Just a desire to gain a better understanding of what happened, why it happened, at what point the maneuver went wrong, and how the resultant crash could have been avoided.
3. I've seen the phrase mentioned on here that the 'Barrel roll' has claimed lots of pilots and is an underestimated manouver, - is there any specific reason why proximity to the ground being an obvious one?
Its quite disappointing reading all the complex chat in this thread because the accident is simply summed up. The pilot crashed because fundementally he didn't understand a barrel roll.
If you are not inverted at the top a barrel roll you will loose height, the problem that causes depends upon how much altitude you have to play with. The solution is simple, you just roll wings level.
As I said its a surprise that this accident happened and perhaps reflects military pilot training.