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| PPRuNeUser548247
June 12, 2025, 12:16:00 GMT permalink Post: 11899151 |
Assuming we're not facing a repeat of the Boeing 737‑800 crash at Muan International Airport when loss of loss of both engines apparently also cut power to Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR)
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR FDR |
| PPRuNeUser548247
June 12, 2025, 12:44:00 GMT permalink Post: 11899172 |
The accident occurred in mid-afternoon, when bird activity around the Sabarmati river is known to peak, increasing strike risk to both engines.
SVPI ranks second in India for wildlife strikes | Ahmedabad News - Times of India Subjects: None |
| PPRuNeUser548247
June 12, 2025, 14:44:00 GMT permalink Post: 11899286 |
Possible timeline (all timing after brake-release)
Rotation +33s Mayday call +44s, circa 300 ft altitude (ADS-B) Peak altitude +49s, 625 ft (Flightradar24) Impact +58s, crash site 1.6 km from runway Subjects (links are to this post in the relevant subject page so that this post can be seen in context): ADSB FlightRadar24 MAYDAY |
| PPRuNeUser548247
June 13, 2025, 10:50:00 GMT permalink Post: 11900339 |
The Dreamliner as two identical “Enhanced Airborne Flight Recorders”, one in the tail section and one beneath the flight deck. Each one contains the CVR + FDR in one module, both have 10 minutes of battery power backup. I see reports that the one in the tail section has been recovered. All to easy to surmise the contents will be tampered with at the request of politicians/investors
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR FDR |
| PPRuNeUser548247
June 13, 2025, 11:00:00 GMT permalink Post: 11900350 |
Pax shared video of aircraft allegedly showing cabin lights, AC and entertainment system were already broken on flight into
Ahmedabad; electrical systems may already have been on the blink (see what I did there?)
Shocking video reportedly shows power failures inside Air India plane hours before it crashed
Subjects: None |
| PPRuNeUser548247
June 13, 2025, 15:03:00 GMT permalink Post: 11900610 |
Surely a Dreamliner pilot on Prune has a realistic Flight Sim where they can try taking off with each of the suggested faults/errors and see which one(s) result in the aircraft crashing in the way seen?
Subjects: None |
| PPRuNeUser548247
June 15, 2025, 09:48:00 GMT permalink Post: 11902302 |
I see Times of India is reporting the last call to ATC was
"Thrust not achieved… falling… Mayday! Mayday! Mayday!"
Ahmedabad Air India crash: Long runway roll hints at thrust failure, black box key to probe; officials reveal final moments in cockpit | Ahmedabad News - Times of India
Given the evidence now in the public domain of RAT auto-deployment and simultaneous roll back, with no bird strikes, the most plausible primary trigger is a simultaneous, fuel-related thrust failure on both GEnx-1B engines. Simultaneous FADEC failure seems less likely, at least without tampering. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FADEC MAYDAY RAT (All) RAT (Deployment) |
| PPRuNeUser548247
June 15, 2025, 12:18:00 GMT permalink Post: 11902422 |
There's some possible fuel contamination mechanisms which would only affect one aircraft
- The fuel truck’s water-absorbing “monitor” element breaks up, the first aircraft after the break gets the bead slug; later uplifts may be clear once the hose is flushed. The beads jam metering valves almost immediately. - After pipe maintenance, the first few hundred litres can carry residual cleaning surfactant that strips protective films and causes filter-monitor “soap lock”. - Biofilm growth happens inside one aircraft’s wing tanks when it sits in humid conditions or does short hops with warm fuel. On the next flight the biofilm shears off, blocks strainers, Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) |
| PPRuNeUser548247
June 17, 2025, 16:23:00 GMT permalink Post: 11904442 |
As more days pass without the FAA/EASA issuing an emergency Airworthiness Directive re. the 787 Dreamliner, it does appear more likely the cause of the crash was specific to the Air India aircraft (as per speculation on fuel contamination, bad maintenance, crew error etc. etc.)
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) |
| PPRuNeUser548247
June 17, 2025, 20:15:00 GMT permalink Post: 11904617 |
Without incurring the wrath of the moderators, can I add another improbable and maybe with current understanding impossible possibility.
Electro magnetic interference. Intended or accidential. I apologise that it might be another rabbit hole, but at present, and to quote the esteemed tdracer, 'never say never' and 'this is perplexing'. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Thread Moderation |
| PPRuNeUser548247
June 18, 2025, 12:18:00 GMT permalink Post: 11905193 |
I wonder if the delay in announcing any preliminary findings is because of the enormity of the consequences.
