For weeks, the world’s largest firefighting aircraft in the world lay in wait at a secluded airplane hangar outside Tucson.
The Global SuperTanker, a Boeing 747-400 series passenger jet converted for firefighting, was housed at Pinal Airpark while Ascent Aviation and Logistics Air conducted routine maintenance ahead of the unpredictable wildfire season ahead.
The plane, named for John Muir, the “Father of Our National Park System,” has been heralded as one of the ultimate weapons against wildfires. It can dump up to 19,200 gallons of water or retardant in just six seconds as low as 200 feet above ground level before climbing away.
Then, it takes only 13 minutes to refill the plane before returning to the sky. A typical tanker takes more than 30 minutes.
The SuperTanker has been used in dozens of wildfires across the world since 2009, but it proved indispensable in 2018 when Cal Fire enlisted the plane’s help with some of the most devastating wildfires in the state’s history, including the Carr Fire in Northern California and the Mendocino Complex Fire.
“It’s a force multiplier,” Global SuperTanker chief pilot Cliff Hale said. “When you need to build containment lines fast, having that very large capacity can really help the guys out on the ground.”
“There had to be a better way”
Hale watched footage on TV of a wildfire burning near his parents’ home in Albuquerque in 2000. Thousands of people were forced to evacuate as the blaze approached a town.
Hale was transfixed as the broadcast showed a dated airplane dump a load of retardant on the fire. The plane dumped a few thousand gallons, but it was over in seconds. There were no other tankers around and it would take hours for the plane to fill up before making another pass.
“I just thought, with all these people running for their lives, that there had to be a better way,” Hale recounted.
Hale, who was a captain on a 747 with Evergreen Airlines at the time, began developing the idea to turn a 747 into an air tanker. He pitched it two years later to the chairman of Evergreen, who immediately realized Hale was talking about creating a 747 fire bomb.
Hale was given the go-ahead shortly thereafter.
It would take years to get the first iteration of the SuperTanker in the air and even longer to get the necessary certifications. The converted 747 was first used in the U.S. in 2009 during the Railbelt Complex Fire in Alaska, which burned more than a half-million acres. The two drops were performed at no cost to the local forestry department in an effort to demonstrate what the aircraft could do.
“It was really the state giving it a shot,” Hall said. “We were finally getting the chance to prove it, and I think it’s proven to be quite successful.”
Typically, a lead plane will fly ahead of the 747 and signal when to drop and for how long. It’s usually used to create or maintain a perimeter around a fire, instead of a direct attack, to better support the crews on the ground.
One fire chief even refers to it as “The Big Hammer,” Hale noted.
“It really goes back to it’s just another tool in the toolbox,” Hale said. “It’s not a complete solution to everything, but it does definitely has its place.”
“World’s largest, fastest squirt gun”
Scott Olson, vice-president of maintenance for Global SuperTanker, was there when the current plane was pulled out of the desert four years ago.
The 747 first entered service in 1991 as a passenger plane for Japan Airlines. Evergreen Airlines leased it and converted it to a freighter for a year. Practically everything was stripped out of the plane and floor beams were added to strengthen the structure.
Then, Evergreen went bankrupt and its assets were spread throughout the country. The first iteration of the SuperTanker was destroyed for salvage.
Shortly after, Olson found a new plane that had also been owned by Evergreen to retrofit.
Very little had to be done to the overall structure of the plane to convert it from a freighter to a wildfire-fighting machine. Evergreen had already cut a cargo door in when they converted it from a passenger plane. Olson and his team added four outlets to the belly of the plane that could dump 9,200 gallons of liquid in 13.3 seconds. The existing sprayer tank system was put into the new plane.
Each of the 10 massive tanks was loaded one by one into the plane through the cargo door. The tanks can be loaded independently to allow for customized combinations of retardant or water based on the demands of the fire or the client. Each side of the tanks holds 9,600 gallons, for a total of 19,200 gallons.
The tank system can be configured for segmented drops, which allows the retardants to be released multiple times while in the air.
Most traditional air tankers simply dump liquid directly onto a fire. When designing the SuperTanker, Olson said he knew he had to build a system that would move all the liquid out of the plane no matter what.
This led them to a pressurized tank system Hale compares to the “world’s largest and fastest squirt gun.”
Spraying, as opposed to dumping, makes it feasible for the plane to spray retardant into areas it wouldn’t be able to safely maneuver in, like a valley, and the drop doesn’t damage cars or trees.
The system needed to be able to flex with the plane without breaking or leaking. Malleable Victaulic couplings were used to give the system the right flexibility, while still maintaining structural integrity.
“If the movements aren’t taken into account, there will be a failure somewhere,” explained Dave Hudson, an engineering fellow with Victaulic.
Unlike traditional air tankers, the SuperTanker can also land loaded. This allows the crew to fill up the plane in the U.S. before traveling to another country.
Using the SuperTanker in US
Breaking into the U.S. market has been challenging.
The SuperTanker fought fires in Israel in 2016 and was deployed in Chile in 2017. Its operator have secured contracts with Cal Fire, the Oregon Department of Forestry and Colorado.
It does not have a contract in Arizona.
The crew is constantly on call, ready to respond to a fire anywhere in the world within hours of receiving the alert.
But it took years to reach even this level of acceptance, Hale said. Many agencies were hesitant to accept it due to its large size and volume, making it difficult to secure government contracts.
“It’s been a slow snowball going down the hill ever since,” Hale said. “We keep getting more and more use and it’s proving itself the more we go.”
Some have attributed the U.S. Forest Service’s reluctance to widely use the plane to the high cost, which can run as much as $250,000 a day.
Others have pointed to outdated regulations and procedures that were designed to dictate traditional firefighting air tankers.
That came into play in 2017 when California’s fire agency couldn’t use the plane until it was approved by the Forest Service.
The approval came in time to be used on the massive Thomas Fire that ignited in Southern California in late 2017.
“Very experienced people decided to give it a look and they liked what they saw,” Hale said.
“They kept going and, as more people learned the capabilities, we found more ways it could be used and where it couldn’t be used.
“They found a place for it and it’s been very helpful.”