In 1946 the Society was required to transfer its aircraft and trained personnel to the Aviation Section of the Pyongyang Military Academy. Soviet-trained Korean officers were placed in positions of responsibility under the command of Colonel Wang Yun, a former captain in the Soviet air force who replaced Lee Hwal. The Aviation Section numbered about 100 officers, 250 enlisted men and 500 students by November 1948. Estimates of aircraft are contradictory, but one source reported 7 Japanese trainers, 6 Japanese fighters and a Japanese twin-engine transport. Shortly afterwards the first Soviet aircraft were received, and the NKPA Air Force was created from the Aviation Section and moved to the Pyongyang air base. The final phase of development came in January 1950 with the expansion of the air regiment into a division under the command of Wang Yun, promoted to major general. Strength of the unit in April 1950 was estimated at about 1,675 officers and men, including 364 officers, 76 pilots, 875 enlisted men, and 360 cadets. The receipt of more Soviet planes at this time brought the number of aircraft up to 178, including 78 YAK-7B fighters, 30 PO-2 primary and YAK-18 advanced trainers, and 70 Il-10 ground attack bombers. Captured documents indicate that the aviation training program was speeded up along with other NKPA activities during the last few months before the invasion. In June 1950 each pilot was required to fly 40 training missions and attend 40 hours of lectures. As preparations for the invasion neared completion, a forward displacement of tactical aircraft was put into effect.[34] [34] _Ibid._ The North Korean armored division, a copy of its Soviet counterpart, had only about half of the overall strength. Thus the NKPA 105th Armored Division, comprising some 6,000 officers and men, included 3 medium tank regiments, the 107th, 109th, and 203d, with 40 tanks each. Organic supporting units were the 206th Mechanized Infantry Regiment and the 308th Armored Battalion equipped with self-propelled 76-mm. guns. POW reports also mentioned reconnaissance, engineer, signal, ordnance and medical battalions and a mixed unit identified as the 849th Antitank Regiment, attached to the division after the invasion started.[35] [35] FECOM, ATIS, _Enemy Forces_, _op. cit._, 27–32. All reports indicate that the division was split in combat, with each tank regiment being assigned to an infantry division. Even the training of the regiments had been conducted separately, and there is no evidence of prewar maneuvers on the division level.