text: While carrying a Grand Slam, a Lancaster would be incapable of taking evasive action and Fishpond tail-warning radar went with the H2S set. As Messerschmitt Me 262 jet fighters were operating in northern Germany, an Automatic Gun-Laying Turret (AGLT; also, Village Inn or Z Equipment) was considered. The AGLT rear turret had been under test by the Bomber Development Unit and two Main Force squadrons of 1 Group, which found that they restricted the view of the rear-gunner; the radar gun laying device was also unable to discriminate between German fighters and friendly bombers. Bombers equipped with the turret only flew when not in the company of other Allied aircraft. The aircraft of several bomber groups had been fitted with AGLT transmitters which worked best as an early-warning device and the B.Mk.1 (Special)s were fitted with AGLT in the nose. With a fuel load of  the Special would weigh  and the first was delivered to RAF Woodhall Spa, the base of 617 Squadron in Lincolnshire, on 25 February. There were still arguments about what the Specials would carry, when it was found that Avro had failed to install GEE sets. It was agreed to remove the front turret and its accoutrements; heating was needed for the rear guns and the Stabilised Automatic Bomb Sight had Tallboy dropping equipment but no capacity to drop practice bombs, which needed to be incorporated. The TR1154 W/T was to be replaced by VHF R/T.
  Prelude