Originally Posted by
areobat
I was thinking cable problem, but not the yolk to elevator cable, rather, the cable the actuates the pin on the elevator lock. If this cable were damaged and/or mis-adjusted, the locking pin may have pulled out part way thus temporarily freeing the elevator mechanism, but after the take-off roll commenced, the vibration, movement, ect., may have caused the pin to re-engage the lock hole thus freezing the elevator. I'm not familiar with the gust lock mechanism on the GIV so I don't know exactly what the failure modes are, so this is a bit of speculation on my part.
That possibility has crossed my mind. However, during my initial maintenance training on the G-IV many years ago, we were told that the hydraulic actuators are capable of producing more than enough force to shear the lock latches right off of their mounting brackets if the associated flight controls are moved forcefully in the cockpit. One reason why the checklist calls for the control lock lever to be released before engine start.
I don't know about the aileron and elevator locks, but there have apparently been several incidents in the G-IVs history of flight crews breaking the rudder control lock by pressing a rudder pedal after engine start with the lock lever still engaged.
Though, that probably would be easy to do, as the rudder has the largest and most powerful hydraulic actuator in the entire flight control system.