That's why Danno is Da Man!!
BUT.....
If the crack goes all the way around, but the part hasn't come off, there may be a wire armature in there. That may make the "snapping" part a bit difficult... If that's the case, and the part cannot be removed, I'd say try to squeeze a bit of epoxy or superglue into the crack, putty the gap with Aves, then paint to match. Just my two pennies.
-Phil