Using aircraft to help fight firesOver the past three decades the DEPI has developed a formidable aerial firefighting service to control wildfires in vast areas of often inaccessible and rugged country. The fleet of fixed wing aircraft and helicopters represents one of the most comprehensive and cost effective firefighting support fleets in the world.
DEPI has a formal arrangement with the Country Fire Authority (CFA) for supply of helicopter services to the CFA. An Integrated Firefighting Aircraft Resource (IFAR) arrangement provides one set of specialised firefighting aircraft for Victoria, as well as putting in place some standard management systems and support arrangements for all aircraft used in fire suppression across Victoria.
Aerial Suppression is used for ‘first attack’ in cases where the fire is inaccessible or has potential to spread significantly before ground crews have time to travel to or contain the fire. On larger scale wildfires, aircraft may play a large part in helping control the fire as part of the firefighting contingency.
Aerial Suppression involves aircraft using water, retardant or foam to control the fire or (to) construct control lines ahead of the fire. A light fixed wing aircraft or light helicopter is used to guide the fire-bombing aircraft bombers into their drop points.
Fixed Wing BombersTen large agricultural style aircraft make up DEPI’s fixed wing fleet. These aircraft carry up to 3 200 litres of fire retardant slurry or foam. These aircraft are generally the most cost-effective firebombers for the Victorian situation. Their robustness and power enables them to work from short, less sophisticated airstrips that are numerous across Victoria, whilst still delivering good loads of fire retardant mixtures. The larger agricultural aircraft are able to deliver the retardant to the fire at a lower cost per litre than other aircraft.
Fixed wing firebombers have different applications to firebombing helicopters. The helicopters are the most cost-effective solution when water is nearby, and turn around times are short, or maybe where a rappelling crew requires some support. Fixed wing firebombers are most effective in situations where water is hard to find, the fires are remote or in the situation where there is multiple fires - such as often occurs after a lightning storm.
DEPI maintains a Statewide network of 15 firebombing bases, which are made up of an airstrip, water supply and equipment for mixing fire retardant. In addition to fixed retardant bases, a number of mobile retardant mixers are located across the State.
The fire retardant normally used is a slurry of water and sulphate fertiliser. This mixture is very effective at slowing or stopping the progress of fires.
DEPI’s fixed wing firebombers are also capable of dropping a foam-water mixture onto the fire. The solution, basically a biodegradable detergent, causes the water to foam as it exits the aircraft. Foamed water is up to three times more effective at suppressing fires than water without foam. Retardant slurries and foam solutions have different applications in firefighting. In general, retardant is applied on remote forest fires and is sometimes used to assist backburning operations. Foam is most often used in direct support of firefighters working on the fire, or in direct aerial attack of fast moving grass fires. Strict human health and environmental risks govern the use of these retardants and foams. DEPI participates in national and international forums that regularly monitor developments in relation to the use of these materials. See Also Research Report 50
PZL M18 Dromader Firebombing Aeroplane
There are five M18 Dromaders, as part of the fixed wing aeroplane fleet. Built in Poland, the Dromader is a large agricultural aircraft specially modified for fire related work. It carries 2,500 litres of fire retardant and has a specially designed firebombing door allows the load to exit the aircraft in about two seconds.
Air Tractor 802 Firebombing Aircraft
The AT802 is the largest capacity firebombing aircraft currently on contract in Australia and is unique in that it is designed specifically for firebombing, unlike other agricultural type firebombing aircraft, which are modified for fire related work.
The AT802 is built in America and carries 3,200 litres of fire retardant or foam solution. Powered by a 1400 horse-power Pratt & Whitney PT6 turbine engine, the aircraft has a cruise speed of approximately 160 knots or 300 km/h. The specially designed computer controlled firebombing doors which run parallel with the longitudinal axis of the aircraft allow the load to exit the aircraft in less than two seconds, and offer infinite variation in drop options.
The Aerospatiale Squirrel (AS350) is a turbine-powered light utility helicopter capable of carrying five passengers and, along with Bell Jetranger 206BIII helicopters, performs a number of important roles in firefighting and resource management in Victoria. The Squirrel and the Jetrangers make up a fleet of four light utility helicopters located across Victoria at strategic locations.
Main functions of the light utility helicopters include:
- fire detection and mapping,
- aerial reconnaissance,
- aerial command over the fire area,
- carriage of Forward Looking Infra-Red (FLIR) units,
- backburning with aerial incendiary machine, and
- limited firebombing with underslung bucket.
DEPI operates up to five medium class helicopters (such as the Bell 205, Bell 212 or Bell 412) for aerial firefighting.
The main functions of the medium class helicopters are:
- rappelling of fire fighters into remote, or inaccessible areas,
- bombing fires with water or fire retardant foam solution, and
- transporting of fire fighters and heavy stores at remote fires.
