Cheers for that Clive - interesting stuff!
Originally Posted by
CliveL
That was indeed so, but #4 was spooled up with the others at 60 kts and the left rudder input from the FDR trace was at 100 kts - no obvious reason for it either.
Us engineers are pre-disposed to be concerned with "why" in that situation, however is it not likely to be the case that a line pilot would simply correct as necessary and worry about the "why" once airborne? After all, the possibility exists that it may simply be an unexpected lateral gust...
Regarding Chris's very salient point, I have to ponder just how significant such vibration would be compared to that which might be expected from a damaged engine as suggested by the warning systems. To my mind this is reinforced considerably by the fact that a trained Concorde flight crew would be acutely aware of just how critical engine problems are during that phase of flight and prioritised that problem almost instantly.