Aerial Firefighting

Who is responsible for aerial firefighting in Australia?
The responsibility for suppression of wildfires (bushfires as they are known in Australia) rests with the Governments of each of the Australian States and Territories. Each State and Territory Government has one or more agencies that are responsible for bushfire prevention and suppression. Where it is safe, efficient and cost effective to do so, most States and Territories utilise aircraft to support their fire suppression and other fire management activities. Most firefighting aircraft are chartered from appropriately experienced and qualified commercial aircraft service providers. A small number of aircraft are owned and operated by Australian fire agencies. For more information on the individual agencies involved in fire in Australia visit the Australasian Fire and Emergency Service Authorities Council at The State and Territory agencies involved in firefighting and land management recognise that improved performance, cost savings and other synergies may be obtained through cooperation and sharing of resources and support systems between States and Territories. This is especially so for expensive, highly specialised resources such as firefighting aircraft. That is where NAFC comes in – the aim is to facilitate resource sharing and cooperation between agencies across the country.

What are the aircraft used for in fighting bushfires?
Aircraft undertake a wide range of valuable support tasks, including:
· Firebombing – the dropping of water, or foam or fire retardant slurries on, or in front of the fire, to reduce or halt the spread of the fire;
· Rapid delivery of firefighters to remote areas by rappelling or winching;
· Fire detection, reconnaissance and mapping (including with highly sophisticated infra-red sensors;
· Command, communications and control;
· Transportation of firefighters and equipment; and
· Aerial ignition – dropping of approved incendiary devices to ignite backburns or planned fuel reduction burns.

What types of aircraft are used?
A wide range of fixed-wing and rotary-wing aircraft are used to support fire operations. Aircraft are selected for individual tasks based on their suitability for the task and their cost effectiveness.
Larger helicopters are most often used for firebombing and crew transportation, whilst smaller helicopters are more often used for command and control, mapping and aerial ignition.
Fixed-wing aircraft that are used for firebombing tend to be of the larger agricultural-style, specially modified for firebombing. These aircraft are sometimes referred to as SEATs (Single-Engined Air Tankers). This type of aircraft particularly suits the conditions most often encountered in Australia where there are relatively few long paved runways, but plenty of agricultural airstrips. Larger fixed-wing aircraft have been used where appropriate and cost-effective. Light fixed-wing aircraft are also regularly used for fire detection, reconnaissance, command and control.

What is dropped from aircraft to fight bushfires?
It could be water, Class A foam, a gel or retardant. The Air Attack Supervisor for a bushfire incident will assess the situation and decide what will be the most effective approach for that particular situation. Water is only used when there can be a very quick turnaround – this is normally the province of helicopters that can re-fill themselves while hovering over a nearby water source. Water is applied directly to the fire. Class A foam, or bushfire fighting foam, is somewhat akin to a detergent. It is added to the load of water in a helicopter or fixed wing aircraft. As the load leaves the aircraft the shearing action of the airflow causes bubbles to be formed – in a nutshell this improves the smothering effect of the water, allowing it to be more effective and to remain on the ground for a longer period. Class A Foam is applied directly to the fire. Retardant is a slurry – with a similar consistency to tomato soup – that contains mainly water and high-grade ammonium phosphate or ammonium sulphate (as are commonly used in agricultural fertilisers). The retardant is laid ahead of the fire and coats the fuel (leaves, twigs and bark etc) on the ground. As the fire burns into the coated fuel a chemical reaction occurs and this effectively retards the fire. The main advantage of retardant is that it remains effective for some time after it is dropped. As well as water, only approved Class A foam and retardant products may be dropped from aircraft in Australia. Australian agencies utilise the Wildland Fire Chemical System of the United States Department of Agriculture.

Can you use sea-water?
Most firefighting aircraft are capable of dropping either salt or fresh water. However, for helicopters that are equipped with bellytanks that use hover-fill pumps, or with buckets on ‘short’ lines, we do tend to prefer to use fresh water if possible. This is to avoid the chance of ingesting salt into the turbine engines, and into some particular parts of the airframe that are susceptible to corrosion – all of which requires substantial extra maintenance at the end of the day. However, in an emergency, any suitable water supply will be used, including sea water, and the extra maintenance will be undertaken. For helicopters equipped with sea-snorkels (allowing the helicopter to maintain forward speed when filling) and buckets on long lines (greater than 100 feet) the use of sea water does not create these maintenance issues. All Type 1 (large) helicopters contracted for firefighting in Australia have this equipment as standard and routinely use salt water. There may also be situations where the Air Attack Supervisor is conscious of the possible environmental effect of a large amount of salt water (for example on sensitive vegetation or in domestic water supply areas) and may require the pilot to use fresh water if available. This would only be the case in very limited circumstances. Again, in an emergency any suitable water supply will be used.