Firefighters are generally associated with fire trucks. But certain fires, particularly wildfires, benefit from the use of aerial firefighting resources.
Aerial firefighting takes advantage of airplanes and helicopters to contain wildfires.
Aerial firefighters, including smokejumpers and rappellers, are specially trained for aerial firefighting service.
As the names suggest, smokejumpers arrive to fires via parachute and rappellers climb down ropes from helicopters.
Airtankers (or water bombers) are airplanes fitted with tanks that can be filled on the ground at an air tanker base or, in the case of flying boats and amphibious aircraft, by skimming water from lakes, reservoirs, or large rivers without needing to land.
Various aircraft have been used over the years for firefighting. In 1947, the United States Air Force and United States Forest Service experimented with military aircraft dropping water-filled bombs. The bombs were unsuccessful, and the use of internal water tanks was adopted instead.
Since then, newer purpose-built tankers have become common and are manufactured in a variety of sizes.
Currently, the largest aerial firefighter is a Boeing 747 aerial firefighter, known as the Global Supertanker, that can carry 19,600 US gallons.
The Global Supertanker is equipped with a pressurized liquid drop system, which can disperse fire retardant under high pressure or drop retardant more slowly at the speed of falling rain.
Using the pressurized system, the aircraft can deliver retardant to the scene of a fire while flying at a height of 400 to 800 feet, at approximately 160 mph.
The Supertanker’s tank system can be configured for segmented drops, allowing the contents of the tank to be released at multiple intervals while in flight. The aircraft is capable of releasing fire retardant over an area 3 miles long and as wide as 150 ft.
Helicopters may be fitted with tanks (helitankers). Alternatively, they may carry buckets. Some helitankers are also outfitted with a front-mounted foam cannon.
Buckets are usually filled by dipping them in nearby lakes, rivers, reservoirs or portable tanks.
Tanks can be filled on the ground (by water tenders or truck-mounted systems) or water can be siphoned from lakes, rivers, reservoirs, or a portable tank through a hanging snorkel.
Water is commonly dopped on fires by planes and helicopters, although sometimes chemicals are added as a thickener to reduce the amount of water draining away from where it is released.
Additionally, foams and gels and other specially formulated fire retardants are used to contain wildfires.
In the past, borate salts were used to fight wildfires but were found to sterilize the soil and be toxic to animals. Newer retardants are not only less toxic but act as fertilizers to help the regrowth of plants after the fire. Fire retardants often contain wetting agents, preservatives and rust inhibitors and are colored red to mark where they have been dropped.
Water is usually dropped directly on flames because its effect is short-lived. Chemical fire retardants are typically dropped ahead of the moving fire or along its edge and may remain effective for two or more days. This can create artificial firebreaks where the terrain is too rugged or remote for ground crews to cut fireline.
“Air attack” may refer to the application of airplanes and/or helicopters on a fire. However, air attack also refers to the supervisor in the air (usually in an airplane above other planes and/or helicopters) who supervises the process of attacking the wildfire from the air.
Depending on the size, location, and assessed potential of the wildfire, the “air attack” may be responsible for the first response of fire suppression, or with the extended attack, which requires the ongoing management of a major wildfire requiring additional resources including fire engines, ground crews, and other aviation personnel and aircraft needed to control the fire and establish control lines or firelines ahead of the wildfire.