Thanks @ULLS and @Nawrot, i’ve found another way, as my game is in 2D and the fact my question was in relation with the fact “my wish” was to be able to destroy an actor “fireball” when it’s out of the screen.
I’ve simply added around my camera a nice bouding box, and when my fireball “end overlap” the bounding box i destroy this actor taged as fireball !
Again thanks for your time guys !