Aerial Fire Control

There are a number of powerful aerial fire control techniques to support ground control operations when needed, although most fires do not require aerial assistance. Every year, thousands of initial attack fires are suppressed without the need of aerial support. Others may be suppressed without aircraft use because of flight distance or unavailability. Aircraft used in fire operations include air tankers, lead planes, infrared reconnaissance planes, and helicopters.

Air Tankers

Air tankers are large planes equipped with tanks for transporting and dropping fire retardant (e.g., diammonium phosphate) or water in order to slow a fire down in support of fireline construction operations on the ground.  Air tankers are primarily used for initial attack and structure protection. Typically a red dye is added to chemical retardants to provide pilots with visual markers of drop accuracy. Capacities range from 2,000 to 3,000 gallons, although feasibility tests have been conducted for larger capacities (e.g., a 747 jumbo jet). Single engine air tankers have less capacity but greater mobility, an added advantage in mountainous areas.

Airplanes have been used in firefighting operations since 1915, when an experimental Navy amphibious aircraft was first used for fire detection purposes in the forests around Puget Sound. By 1926 airplanes were used to drop supplies to firefighters on the ground. Smokejumping in the US started in 1939. Widespread use of air tankers with retardant-drop capabilities was adopted in 1954, following feasibility studies initiated in World War II (Chandler and others 1983).

In the United States many aircraft are either surplus from the military or date from World War II vintage supplies, including helicopters, air tankers, modular airborne fire fighting systems (MAFFS), lead planes, and infrared aircraft (Omi, In Press). Most airplanes are leased by government agencies from private contractors who convert former military aircraft to carry and deliver fire retardant. Over time, concerns have been expressed about the costs of overhauling old airplanes, including finding parts. The aging US air tanker fleet (44 ships in 2002) caused great alarm, especially with two fatality accidents in 2002, involving planes that broke apart in the air while delivering retardant to fires. The planes involved in crashes that year included a World War II era PB4Y-2 that broke apart near Estes Park, Colorado in July 2002 and a C-130A air tanker whose wings separated from the fuselage in June 2002 near the town of Walker in eastern California. The planes involved were 57 and 46 years old, respectively. Fatigue cracks were found in the wings of both planes by investigators from the National Transportation Safety Board (NTSB). At one point the entire USDA Forest Service fleet was grounded following the second crash.  Later, the government permanently banned the use of the PB4Y-2 and C-130A aircraft for firefighting use.

Depending on locale (i.e., proximity to large water bodies), some US agencies have increasingly relied on the Canadair CL 215 and the larger CL 415 aircraft. These planes offer advantages because of their ability to scoop water from a lake or sea for subsequent drops on land. Also, airworthiness is documented and supported by Canadair.

Air tankers seem to attract controversy because of their high visibility and cost. Cynics speak of “political retardant” in reference to planes that are called into action when they are not needed, appealing instead to influential politicians and a public that wants to see agencies taking action against a fire. On the other hand, years of usage have verified the usefulness of dropping freely cascading liquids onto fire hot spots, especially where crews on the ground have access to follow up the drop with line-building activities. In reality, the truth lies somewhere in between these two extremes: on some fires, air tankers are extremely helpful in helping firefighters on the ground to gain the upper hand on a wildfire, while on others their excessive use may be a waste of taxpayer monies.

In May 2004 the federal government decided to terminate the contract for the 33 fixed-wing large air tankers still operating within the firefighting fleet, after the NTSB released a report of findings following the fatality accidents. The report found no effective mechanism for ensuring the continuing airworthiness and safety of these older ships, concluding that the older aircraft posed an unacceptable risk to contract aviators, firefighters, and the general public. The contract cancellation did not apply to the 80 single engine air tankers, and eight military C-130 E and H model aircraft equipped with MAFFs, whose responsibility for airworthiness is the responsibility of the military.  The termination of the air tanker contract essentially ended a colorful and controversial chapter in the history of firefighting in the US.

Lead Planes

Lead planes are smaller, mobile airplanes used to provide reconnaissance of burning areas from above and guide air tankers to desirable drop locations.

Infrared Reconnaissance Planes

Infrared reconnaissance planes are small airplanes equipped with specialized infrared mapping systems for detecting hot spots inside and outside a fire perimeter. Highly sensitive scanners are able to detect heat with a high degree of accuracy (6 inches spot from 8000 foot elevation). Geographic referencing of hot spots via global positioning systems (GPS) provides useful reconnaissance information. Cobra attack helicopters with Forward-Looking-Infrared detection capabilities linked to a GPS can provide online-video capability. In contrast to the fire lookout, which provides constant surveillance of a fixed geographic area, the aerial platform provides intermittent, yet flexible coverage over a much larger territory (Chandler and others 1983).

Helicopters

Helicopters provide cargo and personnel support for firefighters working a fire perimeter.  Helicopter can slow a fire spread by dropping water, foam, or retardant on burning trees, shrubs, and structures. Large helicopters carry up to 2000 gallons of liquid.  Medium and light helicopters have lower capacities, down to 300 gallons or less. Helitack crews can rappel down to fires in remote areas. Helicopters are also valuable for conducting large scale firing operations on wild- and prescribed fires.

Helicopters used on fires include the heavy lift Erickson helitanker, military style UH-1 Hueys, Kaman-built K-Maxes, Bell Rangers, several Sikorski models, and Boeing-built Chinooks. Payloads vary from 600 to 1000-gallon buckets filled from tanker trucks or water springs to the 2600 gallon detachable tank on the helitanker that can be filled in 45 seconds from a lake or deep hole in a river (Enders 2001).