Tail code

Tail codes are the markings usually on the vertical stabilizer of U.S. military aircraft that help to identify the aircraft's unit and/or base assignment and occasionally other information that is not unique. This is not the same as the serial number, bureau number, or aircraft registration which provide unique aircraft identification.

U.S. Air Force uses multiple codes that relate to the aircraft. Since 1993, all USAF components, including Air Force Reserve and Air National Guard (ANG), utilize this system. Two large letters identify the home base, or in some organizations, an historic legacy, such as "FF" ("First Fighter") for the 1st Fighter Wing or "WP" ("Wolf Pack") for the 8th Fighter Wing. Air National Guard units usually use the two-letter state abbreviation as a tail code, though there are exceptions, such as the 110th Airlift Wing using "BC" ("Battle Creek") instead of the "MI" used for other Michigan Air National Guard units. Individual aircraft are further identified by three smaller numerals that are the last three digits of the airframe's serial number, usually preceded by two smaller digits that indicate the fiscal year that the aircraft was ordered.

All aircraft of all types assigned to a unit, or in the case of ANG units, the entire state, use a common code. In some instances, such as Air Force installations in Alaska (AK) and Hawaii (HH), all aircraft of all components share a common code. Typically, units of different commands co-located at the same base use different codes. For example, the 509th Bomb Wing at Whiteman AFB, Missouri, uses "WM" while the 442nd Fighter Wing of the Air Force Reserve at the same base uses "KC" ("Kansas City").

Air Mobility Command (AMC) aircraft do not use two-letter identification codes, but instead have the name of the base written inside the tail flash. AMC aircraft also use a different standard to identify the aircraft serial number. They use a 5-digit number in which all 5 digits are the same size. In most cases, the first digit represents the last digit of the fiscal year (FY) and the remaining digits identify the 4-digit sequence number. In cases where more than 10,000 aircraft were ordered in a single year (1964, for example), the complete 5-digit sequence number - without FY identification - is used.

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