Modern US military aircraft have partial serial numbers painted on their tails. Interestingly, it seems these serial numbers are actually not quite enough to be unique on their own, being comprised of only the year the aircraft was ordered, followed by the last 3 digits (usually) of the serial number. On occasionally this is not a unique combination by itself. Is there a specific combination of tail markings that is guaranteed to be unique? For example, if one combines the branch markings (such as 'AF' for Air Force) and/or the base code (such as 'AZ' for Arizona National Guard), would that be guaranteed to be unique? Thanks so much for any insight.

  • $\begingroup$ Welcome! I'm not sure I understand your question... are you trying to find a way to improve the marking system of the US army? $\endgroup$
    – mins
    Commented Jul 6, 2016 at 19:18
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    $\begingroup$ @mins I don't think he's trying to propose anything. I think he's just trying to figure out how the military deals with the fact that the system can allow two aircraft to have the same markings. $\endgroup$
    – TomMcW
    Commented Jul 7, 2016 at 0:41
  • $\begingroup$ Related: aviation.stackexchange.com/questions/24895/… $\endgroup$
    – Steve
    Commented Jul 7, 2016 at 0:43
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    $\begingroup$ Every combination of painted tail number + aircraft type should be unique. I don't really have proof for it, but because of the number sequencing, duplicates can only occur between aircraft that are so far apart, that they should be easy to distinguish. Feel free to correct me on this, though:) Paint and markings always can change when an aircraft moves to another unit. $\endgroup$
    – Jordy
    Commented Jul 7, 2016 at 7:30
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    $\begingroup$ @Jordy, when you say different aircraft type could be used to differentiate, do you mean different models, or entirely different categories, such as fixed-wing vs. helicopter? Thanks. $\endgroup$
    – Adam Wise
    Commented Jul 7, 2016 at 9:41

3 Answers 3


I can only address the AF system, but I assume the other services systems are similar. The AF serial numbers for vehicles (the system applies to all vehicles including ground vehicles) are made up of the letters "AF" followed by the contracted delivery year (2 digits) followed by a sequential number that restarts at 1 every year. The pic below is of an F-22 assigned to the 1st Fighter Wing (the FF code).

Pic of F-22 tail

So this aircraft was purchased in 2008. The sequence number is 161, and would have been assigned from a block of numbers provided in the contract. The contracting officer was given the block by the office that keeps the master list.

It's worth noting that the paperwork and the data plate is where it has to be complete. What's painted on the a/c is just used for the convenience of the crews. For some a/c such as KC-135's and B-52's whose production run was less than 10 years, they often just us the last digit of the year and the sequence number. Most of the tankers I see have a 5 digit number that starts with 2, for 1962.

In a fighter squadron, most 'local' documentation just refers to the last 3 digits. example: 061 and 813 were how we referenced two of the F-16s in the test squadron.


If I remember correctly, military aircraft do not identify themselves by those painted serial numbers in radio communication. Combine that with the odds of a squadron having two a/c of the same make/model 1,000 serial numbers apart, and the reality is that this is a non-issue.

  • $\begingroup$ I just checked some of my old photos. In 1979 when I was working in a SAR squadron at MCAS Cherry Point the birds used the full BuNo as tail number. But we were different, the call sign of the active bird was always "Pedro". We had a total of 3 birds and they were rotated on the duty. $\endgroup$ Commented Oct 4, 2016 at 12:58

Each service uses its own method.

There's a nice summary of how serial numbers are assigned to military aircraft here.

The US Army began in 1991 to use year/sequence number. Example: 92-00518 Bell-Textron OH-58D(I) Kiowa Warrior delivered in 1991.

The US Navy uses two numbers to identify the aircraft: the Bureau Number, and the side number/call sign.

The bureau number is typically a six digit number that remains with the aircraft/airframe for its entire life, and is assigned once it has been delivered to the government. A given Bureau Number may have different side numbers painted on it, depending upon which squadron it is assigned to.

For example:

An SH-60B Seahawk assigned the bureau number 1613xx would have a two digit side number, typically painted on the forward fuselage just below the door on both sides ... if it was assigned to a West Coast squadron. "Tactical Call Sign Lonewolf 45" enter image description here
If it were assigned to an East Coast Squadron, it would have a three digit side number. (Tactical call sign "Proud Warrior 430") enter image description here


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