United States Military Aircraft Mission Design Series
US Army, US Navy and Tri-Service (Post-1962)

Have you ever wondered what all of the numbers and letters in an aircraft's designation represent? For example, is take a look at the following aircraft: (1) a World War II, United States Army Air Force, North American Aviation B-25 “Mitchell” bomber, (2) a World War II, United States Navy, North American Aviation SNJ-4 “Texan” trainer, and (3) a USAF McDonnell Douglas F-4C-21-MC “Phantom II.”

All three aircraft contain a series of numbers and letters that describe the basic mission of the aircraft, modifications to the aircraft, manufacturer, etc. These numbers and letters represent what the United States Military refers to as the “Mission Design Series (MDS).” The MDS is the official designation for aerospace vehicles. It is used to represent a specific category of aerospace vehicles for operations, support, and documentation purposes. Before we start explaining what everything means, we need to embark on a little history lesson. When military aviation first started in the United States, there were two separate "MDS" systems: one for US Army … USAF, and another for the United States Navy. Both systems were adequate, and evolved as required to accommodate the specific needs of the two military branches. However as time marched on, it became obvious that the United States military needed a common system that applied to all branches of the Armed Services. Therefore, in September of 1962, the United States Department of Defense (DoD) adopted what is commonly referred to as the Tri-Service Designation System. Each of the three MDS systems are discussed via the following links.