N715 is taken. It's currently assigned to a 1954 Dehavilland BEAVER DHC-2 MK.1 registered in Bethel, AK.
See the full aircraft record →A tail number only frees up if the owner deregisters the aircraft or moves it to a different N-number — and even then the FAA holds it before releasing it to the public.
N715 has been worn before. Past registrations from FAA deregistration records:
Tails one nudge away from N715 that aren't assigned or reserved: