What were all of the above and what did they mean to the Army Air Force’s heavy bombardment groups of both the 8th Air Force operating out of England and the 15th Air Force operating out of Africa and Italy? They were acronyms for a variety of radar navigational systems and methods used for better accuracy while bombing enemy targets during WWII. The inclement weather and the usual cloud cover above the European continent generally obscured the targets of the Bomb Groups, thereby limiting bombing effectiveness. These systems all had varying success stories.

The British scientists developed the initial use of radio detection and ranging (RADAR) for airborne use. American scientists added their skill and knowledge to further improve the bombing techniques and help attain a reasonable degree of accuracy. The end result of the combined effort of the scientists was initially known as BTO (Bombing Through the Overcast) and eventually referred to under the code name Mickey (PFF - Pathfinder Force).

The early techniques used by the Army Air Forces were as follows:

1. British developed “Gee” utilizing an airborne transmitter which interrogated two ground beacons and was used for crude aerial navigation and bombing through the overcast. Gee was very susceptible to jamming by the Germans.
2. Oboe, also developed by the English, was the reverse of Gee in that ground stations interrogated an airborne transmitter and it was somewhat more effective than Gee.
3. The next method used for BTO/PFF bombing was the use of an airborne RADAR set designated as APS15 by its developer, the Massachusetts Institute of Technology. The name used by the Air Force was H2X, or its more commonly used name of Mickey. H2S was the next improvement to H2X.

H2X and subsequently H2S consisted of a receiver and an antenna. The receiver and an antenna. The receiver and antenna were located in the bomber’s fuselage in a housing known as a Radome. The radio compartment of the bomber contained a cathode ray tube along with the necessary electrical equipment needed for its operation. The retractable Radome replaced the ball turret. Langley Field, located in Hampton Roads Virginia, became the first training center for Mickey operators who, on completion of training, were assigned to units of both the 8th and 15th Army Air Forces. Mickeymen quickly became a very scarce commodity in combat areas due to the staggering losses of lead crews. Additional navigators were trained in England at Alconbury. This base was used to provide advanced training as the equipment improved. All Pathfinder-trained crews were assigned to fly as lead for Groups, Wings, Divisions and, of course, the Air Force. The lead aircraft was responsible for navigation to the IP and target and all aircraft would drop bombs when the lead ship dropped its bomb load.

The Mickey operator would work directly with the bombardier by feeding dropping angles to be incorporated in the Norden bombsight optics thus synchronizing the bombsight rate and course by adjusting ground speed, drift and distance to the target. By detuning the set and reducing the gain on the scope, the experienced Mickey man was able to more accurately determine the target blip and get a better read, thereby attaining greater accuracy on the target. Bombing results were improved and the circular error was substantially reduced.

Without the availability of BTO equipment the bombing offensive of both Air Forces would have been greatly curtailed. The Mickey operators were “loners,” in that they were not assigned to any particular lead crew, but flew where or when they were needed.

Transcribed by Raymond J. Borys, 600 Squadron.