When Fire Attacks, DC-10 Tankers Storm to the Rescue

“Here they come.”

The firefighters look up to see an orange-and-white jet approaching the flaming hillside. A cloud of red drops from the belly—it is Phos-Chek, a fire retardant designed to keep the tinder-dry hills from burning.

In the summer months, this image replays again and again. More than 150 times so far in 2021, the aircraft providing this air support belonged to 10 Tanker, based in Albuquerque, New Mexico. The aerial firefighting organization flies a special modified McDonnell Douglas DC-10.

The DC-10 is the latest generation of large aircraft used for fire attack. The first so-called fire bombers were surplus military aircraft, often World War II bombers repurposed for peace time. These behemoths were modified to carry water and chemical flame retardant. Gradually, the WWII aircraft were replaced with later models, which in turn were used for decades. In 2002, after two fatal crashes—one of which was caught on videotape—the former military aircraft were grounded, and firefighters looked for new means to deliver air support.

Enter 10 Tanker. The company was founded in 2006. Robert Burrus, director of operations for 10 Tanker, said it was the first company to utilize turbine-powered aircraft to fight fires.

“The DC-10 is modified with an up-to-11,600-gallon gravity feed tank system and the center gear removed,” he said.

In the United States, fire season usually runs from spring to fall, but that doesn’t mean the tanker crews have much downtime, as the tankers travel around the world.

“During the normal season of April through October, 10 Tanker is contracted in North America through the United States National Interagency Coordination Center via the United States Forestry Service, or individual states like California.” Burrus explained. “In the opposite months of the North American fire season, we are contracted by other Southern Hemisphere countries like Australia’s national agency or individual states like New South Wales. We’ve also been contracted to work fires in Mexico and for Chile’s CONAF (National Forest Corporation) in the last couple of years.”

The DC-10 is crewed by two pilots and a flight engineer. When the tanker is relocating to a new temporary base, they often carry up to two mechanics. The aircraft have three main tanks that can hold either water or Phos-Chek.

“The tanks are currently certified for a total of 9,400 gallons at up to coverage level eight, which is eight gallons for every 100 square feet,” Burrus said. “The three main tanks—1, 2, and 3—hold 2,700, 4,000, and 2,700 gallons, respectively.”

In 2018, 10 Tanker upgraded the delivery computer on all of its air tankers to provide a gang drop, all of them at the same time, or a “sequenced”' drop, where one overlaps into the next. Each drop is dialed in based on the coverage level and drop requirements.

The tanks also have the capability to “split” drop, meaning they can drop part of the load on one section of the fire and then drop another line on another part of the fire.

The tankers average an hour of flight time per mission.

“Reloading usually takes 15 to 20 minutes and then they are back out to the run. But I have also seen it where the fire was right next to the airport and our tanker could set up for the drop right after takeoff and return in less than 20 minutes,” Burrus said.

The average duty day for the pilots is nine hours, but that can be extended up to 14 hours, depending on need. During the fire season, support staff are normally on a 20 days on, 10 days off schedule with a duty day of eight hours that can be extended up to 16 hours if needed.

Thanks to their aircraft’s ability to carry three times more payload to an event than other large air tankers, the crews essentially do three times the work at the same cost, which equates to an efficient and cost-effective operation for the federal taxpayers who pay for these services.

When a fire event happens, a temporary flight restriction (TFR) is created over the fire area to keep civilian traffic out of the way of firefighting efforts. When the TFR appears, the only flying in the area is supposed to be that of authorized aircraft, be it the tankers, helicopters or, in some instances, unmanned aerial systems—also known as drones. Radios are used to help keep the pilots aware of each other’s presence and all operations have a single coordinator.

“The wildland firefighters on the ground request air resources and that gets relayed to the air tactical group supervisor, which is flying overhead at approximately 5,000 to 6,000 feet,” Burrus said. “A dispatch is sent out to the coordination center, and the tankers are notified via the tanker base. From initial notification, the tanker has 30 minutes to get airborne.

“When the tanker arrives on scene, a lead plane directs the tanker to where the ground forces need the payload with a ‘show me,’ or talking them onto the line. The lead plane then leads the tanker to the line and pops smoke at the beginning of the line and end of the line. The tanker is usually only at the fire for five to 15 minutes, depending on if the pilots are familiar with the situation, and then back to the tanker base for more retardant.”

Training for the tanker pilots is conducted annually prior to the North American fire season. The training consists of classroom and simulator instruction and is led by the most experienced and tempered captains.

The tanker pilot applicants come from a variety of aviation disciplines.

“Some come from the fire community and they understand the fire traffic area in depth,” Burrus said. “Others come from a military background where they are able to pick up the subtle differences of a war zone tactical environment and the choreographed sequence of events associated with the fire environment.

“The attrition for pilots is very low, because we think it’s the best job on the face of the planet.”

It is imperative that the pilots can read the terrain during an attack run. Too low and there is the risk of collision. Too high, and the drop won’t be effective

“We don’t go below 250 feet AGL, and an effective altitude is preferred on every drop,” Burrus said. “For example, when we are asked to drop a very light coverage level on a flat piece of land, we need to be a little lower to prevent the retardant from blowing off the line. When we are asked to drop a high coverage level in a well forested area, the tanker sets up so that the heavy retardant is able to lose its forward momentum and drop through the trees without shadowing them, which is when only half of the tree is covered.”

A team of approximately four people accompany the tankers to the bases, driving trucks that contain spare parts such as tires, brakes, and anything else that is necessary to keep the tankers in the air.

Very often, the mechanics who support tankers come from the airlines because they need to have experience working on heavy aircraft. A few of them are recruited directly from the Airframe and Powerplant technician program at Central New Mexico Community College (CNM).

“We have a program where the students can work part-time in the materials department,” Burrus said. “There, they get a better familiarity with the industry vocabulary and flow of how everything works. When they graduate from CNM with an A&P, if a position is open, they can continue to work full time in the field under the supervision of an aircraft lead.”