a fall and a trip
 

A1 driving toward basket. B1 guarding but falls and A1 trips over B1 and ball goes oob. whats ur call?

There's no way to make a call based on that description. That's a play you would have to see to make. Could be a foul on B1 or it could be a perfectly legal by B1. It is not automatically either one.

BBR thats just the way it happened. it was JH-8B and sometimes these kids just fall then others trip and it looks real ugly. everyone expects a foul call for a crash. it was difficult to call a block as he was guarding on the move... so i just called oob.

No, that's not "just the way it happened."

Did B1 have legal guarding position?
Did B1 fall down while backing up?
Did B1 move toward A1 as he fell?
Did B1 fall into A1's path as he tried to go by him?

If B1 had not fallen down and the same collision had occurred, would there have been a foul? Who would it have been on?

So no, you did not give us enough information to know whether a foul occurred or not.

yes, yes, no, no

if B1 hadn't fallen down, you could not have the same collision. now if B1 stopped would A1 have run into him? maybe.

B's position is legal (FED rules), so the rest of the play is what it is..

Confucius Say ...
 

There's a difference between being tripped, and tripping.

B may have had LGP, but once he's fallen onto the floor, he no longer has LGP, right? If he moves even a wee bit with A1 falling after the contact with
B1, we'd have a foul on B1, right?

Makes no difference whether he has LGP or not. If he got to his spot on the floor first without illegally contacting an opponent, then he is entitled to that position under NFHS rules. His movement is no more limited than if he was still on his feet.

seems like this has come up several times so far this year (here and elsewhere).....

by NFHS rule, the defender has a right to that space on the floor. When the contact is such that it causes the ball handler to fall and lose the ball, then I've got a foul on the defender.

Whats the rule citation or case?

4-23-1 (3rd sentence) ...Every player is entitled to a spot on the playing court provided such player gets there first without illegally contacting an opponent.

So the defender dives to the floor in front of a dribbler. As long as he gets there before the dribbler, you're not calling a foul when the dribbler trips over the defender?

I've had it happen both ways this year. B1 falls, and lays there while a dribbling A1 trips. No call. B1 trips, and rolls over A1's leg, causing him to fall.

Nope.