 In 1975 the 1st Squadron (in Dobroslavtsi) transitioned to the outstanding for its time MiG-21MF fighter and declared operational readiness the following year.At the time these events occurred the squadron leader was Georgi Ivanov Kakalov, the country's first cosmonaut.The major re-armament program of the Bulgarian Air Force, started in the 1970s saw the squadron once again converting to a superb fighter type, when a group of pilots and ground engineers went to the Soviet Union (The Operational Conversion Center at Lugovoye, Kyrgyz SSR) for a conversion course to the MiG-23MF in 1978.