Technology has aided forestry for years, especially when performing prescribed burning to keep fuels on forest floors from building up to dangerous levels. Now, the U.S. Forest Service (USFS) is using technology of unmanned aircraft in hopes to save lives during those operations.
A USFS firefighter was killed in a helicopter crash while working a prescribed fire operation in Sam Houston National Forest three years ago in Texas. The pilot hired to fly the aircraft and a second USFS employee were seriously injured but survived the crash.
Just shy of the third anniversary of the death of the firefighter, USFS sent a crew to the Kisatchie National Forest’s Calcasieu District to demonstrate how drones are being used to ignite prescribed burn operations in Louisiana.
Drone usage is relatively new to the USFS, said Steven Staples, fire management officer for the Calcasieu District of Kisatchie National Forest, and it’s very new for Kistachie.
“We can burn up to 1,500 acres at a time,” Staples said, though most prescribed burns using drones are in the hundreds of acres, such as that day’s plan to burn 556 acres.
Safety is a big factor in using drone technology, Staples said. In the event of a drone crash, the risk to life is extremely low — as long as the drone doesn’t fall on top of someone. There’s no combustible fuel, so no exhaust. So, the process’s carbon footprint is much lower.
There are some similarities, through. When a helicopter is used to ignite the prescribed fires, a pilot is needed to fly the aircraft, the pilot must file a flight plan prior to the operation and ping-pong-sized plastic balls are dropped by machine, known as the plastic sphere dispenser, or PSD.
Using a drone, a licensed pilot must operate the drone, as per Federal Aviation Administration rules. The drone pilot is required to file an aviation plan prior to the operation. In this particular prescribed burn, the plan had to be coordinated with the military because of the close proximity of Fort Polk. The mechanism that is used to drop the plastic balls, called the IGNIS machine, is similar also, although the spheres are almost half the size of what is used in the regular machine. The remote for the drone also is used to operate the IGNIS machine.
Jacob Henrie is the pilot who operated the drone at the March demonstration. As he meticulously cleaned the device attached to the IGNIS machine that releases the spheres, he described the use of drones as a risk transfer. It takes at least three people to perform the ball drop from a helicopter: a pilot, who is usually contracted by the USFS, and two forest service employees. The drone has need of a pilot and observers, but none of whom are in the air.
The IGNIS machine, is well cared for because, as is the case for anything mechanical, problems can occur.
The plastic spheres contain a powdery substance and the mechanism has to inject a liquid chemical. The chemical reaction ignites the sphere, depending on the amount of the liquid, up to 30 seconds after injection.
“If the ball doesn’t eject properly, it hangs away from the hopper and is allowed to burn out,” Henrie said. “Then we bring (the drone) back to fix it.”
The drone has cameras that can show the pilot the terrain the aircraft is flying over. Observers also can watch on a television monitor that is connected to the drone’s cameras. They can see what the pilot sees.
It also has capabilities to view hot spots by its infrared features.
Cost is another consideration, said Nate Dewhurst, a USFS employee from North Carolina. It costs about $50,000 for a complete setup for a drone and it can be used multiple times. Leasing a helicopters with its pilot alone can cost $16,000 a day, according to a 2020 article by Fire Ignition Management.
Planning is essential, the pilot said, as considerations for the weather, the typography and fuels on the forest floor will help determine where the spheres are released and the frequency of their release.
Weather, said Staples, is likely the biggest factor while considering when to burn.
“Everything has to be right,” he said.
Staples said anyone wanting to find out where the USFS is burning can check out the agency’s Facebook page. Search for U.S. Forest Service - Kisatchie National Forest.