High School Football

Question
Play late in game knowing there is passing team A drop backs to pass I the umpire move up the ball is released one of my offensive linemen blocking helmet comes off and a B linemen slaps him in the face hand open I throw the flag in the mean time we have a incomplete pass but have defense pass interference ????

Here is want we did--we tried to figure out if my flag was live ball or dead ball which we could not come to agreement on--if we decided it was we were going to give A 15 yards for pass interference and another 15 yards dead ball for personal foul. No one could tell if it was during pass or after the ball came dead. We gave only one foul 15 yards from previous spot made it first and ten started clock on snap since it was incomplete

Answer
Bill thanks for your play.  As I understand your play toy have 2 fouls on B (a UNR-Striking foul and  DPI)

You approached the thought process correctly - you needed to know if you Personal Foul was a live ball or dead ball.  Also I assume you when with a personal foul and not a UNS-fighting foul [B linemen slaps A player whose helmet came off in the face hand open].   Sounds like it is a live ball foul is the ball is still in the air when this occurs.  But since you could not tell it may have been a Dead ball foul occurring ofter the DPI and the pass fell incomplete.  Congratulations on picking up this personal foul as it is a player safety issue.

If I may offer an Umpire mechanics suggestion that may help you on such plays (assuming 4 or more man mechanics): As soon as the pass is thrown and crosses the NZ the Umpire should pivot immediately toward the pass watching to see if the the ball is caught or falls incomplete [the U has the inside out look from underneath or for an inside out look)  if you had done this then you would have known if your UNR was a live ball or dead ball.  If you had thrown your flag before you pivoted it was a live ball foul and if it occurred after you pivoted then the Referee should have gotten the foul and it would have been more likely it was a deadball foul.