Team A has the ball at B's 3 yard line. The QB hands-off the ball to A2; who dives towards the goal line. As a result of the dive, A2 first hits the ground with his elbows at the 1 yard line. It's then the ball pop's loose into the end zone and is recovered and downed by B.
What's the Call?

NCAA Ball became dead when the elbows hit. Wherever the ball was at that moment is what counts. I doubt the ball broke the plane if the elbows were at the 1. Without knowing down and distance prior to the play, can't say what next play will be.

A2 is down at the 1.

4.2.2a states "allows any part of his person other than hand or foot to touch the ground". (EDIT: Dead ball)

WyMike

If we change the play to a pass play, where-by A2 catches the ball in the air and hits the ground 1st with his elbows at B's 1 yard line; when the ball pops loose and rolls in the end zone. Do you have the same call?

Abosolutely. He doesn't possess the ball until he has firm grasp and control and he first contacts the ground. If he looses the ball simultaneously with touching the ground, it is an incomplete pass.

Grasping the ball while airborne by definition is not possession of the ball.