RAF Graveley was one of the airfields that was fitted with FIDO (Fog Investigation and Dispersal Operation), which allowed aircraft to take off and land in fog or snow.
A network of pipes was laid along the edges of the runway and in foggy conditions fuel was pumped through the pipes at 100,000 gallons per hour and ignited. The heat generated caused the fog to rise to up to 200ft and the flames highlighted the outline of the runway.
It was first used operationally at Graveley on 19th November 1943 to enable four planes from No. 35 Squadron to land safely.
Further detail from the Graveley Flight Log
Towards the close of 1942, the Petroleum Warfare Department started to install Fido burners 50 yards off each side of the main runway, and for a distance of 500 yards to the East of the runway in the form of a lead in funnel. A pump house was erected together with tankage capacity for 500,000 gallons of petrol. Thus Graveley became the first airfield to be equipped with this new fog dispelling aid.
In January 1943, the first test burn was made and the resultant smoke and flare caused most fire stations within 50 miles to rush to put out the fire; afterwards the mess was cleared of beer in record time.
The first landing made in fog with the aid of FIDO was carried out by F/O N Harding, with the Station Commander BV Robinson as passenger. A/Cmdr. Bennett, A.O.C. Pathfinders, made the first test flight in clear air at night in a Stirling, on the 16th February 1943.
History was made on the night of the 19th November 1943 when four of 35 Squadron’s Halifaxes returning from operations found the airfield covered by radiation fog in which visibility had been reduced to 100 yards to a height of about 50 feet. Within ten minutes of lighting up, FIDO had cleared a lane along the runway in which the equivalent visibility was 2 to 4 miles, while the stars were showing above. The aircraft landed without any difficulty and the Captains – F/Lt Muller, F/Lt Rowe, F/O Jones and Lieut. G. Hoverstad were enthusiastic about the assistance given.
As this was the first time that aircraft returning; from operations had landed in artificially dispersed fog and the Prime Minister had taken a lead in establishing FIDO, Mr. Geoffrey Lloyd, the Minister, Petroleum Warfare Dept., sent a signal to Mr. Churchill who was overseas, informing him of the success of this first operation. In reply Kr. Churchill sent his congratulations to all concerned.
The installation at Graveley enabled some 183 aircraft to land in fog or very poor visibility. Its performance gave great confidence to the the crews.