Hi, is it possible to tie down a float plane in fs so it doesn't float away or just keep bumping into the dock ?Thanks.

Probably not but you can always beach it and then just use shift-P to "push it back" again. By "beach it" I don't mean try to run it all the way up onto the beach (unless it's an amphib) but approach the beach with enough way on to get the floats to run up onto the beach a few feet. That's what is done in the rw if there isn't an available dock