Tom is transferred to Mather Field outside Sacramento, California for his “Transition to Medium Bombardment Training.” For him, this means learning to fly the twin-engined B-25 medium bomber.

He had already been selected to be trained as a night fighter pilot (an all-volunteer group), and becoming qualified in the B-25 was the first step in night fighter training. The B-25 was plentiful, had twin engines (like the night fighter planes he would later fly), and there was enough flexibility in the training schedule to favor night flying and instrument flying.

https://youtu.be/M1kQzIolmIc

From: The Army Air Forces in WWII:

The term “transition” was applied generally to a pilot’s learning to operate an unfamiliar plane; thus all students underwent several brief transition phases as they progressed through the normal stages of pilot training. In primary they learned to fly a small aircraft of low horsepower; in basic they transitioned to a heavier plane with more complex controls; in advanced they learned to fly a still more powerful machine which approximated the characteristics of combat aircraft. Transition to combat planes, which generally did not occur until after a pilot had earned his wings, was a larger undertaking than previous transitions to training planes. It involved not only learning to fly a complex, high-performance aircraft, but also the acquisition of flying techniques, preliminary to operational unit training. In order to make adequate provision for this step, a special stage, called transition, was evolved in the major pilot programs.

When the Air Corps’ expansion began in 1939, transition to combat aircraft was a function of the GHQ Air Force and units in overseas departments; the four continental air forces took over this job and carried it on until 1942. By that time the program had become too large for the air forces alone to direct in addition to their operational unit training. Consequently, transition of pilots to heavy and medium bombardment aircraft was assigned to the Flying Training Command, the agency primarily responsible for individual flying instruction. Light bombardment and fighter transition, however, remained a function of the continental air forces’ operational units.25

The time allotted to pilot transition to combat planes varied throughout the war, but by May 1944 it was stabilized at ten weeks for bombardment transition. Fighter pilots received five weeks of transition on obsolescent combat types before being assigned to operational units, where they were given transition on current fighter types prior to tactical training. Transition to the specific aircraft to be flown in combat was the last stage of a pilot’s individual training. Upon completion of this stage, he was ready to start training as a member of an aircrew and a combat unit. Crew and unit indoctrination normally required about twelve weeks, after which the aerial teams were sent to staging areas to prepare for movement overseas. Even though the time for primary-basic-advanced training of pilots was reduced during the war to seven months or less, a pilot was not ready for combat until a year or more after he started flying instruction.26

Upon graduation from advanced two-engine schools, pilots were assigned to transition training on specific combat types. Beginning in 1942, transition for medium and heavy bombardment was conducted by stations of the Flying Training Command; the Third Air Force continued to provide transition for light bombardment as a part of operational unit training. Separate schools were established for each type of airplane; the first of these, for B-17 transition, opened in March 1942. Initial attempts to conduct full combat-crew training at these schools were abandoned in August 1942, and instruction thereafter was confined to transition of first pilots only. An independent program for co-pilot transition was carried on at selected gunnery and technical schools of the Training Command from 1944 to April 1945.38

Until the fall of 1942 entrance into bombardment transition was restricted to pilots with at least one year’s flying experience. When it became necessary to train recent graduates of advanced schools, the instructional period had to be doubled in length; by May 1944 it amounted to ten weeks. Although some differentiation for each type of aircraft was found to be desirable, the flying curricula, each of which prescribed about 100 hours of flying, were generally similar. Instrument, navigation, and high-altitude training received increasing attention in the four-engine schools; formation flying was emphasized in two-engine transition. Toward the end of the war, closer liaison was developed with the combat air forces in order to adapt instruction to the changing requirements of the air war.39

Ground training, from primary through transition, was an essential aspect of the instruction received by AAF pilots, instruction designed to prepare the student for successful performance of flight duties. Although air and ground indoctrination were inadequately coordinated at first, a satisfactory integration was achieved by 1944 through more careful planning of the curriculum and frequent conferences between the teaching staffs of the air and ground departments. Mutual understanding was advanced by encouraging familiarization flights for ground instructors and classroom observations by flying instructors.40