N400SX is reserved. Fee-paid reservation held by Pekka Karu — if it isn't renewed, the FAA releases it on Jan 21, 2027 (in about 7 months).
Reserved by an individual or company for $10 per year.
Reservations lapse more often than you'd think. Check back around Jan 21, 2027 — if the holder doesn't renew, it becomes available. See everything scheduled to free up in January 2027.
N400SX has been worn before. Past registrations from FAA deregistration records:
Tails one nudge away from N400SX that aren't assigned or reserved: