The problem was identified with the trials of dropping from the boom hatch on the Beverley with the freight bay open for freight drops. The dummies were dropped out of the hatch and disappeared!! They were then discovered in the freight bay!! The solution, eventually, was the design and installation of the "elephant's ears" - spoiler plates attached either side of the freight bay to modify the slipstream. Talking to our 'customers' on various exercises, the majority opinion seemed to be that a Beverly boom exit was much the preferred option giving a comfortable ride.