The BTL-S3 was a two-man strike fighter, and was the most common Y-wing configuration. The weapons systems officer typically operated the ion cannon turret when needed.
Luke Skywalker used this variant on his mission to Panna in 0 ABY, as did Leia Organa and C-3PO on their journey to the Circarpous system. Twelve of these variants, piloted by Bothans sympathetic to the Rebellion and Alliance pilot Ace Azzameen, participated in the capture of the Imperial freighter Suprosa during the First Battle of Bothawui to steal a supercomputer containing the plans to the second Death Star.
Many Y-wings of this variant were modified with defensive rapid-fire blaster turrets replacing the ion cannon turret and particle cannons instead of the dual laser cannons on the nose. These Y-wings were used as heavy capital ship destroyers, and were eventually phased out by the new B-wing starfighters.[source?]