Most experienced officials agree that the most difficult basketball play to get consistently right is the play that involves the dribble driver going airborne and then colliding with the defender in a block charge situation.
What makes this play so difficult to rule on is the fact that the defender is required by rule to obtain legal guarding position the path of the dribble driver before the ball handler leaves the floor. The covering official needs to know when the ball handler left the floor and at the same time know whether or not the defender had established LGP. Almost an impossible task considering those two spots on the floor may be ten feet or more apart.
Many officials who have ruled on scores of these types of plays suggest that the first spot to look at is when the ball handler leaves the floor, then they immediately shift the focus of their vision to the defender. If the defender is still moving at that point the correct call is probably a block. If the defender appears to be completely still the correct call may be a charge. If the play is just to tight to determine and the official is in doubt, more than likely defaulting to a block is the fairest decision because of the safety issue involved with an airborne player.
The clip below shows a bang-bang play that is ruled a block involving an airborne dribble driver. The defender appears to still be moving forward when the dribbler goes airborne. This looks like a correct decision to me on a very difficult play. I would suggest that the calling official not leave the scene of the crime to go report the foul until the players on the floor are separated. Certainly the center official in this clip could have closed on the play much more quickly.
Guarding an opponent with the ball or a stationary opponent without the ball:
a. No time or distance is required to obtain an initial legal position. b. If the opponent with the ball is airborne, the guard must have obtained legal position before the opponent left the floor.