All-Weather Airfield

All-weather airfields are terms used to describe a runway, that is operable in all conditions of weather such as rain and support low visibility. The term was commonly used during World War II.

By the end of the 1920s, most major cities in the United States had built airports with paved all-weather runways. These airfields consisted of control towers and radio equipment under federal guidance.^[1]

During the invasion of France on D-day, adequate meteorology was required to be recorded prior to air-raids. British and U.S. forecasters predicted a window of brief fair in the English Channel in which the Allied forces attacked. As the war progressed towards the Philippine islands, a mobilisation of boats and planes was required which was susceptible to typhoons and monsoon. By 1945, the United States Army Air Forces constructed 900 weather stations, of which more than 600 were stationed outside the United States. Weather stations were also transferred to operations of The Signals Corp.^[2] In order to build an all-weather airfield, an area must be cleared of trees and other obstructions using machinery such as caterpillar tractors. Once the dirt runway had been leveled, engineers laid pieced steel planking or concrete to create an all-weather runway. Rollers would also smooth out any rough spots left by heavier equipment.^[3]

During all-weather operations for an airfield, aircraft have the ability to take off and land in an airport under low visibility conditions, which means below 550m.^[4] During World War II, all-weather airfields were essential if the region commonly experienced torrential rainfall, and were also fully cleared of obstacles.^[5]

During fair-weather operations for an airfield, it is typically designed to minimize the impact of prevailing winds on aircraft operations, especially for smaller aircraft. The classification is derived from a weather term implying no precipitation and no extreme conditions of clouds, visibility, or wind. During World War II, fair-weather airfields did not have facilities to support low visibility or heavy rain.^[6]

In other countries or air forces, there are different weather or operation terms for airfields.

During the 1940s, an “A” class airfield is applied by the Department of Civil Aviation when there are favorable winds and dry weather. For example, Wittenoom Gorge Airport located in Western Australia, was given this category. ^[7]

According to the Royal Australian Air Force, a B-1 type airfield consists of a gravel runway greater than 800 yards long, and also no permanent facilities. A B-2 type airfield consists of a gravel runway with permanent facilities.^[8]

During the 1950s and 1960s, the Royal Pakistan Air Force classifies airfields into three categories; “A” that receives full maintenance and permanent facilities, and “C” that the runway is to be repaired on notice. Category “C” are commonly used on former RIAF airstrips constructed and abandoned after World War II. Category “B” refers to an airfield that receives maintenance; however, no permanent facilities. For example, the former Chota Sargodha Airfield was classified as “C”, and Miran Shah Air Base as an “A”.^[9][10]