The concentrate, which is essentially a biodegradable detergent, causes the water to foam up as it exits the tank during bombing. Foamed water is around three times more effective at suppressing fires than water without foam.
The bomb doors on the underside of the tank can be opened in various different combinations - allowing adjustment of the bombing pattern to suit the particular situation.
Air Crane Helitanker (Erickson S-64F)
The Erickson S-64 Air Crane Helitanker is a heavy lifting helicopter with a large capacity fixed tank attached to the under body of the helicopter’s fuselage. The tank holds 9000 litres. The helitanker has the versatility of a helicopter with the added value of delivering a large volume of fire suppressant.
The helitanker’s fixed tank has a constant flow system with a single long, narrow door operation designed to be used with water, foam injected into the water from a separate internal foam storage tank.
The helitanker has the ability to self-fill by lowering a snorkel into a suitable water source. The minimum depth required for the snorkel operation is 0.5 metres and a clearance diameter of 60 metres around the water source is required to allow safe access. The filling system has the ability to draw 9000 litres in 40 seconds.
The helitanker normally drops its load of fire suppressant at a speed of 45 knots. This slow speed delivery allows for direct application of the suppressant onto the fire edge. The helitanker is capable of making multiple drops where the pilot can select the volume of each drop providing a variety of options for suppressing wildfire.
Air Crane Helitanker Facts:
Maximum Speed 100 Knots
Length 27.3 metres
Height 7.82 metres
Main Rotor Diameter 22.0 metres
Tank Capacity 9,000 litres
Hover Fill Time 40seconds
Fuel Consumption 2,080 litres per hour
Foam Capacity 290 litres
When the Air-crane is dispatched to a wildfire it is supported by essential ground resources, a fully pressurized refueling truck containing 30,000 litres of Jet-A1, one of three strategically based (DEPI work centres) mobile foam support units and an engineering maintenance team.
If the Air-crane is deployed to a fire consideration must be given to identifying landing areas suitable for refueling and refilling of foam. Suitable areas are large sports ovals with limited development around the perimeter so as to minimize rotor wash effect and minimize dust. In addition the landing areas will require provisions for restricting public access for safety purposes.
Ground firefighting resources working in conjunction with Air-crane or any fire bombing aircraft are to observe and maintain awareness of the standard drop zone safety procedures and be aware that the Air-crane has the option of providing multiple high volume drops in one load.
Hover Exit and Rappel CrewsIn remote areas of Victoria ground based transport of personnel and equipment to a fire can often take many hours by both vehicle and foot. DEPI has developed two methods of deploying firefighters and specialist equipment from helicopters, enabling speedy access to fires in remote areas of Victoria. Rappelling and hover exit are the terms used for these deployment methods.
The DEPI firefighters trained in these procedures will upon arrival at a fire, make an assessment of its potential and if possible take direct suppression action. They may request support from firebombing aircraft or additional rappel/hover exit crews. If the fire is beyond their resource capability, the crew may prepare a helipad nearby to enable the transport of additional DEPI firefighters and equipment to the fire area by helicopters.
In simple terms, rappelling is similar to abseiling down a cliff or wall. Using specialised equipment (similar to that used by abseilers), specialist DEPI firefighters ‘abseil’ or rappel down ropes from a hovering helicopter to the ground. This technique enables DEPI to access fires specifically in the remote forest/wilderness areas of Victoria where generally no clearings are available to land helicopters.
Once the crew has rappelled to the ground, specialised firefighting equipment is lowered from the helicopter to the ground. The helicopter is also equipped with a belly tank or bucket which can be used to assist the ground crew by bombing the fire with water or foam.
Rappelling trials were first conducted by DEPI (the then Forests Commission Victoria) in 1964 from a Bell 47G helicopter. Rappel operations were conducted by a two man crew based at Heyfield for the following two fire seasons. DEPI rappel operations re-commenced in 1982.
A rappel crew comprises a crewleader, rappel dispatcher and five crew members. All crews are fully self contained with specialist firefighting and support equipment. The maximum height for a helicopter rappel is 100m and DEPI rappel operations are currently only approved from Bell 205/212/412 helicopters.
DEPI currently has four, seven person rappel crews employed during the fire season (December to April), based at Bairnsdale, Benalla, Heyfield and Myrtleford for operations in the forested and Alpine areas of Gippsland and North East Victoria.
The dispatch of rappellers and equipment from the helicopter to the ground is very strictly supervised by the rappel dispatcher who is trained and endorsed as a helicopter aircrewman. The dispatcher remains in the helicopter and is constantly in communications with the helicopter pilot. Once suppression of the fire is complete the rappel crew must walk out to a pick up site with their equipment.
This deployment method is primarily designed for areas where ground vegetation or terrain prevented a helicopter from conducting a full skid landing. In Victoria this is ideally suited to the High Plains, heath areas of the Deserts and scrub/rock areas of the Grampians.
