A fumble behind the line and a backward passs are considereed a loose ball plays so it is not an a replay beacuse of a loose ball play but because it was a legal kick it is a replay. That is one I always had a hard time with. Here is the rule.
ART. 3 . . . An inadvertent whistle ends the down. Inadvertent whistles are administered as follows:
a. The down shall be replayed if, during a down or during a down in which the penalty for a foul is declined, an inadvertent whistle is sounded while a legal forward pass or snap is in flight, or during a legal kick.
b. The team last in possession may choose to either put the ball in play where possession was lost or replay the down if, during a down or during a down in which the penalty for a foul is declined, an inadvertent whistle is sounded while the ball is loose following a backward pass, fumble, illegal forward pass or illegal kick.
c. The team in possession may choose to either accept the results of the play at the dead-ball spot or replay the down if, during a down or during a down in which the penalty for a foul is declined, an inadvertent whistle is sounded while the ball is in player possession.
d. The penalty shall be administered as determined by the basic spot and takes precedence over inadvertent whistle administration if, during a down, a live-ball foul occurs prior to the inadvertent whistle and the penalty is accepted.
