The work of Coastal Command - shots on board a plane as it overflies a merchant convoy.
Full title reads: "Air Guardians of the Coast".
MS and aerial views of Sunderland flying boat taking off in the Solent.
Various good shots of the crew during a mission. with shots of pilot and co-pilot at controls, navigator at work, cameraman filming a merchant ship below and co-pilot using aldis lamp to signal to ships in convoy below, also MS gunners in their positions.