Australian fleet poised and ready, while waiting for late arrivals

The Australian aerial firefighting fleet has been upgraded as an anticipated long, hot summer begins across the south, with most states expanding access to more aerial options in their local fleets.

Late season fires in the northern hemisphere have delayed the arrival of some the fleet. In Victoria, the announcement of the summer firefighting fleet of 54 aircraft was tempered by the statement that “2 Aircranes will also join the fleet once their service period ends in North America. Three additional aircraft will be on short-term contracts until the Aircranes arrive.”

Erickson Air-Cranes in Greece
Erickson Air-Cranes on northern hemisphere service, October 2021 in Greece. Photo by Dimitris Klagos.

The National Aerial Firefighting Centre (NAFC) has contracted 177 aircraft on behalf of Australian state and territory governments for the 2024-25 season. This fleet is supplemented by NAFC aircraft contracted as “call when needed”, and additional state owned and state contracted aircraft hired to meet peak demand across the country. In total more than 500 aircraft, provided by over 150 operators, are available as a shared resource for firefighting across Australia for season 2024-2025.

Amid regular calls at the political level for a national sovereign fleet that is less dependent on the variable end to the northern hemisphere fire season, NAFC figures show that 95 percent of the Australian firefighting fleet is already resident year-round in Australia, including 75 percent owned and operated by Australian companies.

The remaining 5 percent are predominantly the larger aircraft, both fixed wing and rotary, that follow the fire seasons around the globe. NAFC contracts these under partnerships between Australian and foreign companies. The aircraft fly on complementary contracts in the northern hemisphere and then are, ideally, packed up and returned in time for the Australian summer.

But that start of Australian summer has its own variable timing that contributes to the annual problem of overlapping seasons across the hemispheres: along the heavily populated east coast of the continent, bushfire season can begin as early as August into September, while New South Wales regularly has a highly active October and November. Further south, Victoria fires appear around December, with Tasmania seeing most activity from January onwards.

With the Australian fire season now well into its southward trajectory from the tropical north – currently in its Wet Season after an active Dry Season of bushfires – to a southern Australia with a year of below average rainfall, fire authorities are relying on their aerial resources for essential support to ground crews. The large grassland regions abutting the forests are particularly vulnerable this year, with several large outbreaks currently being dealt with in Victoria.

The Australian Government has funded NAFC with around $A100 million ($USD 63M) for this season and the next. Two Blackhawks and a Sikorsky S-61N have recently joined the fleet.

At the end of September 2024, the contracted national fleet comprises of:

  • 6 Large fixed wing air tankers
  • 16 Large rotary wing aircraft (Type 1)
  • 68 Medium and small rotary wing aircraft (Type 2 and 3)
  • 54 Fixed wing firebombers
  • 18 Light fixed wing

Coulson Aviation Australia has secured a long-term contract with Australia’s largest state-based fleet. The New South Wales Rural Fire Service announced in July this year that Coulson would manage the NSW fleet for the next 10 years, after managing it for the previous five.

The NSW RFS fleet of 11 aircraft includes a 737 large air tanker (the Marie Bashir, which has seen service in North America including a three-month stint in 2023), two Cessna Citations, six Bell-412 helicopters, a Chinook helicopter, and a Beechcraft Super King Air. Under the new contract, these aircraft will be overseen by primarily Australian crews, in a shift to bolster the local workforce and makes NSW more self-sufficient.

NSW RFS 737 fire tanker at NIFC.
The New South Wales Rural Fire Service 737 at the National Interagency Fire Centre in Boise, Idaho in 2023.

The fleet also supports other emergency services, such as the NSW State Emergency Service for rescues during floods, when they are not being used for firefighting duties.

Even the smaller states are increasing their capacities from the NAFC pool. Tasmania has received 15 dedicated aircraft from the NAFC fleet, to be managed locally by the Tasmania Fire Service. South Australia has retained its record high level of 31 aircraft from last year into this year, managed by the Country Fire Service, including five Blackhawk helicopters. Western Australia, immense in size but small in population, has found an extra $A10 million for its fleet, which includes four Blackhawks and a C130 Hercules.

Helping smokejumpers to predict wind turbulence

Wind turbulence is a well-known factor in the complex wildland fire environment.  Sometimes it is the wind shear over vegetation, buildings, or terrain, and other times it’s the buoyant forces from solar surface heating or thermal plume injections from the fire itself.

Smokejumpers approaching landing zone in 2011. Photo: Mike McMillan

For a smokejumper, parachuting from a low-flying aircraft in a remote and rugged landscape, turbulence near the ground at the atmospheric boundary layer (ABL) is of particular concern.

Scientists at the Rocky Mountain Research Station have published a study on how to better predict terrain-induced turbulence to assist smokejumper operations.

Smokejumpers are employed by the United States Department of Agriculture Forest Service and the Department of Interior Bureau of Land Management throughout the western US and Alaska. These smokejumpers use Ram-Air style parachutes, which require forward speed to maintain lift (USFS 2018). Small wind fluctuations can drastically impact parachute aerodynamics. Existing protocols to assess ABL turbulence during jump operations include the release of weighted streamers to visually assess the winds and turbulence. Numerous hard landings, serious accidents, and fatalities have been attributed to unexpected near-surface turbulence during training and operational jumps. Searching “Smokejumper Accident” on the Wildland Fire Lessons Learned Center’s website shows an average of four serious jump injuries per year between 2015–2023 in which turbulence potentially played a factor.

Wind flow over ridges can create large wake zones with increased turbulence that extend far downwind. This phenomenon likely contributed to the hard landing that resulted in a smokejumper fatality during a jump on the Eicks Fire in New Mexico in 2021 The research team used WindNinja, the high-resolution diagnostic wind model for wildland fire applications, to investigate surface winds and turbulence during the jump operation on the Eicks Fire. The findings indicate that the jump took place in the wake of a tall upwind ridge that created a large re-circulation zone with areas of turbulence.

WindNinja is routinely used by fire managers in the US and around the world and can drive operational fire spread models such as FlamMap and Prometheus. These uses take wind speed and direction predictions from WindNinja, however, the research notes that WindNinja can also generate information about the near-surface atmosphere, such as turbulence and shear. The researchers say these capabilities, to date, have not been made accessible to end users or formally assessed for accuracy by the development team. WindNinja has been evaluated in the field but not in the really rugged terrain where smokejumper operations often occur. Here, wind modeling is far more complex and challenging.

This study concluded that WindNinja’s lesser-known ability to simulate wind turbulence could be of use for assessing smokejumper operations under moderate to high wind conditions.

They also suggest that although this work focused on smoke jumping, real-time turbulence predictions from WindNinja could be useful for other near-surface firefighting aerial operations.

Predicting terrain-induced wind turbulence for smokejumper parachute operations is an open-access article in the International Journal of Wildland Fire.