Its been some time since the GIV, but the other possibilities here:
1. Pitch Trim incorrectly set.
The GIV has the trim setting marked on the trim wheels next to the seats.
A gotcha early on was that the original GIV trim wheel had no "green band" marked on it and it ran from -8 through 0 to +18 (or so from memory). If you werent careful (tired and on a dark night) it was possible at light weights (which equalled low pitch trim settings) to set a negative trim value of -8 instead of +8. Most experienced operators always set at least +10 to avoid this trap - thus ensuring that they have at least +ve pitch trim set.
It seems unlikey that experienced operators would fall for this trap, but me, I can still fall for any trap when its dark and its been a long day.
Later GIVs now have a "green band" marked on the trim wheel that starts at +8.
I have heard stories about this gotcha in other aircraft types causing aborted takeoffs when the aircraft didnt pitch as expected when the yoke was pulled back..
As previously said - the GIV yoke floats back from the forward stops to just short of mid point position from brake release with the combined forces of accelaration and increasing airspeed. That was always the final check of free movement for me.
2. Flight Control Disconnect
Had this happen once on a JAA registered GIV - pilot induced. The JAA GIVs were modified with a mandatory PCU disconnect feature. It was a JAA specific mod and not required or used in an FAA GIV, but something to ask is - was this previously a JAA aircraft with the mod not removed?
A CAS message would have appeared had this occurred.
Last edited by ramble on; 24th Jun 2014 at 22:39.