for anything that flies. Whether that’s really correct, I don’t know.

Someone at Boeing might have needed to put some additional risk mitigation in for post accident fire so decided that if the valves have lost all electrical power then they should fail closed...

Sometimes logical thinking gets overridden by the desire (or pressure) to make a risk assessment pass...

 

[Peregrine]

It’s interesting if true, but I’m not convinced that looking for the smoking gun is a great idea, with such limited information. Nevertheless, a default position of ”shut down” seems inappropriate for anything that flies. Whether that’s really correct, I don’t know.

I'm no aviator or engineer, and while there ars different systems involved, my reading of commentary elsewhere eg PPRuNe forums (Search HPSOV High pressure shut off valve) is that the "Loss of power, engine shut-down scenario" has been debunked - it appears that EVERY VALVE IN THE FUEL SYSTEM MUST BE POWERED TO CHANGE STATE ie if power is lost the valve stays where it was.

 

[jb747]

...... EVERY VALVE IN THE FUEL SYSTEM MUST BE POWERED TO CHANGE STATE ie if power is lost the valve stays where it was.

Which is what you'd actually expect. Those looking for the smoking gun are struggling though, because it looks like a dual engine failure, but it's almost impossible to explain how that could happen.

I have a theory about aircraft accidents, to the effect that they seem to become stranger, and less likely. The reason is that training, CRM, and engineering, have taken away many of the historic causes, so now everything seems to be an outlier. Of course, all three of those 'cures' are less than 100% effective.

 

[markis10]

Spoiler: Unfactual Information

[Moderator Edit]

*** Note; This content has been shown to be unsubstantiated speculation originally published by an unreliable source - see following posts regarding the non-validity of this content ***

Air India 171 Crash
AAIB Preliminary Report Highlights
1.⁠ ⁠Primary Cause – Electrical Power Transfer Interruption (PTI) During Rotation
• During transition from ground to airborne electrical configuration, the aircraft experienced a cascading dual-engine FADEC (Full Authority Digital Engine Control) failure.
• Root cause: Uncommanded bus transfer failure due to arcing in the main power relay box (PRB-A), traced to water ingress during pre-flight GPU disconnection in heavy rain.
• This led to loss of electronic engine control at rotation, resulting in both GEnx engines rolling back to ground idle within 4–5 seconds.
2.⁠ ⁠Flight Data Record Timeline
• +0:11 sec: Nose gear lifts off.
• +0:13 sec: Sudden engine rollback begins. Thrust reduces from 92% N1 to <27% within 3 seconds.
• +0:16 sec: Master caution + ENG FAIL L/R warnings. FO calls, “Both engines dropping!”
• +0:20 sec: Autopilot and flight control reverts to Direct Mode. Pitch up attitude peaks at 18°.
• +0:25 sec: Aircraft stalls at 186 ft AGL.
• +0:30 sec: Full aerodynamic stall; nose drops rapidly.
• +0:38 sec: Ground impact at 54° nose-down attitude, 174 knots.
⸻
Contributing Factors
• Environmental Conditions:
• Torrential rain during pushback.
• Moisture intrusion into PRB-A connector (P/N: HLN8471) — a known corrosion-risk component.
• Latent Maintenance Issue:
• Power transfer relay unit showed signs of thermal damage in a previous MEL deferral 2 weeks prior.
• No replacement had been conducted; aircraft was cleared under repetitive deferral.
• Design Oversight:
• Boeing 787 has no physical engine control backup (i.e., no direct mechanical linkage in FADEC loss scenario).
• Loss of power supply to both EEC channels resulted in engine “freeze” at ground idle instead of flameout.
• Flight Crew Response:
• Attempted engine relight sequence not completed before stall onset.
• Emergency power selector not activated — possibly due to confusion from multiple ECAM warnings.
⸻
Immediate Safety Actions
• DGCA + EASA + FAA Emergency AD issued within 24 hours:
• Mandatory PRB-A moisture integrity inspection on all Boeing 787 aircraft.
• Temporary restriction on dispatch with MEL items related to power transfer systems.
• Boeing:
• Issued Service Bulletin SB-787-24-212 requiring replacement of PRB-A connectors with sealed versions.
• Exploring addition of dual-path power redundancy for FADEC systems.
⸻
Lessons Learned
• Over-reliance on electrical power distribution architecture without layered redundancy.
• Lack of crew procedural training for full engine rollback during takeoff in EEC dual failure scenarios.
• Need for improved environmental sealing in GPU/electrical handover units in monsoon zones.
⸻
Timeline – What’s Next?
• Aug 15, 2025: Release of FAA/Boeing electrical design audit report
• Sept 5, 2025: ICAO session on electrical-critical phase-of-flight risk mitigation
• Oct 2025: Mandated design retrofit across 787 fleet (rev. SB-787-24-219)


Source Aviation-knowledge

Official report if the above is real is yet to appear on the AAIB website, if it’s real the detail is quite comprehensive.

 

[MEL_Traveller]

The above was ‘reported’ 6 days ago in a linked in post by an a320 pilot. The origins go back even further according to comments… this alleged claim has been around since as early as 15 June.

Linked in post: Flight AI171: | Matej Pušlar

 

[Saab34]

Even if the above was true, would an engine relight change the outcome here?

The only saving grace it seems would have been green fields ahead of them not buildings.

