Mobile mannequin will help protect aircraft workers

A mobile mannequin that will help safety officers assess the electromagnetic threat to humans flying in or working around military aircraft is being designed for use at BAE SYSTEMS Elecromagnetic test facilities. The mannequin is one of a comprehensive range of techniques used, both for testing equipment and for protecting staff, to be described today (27 June) at the Society for Radiological Protection’s meeting, ’Radio wave exposures’ by Mr Chris Lane, Radiation Protection Officer at BAE Systems, Warton Aerodrome in Lancashire.

Anyone today who travels on an aeroplane or visits a hospital will be familiar with signs asking them not to use their mobile phone, laptop or pocket PC because it could interfere with equipment. How much thought, though, do we give to the possible effects that flying near a TV transmitter mast or over an airfield packed with radar equipment could have on the communications systems or on-board computers of passing aircraft?

Radiofrequency (RF) emissions from transmitters of all kinds can create a range of problems to electronic stystems, from causing interference to navigational aids and communications systems to inadvertently setting off electroexplosive devices installed in ejector seats, weapons systems or the firebottles ready to flood an engine with gas in the event of a fire. Whilst all transmitters have safety barriers to prevent public access (and presumably conform with appropriate legislation), people who accidentally get too near powerful RF signals – from whatever source – could be badly burned by localised tissue-heating effects, suffer heatstress or problems with devices like pacemakers.

Testing aircraft components and navigational aids intended for use in military aircraft against possible RF threats is therefore a vital safety process for BAE SYSTEMS. Getting it wrong can have very serious consequences, as in 1967 when over a hundred people were killed on board the aircraft carrier USS Forrestal in an explosion believed to have been caused when an on-deck radar illuminated a missile on an aircraft.

As well as Warton Aerodrome’s own electromagnetic testing facility – where components are subjected to RF signals to see if they are affected – other on-board system checks which are carried out include placing a full-size human-equivalent dummy in the cockpit and detecting the temperature rise in the body when RF fields are present.

There are also regular RF checks all over the airfield, including monitoring that all equipment confirms with national and international radiation protection guidelines and that there are no time-varying RF effects in the vicinity of fuel stores that could spark an explosion. The implications of possible new buildings and transmitters are also carefully assessed Staff are currently planning to develop a mobile mannequin, fully instrumented with radiation monitoring devices at the wrist, neck and ankles, that they will be able to take round the site and sit in areas where there is a perceived possible risk.