We've picked up a new group of signals

[dkwookie]

I love that Y Wing too. Only thing that bugged me is it has a rotating gun on it that looks perfect for rear gunnery. The rebels missed a beat by making it a one man bomber. A rear facing co pilot would have nailed Darth and his wingman in that trench with ease.
I noticed in Revenge Of The Sith during Obi Wan and Anakins Assault at the start they had cover by Arc fighters. Those Arc fighters do have a rear gunner

Edit found this on Starwars.com
"The initial BTL-B bomber was a double-seater craft with a forward-facing pilot, and a tailgunner in a rotating bubble turret. The Rebel Alliance maintained two basic types of Y-wings, the single-seater BTL-A4 and the double-seater BTL-S3. In the two-seater S3, the gunner sits facing rear, controlling the turret-mounted ion cannon. Both pilot and gunner are protected by a pair of Koensayr ballistic ejection seats that automatically eject both crew members. The A4 features Guidenhauser ejection systems like their X-wing counterparts."

Looks like the Yavin planners had the wrong machines for the death star attack, they needed the BTL-B!