Page 3 - Wartime Airfield Book 1

© 49 Squadron

RAF Fiskerton F.I.D.O. system in operation in 1944

Investigation and Dispersal Operation (FIDO) (which was sometimes referred to as 'Fog Intense
Dispersal Operation' or 'Fog, Intense Dispersal Of′) was a system used for dispersing fog and pea
soup fog (dense smog) from an airfield so that aircraft could land safely. The device was
developed by Arthur Hartley for British RAF bomber stations, allowing the landing of aircraft
returning from raids over Germany in poor visibility by burning fuel in rows on either side of the
runway.

The device consisted of two pipelines situated along both sides of the runway and through which a
fuel (usually the petrol from the airfield's own fuel dump) was pumped along and then out through
burner jets positioned at intervals along the pipelines. The vapours were lit from a series of
burners, producing walls of flame. The FIDO installation usually stored its fuel in four circular
upright tanks built at the edge of the airfield with a low brick bund wall in case of leakage. The
tanks were usually encased in ordinary brickwork as protection from bomb splinters or cannon fire.
When fog prevented returning allied aircraft from locating and seeing their runways to land, they
would be diverted to FIDO equipped aerodromes. RAF night bombers which were damaged on
their missions were also diverted to FIDO airfields due to the need to make certain they could land
when they arrived. When FIDO was needed, the fuel pumps were started to pour flammable liquid
into the pipe system and a jeep with a flaming brand lashed to its rear drove fast down both sides
of the runway to ignite the fuel at the outlets in the pipes. The burners were sometimes ignited by
men on bicycles or by runners on foot. FIDO used huge quantities of fuel, as much as 100,000
gallons per hour.