Hover exiting is the transfer of trained personnel and equipment from a hovering helicopter to the ground - it is very definitely not ‘jumping’ from the skids. Hover exits can only be conducted by specially trained DEPI personnel and can only be conducted from a maximum height of 1.3 metres.
The hover exit technique was originally developed in British Columbia, Canada and has been modified by DEPI to suit local conditions with the formation of operational hover exit crews in 1991.
Personnel employed on rappel and hover exit crews are required to meet specific pre-selection criteria including height and weight restrictions, and fire and bush skills. Specialised training is conducted by DEPI staff prior to the commencement of each fire season.
Aerial Mapping SystemsAircraft are used for a variety of purposes in fire management operations. This includes the use of aircraft to map fires and locate ‘hot spots’ at fire events.
Airborne Infra-red Scanner
An Infra Red Line Scanner, mounted onto a Cessna 404 aircraft, is used to detect and record fire activity by sensing infra-red radiation generated by the fire. The scanner also records background infra-red information such as terrain, streams and roads, allowing pinpointing of the location of fire edges and burnt out areas. As infra-red is able to ‘see’ through smoke, it has particular application where smoke or haze prevents mapping or information gathering by other means. Primary firefighting applications for the scanner include:
- obtaining information at remote or inaccessible fires, at fires where smoke or haze is a problem, or where it is useful to obtain information at night,
- obtaining information on, and mapping, very fast moving fires - this can be done in an ‘tactical’ mode where the information is immediately able to be used in directing firefighting strategies,
- monitoring the effectiveness of fire control strategies such as backburning, and
- detection of ‘spot overs’ during control activities.
- radio facsimile link using the aircraft's on-board facsimile machine,
- radio transmission of the ‘Firescan’ digital data files,
- landing at a nearby aerodrome and handing the maps or images to fire control staff, dropping maps, prints or computer disks at a pre-arranged location.
Digital data files transmitted to the ground may also be further processed or enhanced, or fed into DEPI’s Geographic Information System to generate complete fire control plans and predictions.
GPS Based Automated Real Time Mapping Systems (ARMS)
Automated Real Time Mapping (ARMS) was developed by DEPI and Global Star, to automatically map the location and boundaries of wildfires. ARMS is also now used in a wide range of applications.
ARMS is normally used in helicopters but works well in any aircraft or vehicle. The ARMS kit combines a Global Positioning System (GPS), a small notebook style computer and printer, along with uninteruptable power supplies, into a rugged highly portable case. Any aircraft equipped with an ARMS kit may be flown along the fire edge while the ARMS software records the track of the aircraft using GPS information. This track then represents the fire boundary. As the aircraft is flown, notes and annotations such as location of resources and problem spots may be added to the data file. Logging of the track may be turned on and off, if for example it is necessary to make a detour. The computer also displays the progress of the helicopter on the screen, in real time graphical display, complete with grid reference information.
The fire outline is automatically referenced to the Australian Map Grid (AMG). The ARMS software will also display current position in terms of popular street directory and map book references, and latitude and longitude, as well as providing AMG references, including mapsheet name and number, at various scales.
Running under Microsoft WindowsTM , ARMS has been designed to be straightforward and simple to use. The usual output from the system is a transparent overlay, printed to scale, showing the fire boundary and the notes and annotations. The overlay automatically includes mapsheet names and grid reference points, allowing it to be directly placed over a normal topographic map. This overlay may be produced on board the aircraft.
The ARMS kit may also include modems, which allow the information to be transmitted via radio or by phone or fax and printed out on the ground. The data may also be transmitted over any normal data network. The fire outline produced is also in a suitable format for the inclusion in most GIS systems, for overlay and further processing is required.
Forward Looking Infra Red (FLIR)
Forward Looking Infra Red (FLIR) units are much like sophisticated video cameras specially designed to detect and record infra red energy instead of visible light. In effect this gives these cameras the ability to detect heat. Temperature differences of as low as 0.20C can be detected by most FLIR units.
DEPI operates FLIR equipment for firefighting and various other applications. As thermal energy is able to pass through smoke, the FLIR units are effectively able to “see” through smoke – providing information that greatly assists firefighting operations.
For fire operations the FLIR units are normally mounted on one of DEPI’s ‘light’ helicopters, such as the Aerospatiale Squirrel, although they may also be mounted on fixed wing aircraft. The output is displayed to the observer on a video monitor inside the aircraft cabin, and is also recorded on conventional VHS videotape. The aircraft’s position, determined by satellite navigation, is also displayed on the monitor and recorded on tape.
The information is particularly useful for:
- mapping fire edges,
- directing firefighting crews to trouble spots,
- directing firebombing aircraft and assessing the effectiveness of their drops, and
- detecting fire ‘hotspots’ during mopping up operations.