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Old 9th August 2025 | 22:02
  #20 (permalink)  
PaxLambda
 
Joined: Feb 2024
Posts: 11
Likes: 3
From: France
I hope my question is not too much outside the topic.
Originally Posted by tdracer
Something to remember.
On the 787 (also 777 and 747-8), when the fuel control switch is cycled to CUTOFF, the electrical generation doesn't stop when the engine N2/N3 drops too low - it happens much sooner than that.
In order to facilitate a 'breakless' power transfer during an engine shutdown, the fuel control switch sends a signal to the electrical system, which reconfigures to drop the related generators from the system before they drop off line. This takes ~0.25 seconds, not the several seconds it takes for the N2/N3 to drop sub-idle.

So in the case of the Air India 787, the system would have lost all main-bus power generation a fraction of a second after the second fuel control switch was moved to CUTOFF, commanding the RAT deployment.
If all main-bus power was lost around 08:08:43, how is it possible there were FR24 ADS-B transmissions with time stamps until 08:08:51?

PL
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