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(Coulson Aircrane Ltd)

The Big Gulp

The world’s largest seaplane fights wildfires in California.

airspacemag.com

(Continued from page 1)

The state of California also operates a DC-10 tanker that can unload as much 12,000 gallons of retardant per drop, nearly two-thirds more than the Mars. But the DC-10 requires a wide swath of airspace, making it tricky to integrate with other aircraft.

Each Mars carries 600 gallons of foam concentrate, which, when mixed with water, creates a heavier covering to penetrate dense tree cover. Thermo-Gel, a longer-lasting fire suppressant, can be used to protect structures. To switch from straight water to foam or gel, the pilot merely pushes a switch to begin the mixing process.

Even with the water tanks, there’s room to spare inside the Mars. The interior is as big as a 15-room house, and the flight deck could be a studio apartment. Flying the Mars requires a crew of four: a pilot, a first officer, and two flight engineers, who sit at a small station behind the cockpit.

So what’s it like to fly?

“Oh, it’s a pussycat,” says John DeBourcier, 66, who has been flying the Mars since 1977. “As you get into bigger airplanes you learn to anticipate more. In the Mars, you have that long, high-lift wing, and with those little ailerons it just doesn’t want to move, so going from a 30-degree right bank to a 30-degree left bank is a big turn.”

Because much of the flying is done at low altitude in often rugged terrain, as well as on public lakes where the obstacles range from boaters (who sometimes film the action) to exposed rocks or floating debris, “your eyes have to be on what’s in front of you,” says DeBourcier.

The most demanding operation in terms of teamwork and precision is a water pickup. First the pilot sets up for what would otherwise be a normal lake landing. After making contact with the water, DeBourcier hands control of the throttles to the engineer, who tries to keep the airplane at 80 mph. The pilot then lowers the probes, two forward-facing straws that draw in water, and turns on the switch releasing the foam or gel to be mixed with the water. When the probes are lowered, DeBourcier says, the Mars pitches forward and generally slows down a bit, especially if it’s hot or the lake is at a high altitude. The probes draw in water at a rate of about 270 gallons per second, so it takes about 30 seconds to pick up a load of 7,200 gallons. As the tank fills, the pilot can feel the aircraft getting heavier. “You’re becoming more boat than airplane,” says DeBourcier.

For the drop, depending on the conditions and the type of unloading required, the pilot will fly from 300 feet down to 50 feet above the trees. The pilot pushes a release button on the control yoke, and a series of 22 doors on the underside open to release the water, which can be released all at once, or half on one run and half on a second.

When the water is released, the sudden changes in weight and center of gravity cause the Mars to pitch up. “If you don’t want it to pitch up, you have to push the control stick just about to the panel,” DeBourcier says. The most important thing is to drop the water in the right spot. To do this, he says, you allow for the plane’s speed and altitude, the wind, and—maybe—a little luck. Then it’s back to the lake for more water, every seven minutes, over and over again.

Coulson and DeBourcier enjoy the attention the Mars gets wherever they go. During recent stops in California at Lake Shasta and Lake San Antonio, many people came up to see the plane, talk to the pilots, or tell stories about how they or their dad or uncle or someone they knew was a pilot, an engineer, or a passenger aboard a Mars. One older man, recalls Coulson, came aboard the plane, pointed at a window, and recounted that he had stared out that window for 12 hours many years ago as a young man returning home after World War II.

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