The Beriev A-50 (NATO reporting name: Mainstay) is a Soviet-origin airborne early warning and control (AEW&C) aircraft that is based on the Ilyushin Il-76 transport plane. Developed to replace the Tupolev Tu-126 "Moss", the A-50 first flew in 1978. Its existence was revealed to the Western Bloc in 1978 by Adolf Tolkachev. It entered service in 1985, with about 42 produced by 1992 when the breakup of the Soviet Union ended production.
