Fortress IIA FK185 fitted with an experimental Bristol B.16 nose turret in place of the normal transparent nose
This turret accommodated a 40 mm Vickers ‘S’ gun, which was operated remotely from a position located just beneath the turret. The gun had a horizontal traverse of 30 degrees and an elevation range of 40 degrees. Its primary purpose was to engage surfaced submarines. The altered aircraft underwent firing trials, but it was not eventually put into active service. Subsequently, the aircraft was reverted to its original standard configuration and served with 251 Squadron.