Let us say the investigation team have discovered a unique technical fault that caused the accident, but don’t yet know why it happened, how would the team proceed? On the one hand they’ve uncovered a fault which could reoccur and cause another accident (but a fault that has only happened once in 14 years). On the other hand a grounding would have enormous commercial consequences worldwide, with the possibility that an inspection and/or rectification are not yet available. What would they do? As I said in a previous post, every day that passes without a EAD suggest the cause was was specific to that aircraft (fuel contamination, maintenance failure, crew error - pick you own theory) Last edited by PPRuNeUser548247; 18th June 2025 at 12:43 . Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Air Worthiness Directives FAA Fuel (All) |
| PPRuNeUser548247
June 30, 2025, 08:28:00 GMT permalink Post: 11913431 |
We know that the right-hand GEnx-1B was removed for overhaul and re-installed in March 2025 so it was at \x93zero time\x94 and zero cycles, meaning a performance asymmetry that the FADEC would have to manage every time maximum thrust is selected. If the old engine was still on the pre-2021 EEC build while the fresh engine carried the post-Service Bulletin software/hardware, a dual \x93commanded rollback\x94 is plausible. A latent fault on one channel with the mid-life core can prompt the other engine to match thrust to maintain symmetry, leading to dual rollback.
Last edited by PPRuNeUser548247; 30th June 2025 at 11:43 . Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Dual Engine Failure Engine Failure (All) FADEC |
| PPRuNeUser548247
June 30, 2025, 13:59:00 GMT permalink Post: 11913645 |
That said, the continued absence of the FAA issuing an Emergency Airworthiness Directive for the Dreamliner suggests to me the fault was something like contaminated fuel which was specific to that flight. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FAA FADEC |
| PPRuNeUser548247
July 09, 2025, 12:59:00 GMT permalink Post: 11918376 |
Unfortunately, it's looking like poster's concerns about political interference, national pride in using a brand new lab in India to extract 'black box' content and the desire not to damage the reputation of a 'flag carrier' are well founded.
Subjects: None |
| PPRuNeUser548247
July 10, 2025, 16:08:00 GMT permalink Post: 11919112 |
With the recent (albeit unofficial) indications that both engine fuel control switches were found in the CUTOFF position, I wonder if it's time to reassess the tone and meaning of Captain Sabharwal's final transmission (perhaps translated from Hindi) “Thrust not achieved… falling… Mayday! Mayday! Mayday!”
Viewed in light of the reported switch positions, the phrasing feels increasingly ambiguous. As is often stated on PPRunE, communication comes after aviation so you wonder why in the crisis and at low altitude, this message was transmitted. Being so atypical, the message merits re-examination. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Switches MAYDAY RUN/CUTOFF |
| PPRuNeUser548247
July 10, 2025, 16:38:00 GMT permalink Post: 11919135 |
That said, switches found in the RUN position don\x92t generate investigative focus, they're assumed to be where they should be. The mere fact that the fuel switches are attracting attention implies there's something abnormal.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Switches RUN/CUTOFF |
| PPRuNeUser548247
July 11, 2025, 20:47:00 GMT permalink Post: 11919775 |
FAA issued an SAIB in 2018 about these fuel control switches being installed without the locking feature engaged\x97Air India didn\x92t act on it (not mandatory).
No evidence of birdstrike, fire, or mechanical failure. Both engines had good health data. The only obvious explanation at this stage is an inadvertent dual shutdown by crew, Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FAA Fuel (All) Fuel Cutoff Switches Special Airworthiness Information Bulletin |
| PPRuNeUser548247
July 11, 2025, 20:54:00 GMT permalink Post: 11919781 |
Subjects: None |
| PPRuNeUser548247
July 11, 2025, 20:57:00 GMT permalink Post: 11919789 |
That “I didn’t” on the CVR doesn’t sit right. If the cutoff switch movement was accidental, one would expect shock, confusion, or immediate troubleshooting, not a flat denial.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR Fuel (All) Fuel Cutoff Switches |
| PPRuNeUser548247
July 11, 2025, 21:35:00 GMT permalink Post: 11919842 |
It seems to me that there must have been further dialogue after the bland "I didn't". To have nothing reported after that two-line exchange, until the MAYDAY at 08:09:05, is a highly suspect omission from the interim report. In a two-crew cockpit, facing a sudden dual engine rollback just after rotation, I find it very hard to believe that this two-line exchange was the only interaction captured.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): MAYDAY |