Olive Oil
Keep pressing – it would be a rare thing to get a straightforward answer to a specific relevant question on this thread.
Cazatou
<<The BOI calculated that "it would have been possible for the aircraft to have avoided the ground, whilst remaining on track, from any point beyond the position of the WP change until 4 seconds prior to impact, if the crew had initiated a cyclic climb."
>>
This is an interesting point – just to be clear, a cyclic climb is just pulling back on the cyclic, isn't it? - no thrust lever? I believe that I have mentioned this some time ago, that the power setting as found may have been consistent with the slowing down as calculated by Boeing – and that, if their problem was misjudging their distance to go to that LZ with the intention of landing, then the power setting may have been at a minimum to hold altitude while the speed washed off in that approach – thus there would have been no excess thrust to climb with. Therefore the BOI calculation was wrong.
In the normally agile Chinook, in this case with heaps of power available (with their payload) provided there was time for both engines to spool up, the worst time to need to pull up in a sudden emergency is when you are coasting with the thrust equal to the weight while your speed washes off – you havn't got that component of thrust that was maintaining your speed by overcoming drag to crank upwards in a cyclic climb – you have to pull up on the thrust lever and await the FADEC and turbine lags – any change to the cyclic in that situation without increasing the thrust must result in a loss of altitude.
Had they not been slowing down in an approach to that LZ – had they been maintaining their high cruise speed – they would indeed have been able to pull up suddenly – rapidly gaining significant height - by a cyclic climb.
So summarising briefly, in a high speed approach, to land nicely you need to know your range to go accurately – at the LZ on the Mull, with no room to overshoot, it would have been critical. If you were somehow misled as to your range by so much that you were still in your low power phase washing your high speed off when you realised the error and needed to pull up you would be stuffed – and they were.