 

[oz_mark]

• Environmental Conditions:
• Torrential rain during pushback.

Really?

 

[markis10]

People do have a lot of time on their hands it seems

 

[DejaBrew]

People do have a lot of time on their hands it seems

Not having a dig at you here @markis10, but I find it quite disturbing that there are people out there manufacturing this sort of garbage and the motivations that compel them to do so are truly beyond me. It's one thing to speculate about what happened based on photos, videos, audio, general curiosity/interest, professional knowledge and experience et. al., but fabricating this nonsense and trying to pass it off as a a "scoop" of the legitimate report is truly over the top and thoroughly disrespectful to everyone involved including - not least of all - the flight crew, passengers and their respective families.

 

[markis10]

Not having a dig at you here @markis10, but I find it quite disturbing that there are people out there manufacturing this sort of garbage and the motivations that compel them to do so are truly beyond me

I would agree very strongly, I suppose it’s a product of the click bait media world we live in these days

 

[Saab34]

Seems like Airbus pilots online are loving this one with Boeing giving out ECAMs.

Just another reminder of the fake news and AI world we live in now.

The thing is, a whole bunch of media would run with it.

 

[MEL_Traveller]

Seems like Airbus pilots online are loving this one with Boeing giving out ECAMs.

Just another reminder of the fake news and AI world we live in now.

The thing is, a whole bunch of media would run with it.

That’s the thing… they didn’t run with it.

Because it couldn’t be verified.

 

[Saab34]

That’s the thing… they didn’t run with it.

Because it couldn’t be verified.

Sorry I should have rephrased, a whole bunch of blogs with hundreds of thousands of followers shared it.

 

[Rabs97]

Air India 171 Crash
AAIB Preliminary Report Highlights
1.⁠ ⁠Primary Cause – Electrical Power Transfer Interruption (PTI) During Rotation
• During transition from ground to airborne electrical configuration, the aircraft experienced a cascading dual-engine FADEC (Full Authority Digital Engine Control) failure.
• Root cause: Uncommanded bus transfer failure due to arcing in the main power relay box (PRB-A), traced to water ingress during pre-flight GPU disconnection in heavy rain.
• This led to loss of electronic engine control at rotation, resulting in both GEnx engines rolling back to ground idle within 4–5 seconds.
2.⁠ ⁠Flight Data Record Timeline
• +0:11 sec: Nose gear lifts off.
• +0:13 sec: Sudden engine rollback begins. Thrust reduces from 92% N1 to <27% within 3 seconds.
• +0:16 sec: Master caution + ENG FAIL L/R warnings. FO calls, “Both engines dropping!”
• +0:20 sec: Autopilot and flight control reverts to Direct Mode. Pitch up attitude peaks at 18°.
• +0:25 sec: Aircraft stalls at 186 ft AGL.
• +0:30 sec: Full aerodynamic stall; nose drops rapidly.
• +0:38 sec: Ground impact at 54° nose-down attitude, 174 knots.
⸻
Contributing Factors
• Environmental Conditions:
• Torrential rain during pushback.
• Moisture intrusion into PRB-A connector (P/N: HLN8471) — a known corrosion-risk component.
• Latent Maintenance Issue:
• Power transfer relay unit showed signs of thermal damage in a previous MEL deferral 2 weeks prior.
• No replacement had been conducted; aircraft was cleared under repetitive deferral.
• Design Oversight:
• Boeing 787 has no physical engine control backup (i.e., no direct mechanical linkage in FADEC loss scenario).
• Loss of power supply to both EEC channels resulted in engine “freeze” at ground idle instead of flameout.
• Flight Crew Response:
• Attempted engine relight sequence not completed before stall onset.
• Emergency power selector not activated — possibly due to confusion from multiple ECAM warnings.
⸻
Immediate Safety Actions
• DGCA + EASA + FAA Emergency AD issued within 24 hours:
• Mandatory PRB-A moisture integrity inspection on all Boeing 787 aircraft.
• Temporary restriction on dispatch with MEL items related to power transfer systems.
• Boeing:
• Issued Service Bulletin SB-787-24-212 requiring replacement of PRB-A connectors with sealed versions.
• Exploring addition of dual-path power redundancy for FADEC systems.
⸻
Lessons Learned
• Over-reliance on electrical power distribution architecture without layered redundancy.
• Lack of crew procedural training for full engine rollback during takeoff in EEC dual failure scenarios.
• Need for improved environmental sealing in GPU/electrical handover units in monsoon zones.
⸻
Timeline – What’s Next?
• Aug 15, 2025: Release of FAA/Boeing electrical design audit report
• Sept 5, 2025: ICAO session on electrical-critical phase-of-flight risk mitigation
• Oct 2025: Mandated design retrofit across 787 fleet (rev. SB-787-24-219)


Source Aviation-knowledge

Official report if the above is real is yet to appear on the AAIB website, if it’s real the detail is quite comprehensive.

It’s fake.

Mods or @markis10 - can you please delete that post? There’s enough nonsense floating around about this crash from YouTube “experts” we don’t need more of it.

 

[QF WP]

[MOD HAT ON]
I think it's best to wait until the official preliminary and final reports come out - both of which may take time. We don't have access to the black boxes data yet or the full ATC audio.

Everyone has their own opinion and some want to voice it. For those that rely on the speculation of others, there's a good lesson here. Fact checking happens after opinions are expressed.
[MOD HAT OFF]