FlightAware Discussions

American Airlines fleet registration numbers

Got a question regarding the registration numbers of the AA fleet. The registration number is on the aft fuselage as normal but there is always a 3 character code on the nosegear door(s) and also on the lower fuselage under the tail. For example, B737-823 is registered N835NN but the characters 3FM are on the nosegear doors and on the aft lower fuselage. Can someone tell me what that “3FM” means, what it is, and if there is any logic to it? Thanks.

It’s the fleet number of the aircraft. It’s used internally instead of the registration.

You can find the fleet numbers at planespotters.net/Airline/American-Airlines by clicking on the number in the last column.

With the number of aircraft that American has it is probably more efficient for them to use fleet numbers rather than registration numbers to keep track of their aircraft. I haven’t looked through all of the registrations for the AA fleet but I have the feeling that their may be duplicate digits (e.g. N321AA and N321AN). Some airlines, such as Southwest, have registrations that contain unique digits throughout the fleet (e.g. you may have a N1SW but NOT a N1WN) so they just use the registration to keep track of the aircraft.

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Truth be told the AA maintenance computer system is limited to 3 characters so…

There’s the tail numeber Nxxxxx and then the Maintenance number (ie 3GY). Carries through mainline and the Envoy planes also.