Fitter2,
Further to your:
I would suggest that any major event similar to the many that have occurred with this aircraft type is highly likely to have required the aircraft to be 'piloted in a manner that is unusual'.
From the HoL Report:
112. Finally, Squadron Leader Burke commented on the rudder input of 77 per cent left yaw found in the wreck of ZD 576:
"That is an enormous rudder input. It is unthinkable to put that in at high speed. As I may have explained, particularly in the Chinook but in any helicopter, the helicopter does not use the yaw input for control once you have gone over 20 knots. It puts an enormous strain on the aircraft because you obtain yawing control in the simplest way by tilting the rotors one left, one right. You are spinning the aircraft about its middle. It is quite difficult to do. The rudder is quite heavy on a Chinook. You have to make a real effort to put that amount of control in. The only conceivable reason that I can think of for putting that voluntarily in as a pilot is if you have partially lost control coming out and you are trying to counteract a yaw one way or the other" (Q 719).
Also interesting from the same part of the report:
108. After Squadron Leader Burke gave evidence, Group Captain Pulford submitted a statement to us (p 68 of HL Paper 25(ii)) in which he sought to explain why Squadron Leader Burke had not been asked to give evidence to the investigating board. He stated that as the Chinook maintenance test pilot "his flying was conducted in accordance with limited and pre-determined flight test schedules and he therefore lacked the operational currency to provide relevant evidence to the inquiry". This reasoning seems to assume that problems which Squadron Leader Burke might have encountered on test would not or could not occur in operational flying - an assumption whose justification we feel to be in doubt.