How to Properly Form an N-Number:
N-Numbers consist of a series of alphanumeric characters. U.S. registration numbers may not exceed five characters in addition to the standard U.S. registration prefix letter N. These characters may be:

  • One to five numbers (N12345)
  • One to four numbers followed by one letter (N1234Z)
  • One to three numbers followed by two letters (N123AZ)

To avoid confusion with the numbers one and zero, the letters I and O are not to be used.

Other Requirements

  • An N-Number may not begin with zero. You must precede the first zero in an N-Number with any number 1 through 9. For example, N01Z is not valid.
  • Registration numbers N1 through N99 are strictly reserved for FAA internal use.
  • The FAA no longer issues numbers beginning with NC, NX, NR, or NL. On some older aircraft, these numbers may be displayed in accordance with FAR Part 45.22.