I just changed my n-Number. The new n-Number was approved on 21 December. I have already put the new n-Number on the plane, and I want to fly with it, but I read that the ADS-B aircraft identification code that must be programmed into the ADS-B transmiter is tied to the n-number.
When I do an FAA n-number lookup on the new number, it already has a octal code assigned to it, different from the one on the lookup page for the old n-number, (even though the change still shows as "Pending" since I am only today mailing back the FORM 8050-64).

Is this octal code displayed on the lookup page the correct code to be programmed into the ADS-B transmitter? Is there an algorithm or rule to check to verify that this hex code is the right code for my new n-Number?

The new n-Number is N116B, and the hex code is A04296 (or 50041226 in octal)

  • $\begingroup$ Codes look the same. Were you comparing the Mode-S (octal) to the hex code, perhaps? Strangely, just submitted a -64 today as well. $\endgroup$ Commented Dec 29, 2023 at 6:03
  • $\begingroup$ FYI, I called the aircraft registration branch to check on when I can fly her, and all you need to do is keep a copy of the -64 you submitted in the plane with you... you don't need to wait for them to mail back the new registration. In fact, the guy was kind enough to email me a PDF of the -64 so I wouldn't have to wait for snail mail copy to arrive. $\endgroup$ Commented Dec 29, 2023 at 12:14
  • $\begingroup$ I waited for the 64, but you don’t have to take a copy to the FSDO for the airworthiness cert, there’s an online portal for that now. Registration (the 64) still gets mailed. $\endgroup$ Commented Dec 30, 2023 at 14:49

1 Answer 1


In the United States, the ICAO hex code and the tail number are related algorithmically. The code A00001 (in hex, 50000001 in octal) is given to tail number N1, A00002 to N1A, and so on in alphanumerical order (with letters before numbers) up to ADF7C7 for N99999.

You could iterate through all possible tail numbers, but fortunately there's a tool to do this, so you don't have to. If you enter your tail number you'll see that the hex code A04296 (50041226 in octal) is indeed the correct ICAO code.


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