American Spitfire of the 335th Fighter Squadron 4th Fighter Group pilot Capt Donald Willis
When the first fighter units of the U.S. 8th Air Force began operations in the United Kingdom during World War II, they adopted the RAF’s code letter identification system. This system was initially implemented with the Spitfire V aircraft used by the 31st and 52nd Fighter Groups, which were the first American fighter units to join the 8th Air Force in 1942. The system was later applied to the P-38 Lightnings of the 1st and 14th Fighter Groups.
RAF Code Letter System Overview
Purpose: The code letter system was designed to provide a simple visual identification method for aircraft, both at the squadron and individual aircraft levels, while also maintaining operational security by concealing the identity and disposition of squadrons from the enemy.
Structure:
- Squadron Code: Two paired letters representing the squadron.
- Individual Aircraft Letter: A third letter representing the specific aircraft within the squadron.
- Placement: The letters were typically painted on the fuselage sides, with the squadron code placed before the roundel (national marking) and the individual aircraft letter after it on the left side. This arrangement was reversed on the right side of the aircraft.
- Size and Color: On Spitfires, the code letters were usually 24 inches high and painted in a light blue-grey color known as Sky or duck-egg blue. If this paint was unavailable, a slightly darker shade called Light Sea Grey was used.
Application to U.S. Fighter Units
31st and 52nd Fighter Groups (Spitfires):
- These units were among the first to receive code letter identifications under the RAF system when they were equipped with Spitfire Vs.
- The code letters were applied in the same RAF style, using the prescribed colors and positions.
1st and 14th Fighter Groups (P-38 Lightnings):
- 1st Fighter Group: The depth limitations of the P-38’s twin booms made applying the code letters challenging. The unit grouped all three letters together, 18 inches high, on the radiator coolant cover, often with a hyphen separating the squadron code from the individual aircraft letter.
- 14th Fighter Group: This Group used slightly larger letters in Sky, placing the squadron code on the radiator cover and the aircraft letter on the rear boom.
Operational Considerations
Code Letter Selection: Initially, certain letters like C and I were avoided because they could be easily confused with other letters (e.g., C with G, and I with L or T). However, there was considerable variation in the exact letter shapes used, as official guidelines were not strictly defined, leading to in-the-field modifications.
Security and Efficiency: Although the system was designed with security in mind, it became clear that frequent changes to the code letter combinations were impractical and burdensome. As a result, many squadrons retained the same codes throughout the war, despite the enemy becoming familiar with them. Nonetheless, the system provided a highly effective and efficient means of aircraft identification within the RAF and the USAAF under RAF control.
Unique Adaptations: Some American units, particularly those transferred to the 12th Air Force for Operation Torch, the Allied invasion of North Africa, were not issued squadron code letters because they did not operate under RAF Fighter Command control. This indicates that the use of code letters was specific to units under RAF operational jurisdiction.
Summary
The adoption of the RAF’s code letter system by the 8th Air Force’s early fighter units reflects the close operational ties between the U.S. and British air forces during World War II. The system provided a straightforward and effective method of aircraft identification, even as it required adaptations for different aircraft types and operational needs.