The Soviet and its successor the Russian Naval Aviation follow the TOE of the Soviet (Russian Air Force respectively). This practice has been formally established with Order No. 0036 of the Navy Chief-of-Staff (issued on October 7 and implemented on December 15, 1947). Therefore, it followed air force unit convention (air army (air corps) - aviation division - aviation regiment) and its personnel held air force type ranks (generals, colonels, majors etc.). A major divergence from the practice in the NATO member states and the countries, which follow US air force traditions is that the Soviet Union, its Warsaw Pact and other Socialist allies (such as Vietnam, North Korea, Cuba etc.) kept flying units and the ground support units separate (radar, signals, engineer units) subordinated separately to higher command and control level. For example, an aviation regiment and the radar and signals battalion, the air field battalion and the other support units servicing the air field reported to their air division. Another difference is that Soviet military air arms did not bring aviation units of different branches (fighter, transport, helicopter) together. The only exceptions were Mixed Aviation Regiments (which performed liaison and transport tasks for armies, military districts etc. and had a fleet of An-24/ An-26 planes and Mi-8/ Mi-9 helicopters) or rarely air regiments, which flew one single type in different variants and tasks (for example a Tu-22 naval missile-carrying aviation regiment flying 1-2 missile-carrying aviation squadrons and a squadron of reconnaissance or EW variants).