Pilot prepares for trans Atlantic air service , signalling with an emergency semaphore . Pilots of imperial Airways who are to make experimental flights this year in preparation for the proposed trans Atlantic air service are undergoing special training at Hamble , near Southampton . Photo shows , Flight Lieutenant Pascoe , an instructor , signalling to pilots in a flying boat from a dinghy with a special semaphore devised for use in an emergency . 5 March 1936