Silly txp question

[lolachampcar]

I'm setting up a 261 and need a simple question answered. The FAA site lists my mode s code as 51244231 which converts to 30DECC7 hex. The only problem is that this is one character longer than the set up page allows.

Please forgive the stupid question but am I missing something?

 

[TRCsmith]

Found this online, hope it helps.
" In addition to a national registration number, all aircraft are assigned a unique ICAO 24-bit address or (informally) Mode-S "hex code" upon registration and this international identifier becomes a part of the aircraft's Certificate of Registration. If you have a Mode-S transponder, this code gets programmed into it, and is transmitted to identify your aircraft.

I don't know if the ICAO code is a mathematical encoding of the registration number, or if it is just randomly assigned and the only way to convert one to the other is though a database lookup.

There are 16,777,214 unique ICAO 24-bit addresses available and they may be represented in hexadecimal, octal, or binary format. Online tools such as those at Airframes.org and Kloth.net can match the aircraft's tail number to its ICAO code and return airframe information from the publicly-available FAA aircraft database.

There's more information available on Wikipedia:

http://en.wikipedia.org/wiki/Aviation_transponder_interrogation_modes

Hope this helps!

Reiff"

 

[TRCsmith]

Also read this forum on Mode S codes

"http://www.pilotsofamerica.com/forum/archive/index.php/t-40694.html"

 

[dynonsupport]

The FAA page gives you codes in OCTAL, not DECIMAL.

Thus 51244231 converts to A54899 in HEX.

Page 11-13 of the install guide covers this. You can also go to airframes.org which will give you the answer in HEX directly.

In the USA, your N number and your HEX ID are correlated. You can figure out one from the other. This is not true in most other countries however. Each country gets to assign IDs however they want as long as they are unique.

 

[lolachampcar]

Octal, not decimal. Wow,I would not have guessed that.

Thank you for the help.
Bill

 

[lolachampcar]

I got curious and found the following-

There is an example of a filled out AC Form 8050-64, Assignment of Special Registration Numbers:

http://www.paglen.org/oddsnends/gitmoexpress.pdf

The ICAO aircraft address code is the transponder code represented as 8 octal digits. Note that it only applies to the requested N number, not the aircraft serial number. So for N44982 the octal code is 51267627. To convert it to hexadecimal, convert to 3 bit binary octets and then group into 4 bit Hexadecimal digits.

101 001 010 110 111 110 010 111

1010 0101 0110 1111 1001 0111

A56F97
__________________
Regards,

John D. Collins
CFI, CFII, MEI