saw this on a Fed televised game, 2 & 10 midfield. A1 recieves snap drops back to pass while O line is blocking U throws a flag for B1 (Def Tackle) facemasking an O line member, they call it an inadvertent face mask. Pass is complete to A2 for a 9 yard gain to thier opp 41, what are the options for penalty enforcement, I thought one thing but the WH (I work baseball with) enforced it different thanks!!

That would be a foul be B during a loose play play, assuming the face mask occured prior to the catch. A has the option of taking the result of the play or 5 yard penalty from previous spot. That's how I see it.

I don't work FED, but I thought facemask, even on a player that was not the ballcarrier, was a tack-on (succeeding spot) penalty.

I would tack it on too, at the end of the run, plus repeat the down.

Theres a lot less succeeding spot fouls in fed, it usually occurs towards the end of the run (making the end of run the basic spot) thus from the outside appearing to be a tack on. I think Patton has it on the nose, since it was a loose ball penalty it is enforced from the previous spot.

So if it had been penalized from the end of the run, the down would still be repeated right?

Yes, but it would be incorrect if they are playing FED rules. The run prior to the pass is considered loose ball play for penalty enforcement.

It's a loose ball play. The basic spot for a loose ball penalty is the previous spot. A gets a choice -- 5 yards from the previous spot and replay the down or decline the penalty.

Previous spot is the correct enforcement. It's no different than if a LB held the TE and then the pass was thrown. It's a loose ball foul. It is not a "tack on."

In NF if it was after the catch, or during a running play, you would tack it on and replay the down, but if it was before the catch, it is a loose ball play and enforced from the previous spot.

Roughing the passer, you tack on for a loose ball play.

Canadian Ruling
 

We don't have a 5 yard facemask.

15 yards from the end of the run. Plus an AFD.