The Beriev A-50 Shmel (Russian: Шмель 'bumble bee'), (NATO reporting name: 'Mainstay') is a Russian airborne early warning (AEW) aircraft based on the Ilyushin Il-76 transport. Developed to replace the Tupolev Tu-126 'Moss', the A-50 first flew in 1978. It entered service in 1984, with about 40 produced by 1992.
First AWACS aircraft had been inducted to No 50 sq based in Agra on 28 May 2009. According to the revised delivery schedule, second and third ones now expected in 2010. IAF is keen on building up its Phalcon AWACS fleet to a strength of six. AWACS will enable the IAF to carry out tactical surveillance over a radius of 400 kilometers.