Fly by wire issue? That would be devastating for the G650 . . .
All I can say, is whatever occurred and why - Gulfstream test flights are fully monitored live time - and this will probably be the one bizjet accident with the most available data ever.
One correction - aircraft was departing runway ‘21’, the starboard wingtip came in contact with the ground on liftoff, the aircraft hit the runway hard - collapsing the gear - one or more fuel tanks clearly ruptured - it doesn’t appear the aircraft hit anything else (other than the ground).
Scary that the aircraft slid from the impact - all the way to the center of the field - narrowly missing the parked airliners. 
