Fog dispersal

This Air Diagram, an instructional poster produced for use in the training of air and ground crews, dates from the 1940s. It shows FIDO (Fog, Intensive, Dispersal Of) in action.

Fog was such a hazard to RAF aircraft that in 1942 a way of dispersing it was invented known as FIDO. A network of pipes and petrol burners were installed at 15 airfields around the UK. Burning petrol at the rate of 100,000 gallons (456,000 litres) per hour could produce sufficient heat to lift fog enabling pilots to take-off and land safely when poor visibility would otherwise have made flying too dangerous.