A 3/7 A 33. A1 drops back to pass. While A2 is running his pass route, B3 blocks him to the ground at the A40. A1 still has the ball at this point and throws a forward pass to A2, but the pass is intercepted by B3 who runs it back to the A 28. After the play is blown dead, A4 hits B4 with a shot to the helmet.

Ok.. will take a shot at this one.

B3's contact is not pass interefernce as B's restrictions do not begin unitl the ball leaves the passer's hand. It may however, be ruled illegal contact-personal foul on B3 during a loose ball play. Spot of enforcement is the previous spot and penalize B 15 yards from A33 to A48 and A is awarded a first down by attaining the line to gain. A is then penalized a dead ball foul by A4. A will be penalized 15 yards from A's 48 back to A's 33. It is first down and 10 from A's 33.

Canadian Ruling
 

This is not a dual foul.

We have illegal contact by the defense and dead ball UR by the offense. Up 10 for the ICER which gives, A 1D/10 @ A-43. Then back 15 for the UR. A 1D/10 @ A-28.

Obviously B did not get the ball with clean hands, so they will not get the ball. It is not an illegal contact foul, as it does not meet the definition. It is an illegal use of hands foul in both NF and NCAA. That is a 10 yard penalty from the PS, and it would be a 1st down for A since the LTG was reached. You would then enforce the DB PF against team A taking the ball back to the 28, where it would be 1st and 10 for A. A4 should be ejected as well.

Thanks. I had the ball and down and distance correct but forgot all about the disqualified player.

You could argue that the block on A2 is legal if he qualifies as a "potential blocker." We had this discussion in another thread a while back. If A2 isn't presenting himself as a blocker, then you would flag B for Illegal use of hands, 9-2-3D. Sit 9.2.3A covers a situation similar to this (2004 Fed books- haven't received 2005 yet :( )
Then from here I agree with MJT, but depending on the severity of the hit, A4 might not be ejected.

Agreed
 

I agree, but since the plays says A2 is 'running his route' I'll assume that he's no longer a potention blocker.