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| sSquares
2025-06-12T18:11:00 permalink Post: 11899557 |
Just a stupid question: Why do they not run the APU during the take-off phase of flight when failures could be catastrophic?
Subjects: APU |
| sSquares
2025-06-12T18:29:00 permalink Post: 11899575 |
The APU might seem to use that much - but the performance of the engines are surely increased as they do not generate aux power any more. One should compare apples with apples.
Subjects: APU |
| sSquares
2025-06-13T12:48:00 permalink Post: 11900479 |
Question is why both engines lost power . Foreign object ingestion , contaminated fuel or both cutoff levels operated ? We do not know .
Any autothrust discussion is misleading since every pilot in that situation will firewall the levers whatever thrust reduction was selected for TO . the same is true for the RAT discussion- if enough hydraulic pressure was generated or not . The plane pitched up last second so there obviously was control until the end . Of course , without energy pulling alone will not bring you anywhere . Why did both engines fail the same second as they would be cut off ??? The "gear-up" places additional load on the hydraulic pumps and the result of that is step increase of load on the generators. Was this the trigger of the failures? Subjects: Fuel (All) Fuel Cutoff Generators/Alternators Hydraulic Failure (All) Hydraulic Pumps RAT (All) |
| sSquares
2025-06-13T17:04:00 permalink Post: 11900697 |
The nose gear angle suggest that the "gear-up" was selected and a dual engine failure happened at the same time, with the hydraulics failing and possible RAT deployment.. The APU was not running and everything, except the flight recorders, might be powered down and restarted at a very low altitude.
Very scary. Subjects: APU DFDR Dual Engine Failure Engine Failure (All) RAT (All) RAT (Deployment) |
| sSquares
2025-06-19T19:05:00 permalink Post: 11906278 |
There were simultaneous engine failures, but those were due to massive birdstrikes (
US1549
) or due to epidemic engine failures on Il-62s of various versions (like
LOT 007
or
LOT 5055
).
Fuel related total engine failures like Aeroflot 366 or Air Transat 236 at least had the decency to have the engines starve one after another as the fuel in the individual tanks depleted. But all those are probably highly irrelevant when considering the Air India accident. An engine disintegration or a heavy birdstrike would have been visible on the videos, a sizeable bird would have left some remains. And gradual fuel starvation would have shown some yaw. As much as I despise the thought, the issue that got AI171 must have come from within the aircraft, although this most decidedly does not infer any wrongdoing by any crewmember.
Not saying it happened here! Subjects: AI171 Engine Failure (All) Fuel (All) Fuel Cutoff Wrong Engine |
| sSquares
2025-06-20T10:59:00 permalink Post: 11906833 |
II.
Fuel-related
1. Loss of electric fuel pumps
Suction feed would have provided sufficient fuel pressure.
2. Fuel contamination
No other aircraft affected, no measures taken at airport. Simultaneous flameout due to contaminated fuel very unlikely.
3. Vapour lock
Unlikely to occur in this scenario. Even if (momentarily) no sufficient fuel pressure from the center tank, the engines would have been fed by the wing tanks.
Subjects: Centre Tank Fuel (All) Fuel Pumps 1 user liked this post. |
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