• Flight Today

The Big Gulp

The world’s largest seaplane fights wildfires in California.

• By Tom LeCompte
• airspacemag.com, July 30, 2008

Long before you see it, you can hear it. With four 18-cylinder Wright Cyclone engines roaring at full throttle, the giant airplane sounds like a gang of Harleys bearing down on you. A huge rooster tail of water trailing behind it, the aircraft struggles to gain takeoff speed. Skimming along the lake, it covers a mile, two miles, three miles, before finally, almost imperceptibly, lifting off. Then, gently, it turns and heads toward a towering plume of smoke in the distance.

A 60-year-old Martin Mars has been dispatched to California this summer to help combat wildfires that have already burned more than a million acres. Most of the aerial firefighting is done by helicopters, but when it comes to dumping a lot of water fast, it’s hard to beat the Mars.

The British Columbia-based airplane is one of two in existence, both of which have been converted into firefighting water bombers. When the Mars Hawaii landed at Lake Shasta in northern California late last month, a crowd of 1,000 gathered to see the flying relic in action. Equally happy to see it were weary firefighters, who welcome the airplane’s ability to drop 7,200 gallons of water at a time, enough to cover four acres of burning forest. Even President Bush couldn’t resist getting a look at the behemoth during a recent tour of fire damage in the state.

When it was first rolled out in 1941, the Martin Mars dwarfed every other aircraft in the U.S. fleet. Four stories high, 120 feet long, and with a wingspan of 200 feet, the seaplane was conceived as a “flying dreadnought” for the Navy to use in long-range ocean patrol. But by the time it came off the production line in 1945, the service realized the airplane would be a sitting duck for enemy fighters or anti-aircraft weapons. So it was used to haul troops and cargo inside its double-decked hull. The initial order was for 20. At the end of the war, the Navy again changed its mind, reducing the number to six.

Except for the brief 30 seconds in 1947 when Howard Hughes’ ill-fated H-4 Hercules, or “Spruce Goose,” was airborne, the Martin Mars was, and still is, the largest flying boat in the world. Of the original six, one crashed, one was destroyed in an engine fire, and the remaining four were put up for auction by the Navy in 1959. A consortium of Canadian lumber companies decided to use them for firefighting, fitting them with water tanks and scooping systems.

Early in the program, two of the four aircraft were lost. Marianas Mars crashed in 1961 during a drop run that took the lives of all four crew members. Caroline Mars was damaged beyond repair during a storm in 1962. The two remaining airplanes, Hawaii Mars and Philippine Mars, have operated without serious incident.

Their current owner is the Coulson Group, a British Columbia-based consortium of forestry, manufacturing, and aviation companies. CEO Wayne Coulson had seen what the planes could do when he was working fires in the family’s logging business. “They’re just an incredible tool,” he says. “We knew the impact they could make.” Airworthiness wasn’t a concern. “We did a little calculation and found out that over 900,000 man-hours of labor were tallied up over 48 years per airframe,” Coulson says. “Each plane has been rebuilt several times over.”

The flying tankers are based at Sproat Lake, near Port Alberni on Vancouver Island. Coulson’s mobile support infrastructure includes a trailer truck outfitted with a communications center and a tool shop with a spare engine and parts. There’s also a fuel tanker (the plane’s four 2,500-horsepower Wright-Cyclone R3350 engines, which turn 15-foot propellers, guzzle nearly 800 gallons per hour) and a truck to haul service boats along with fire suppressant gel and foam. A turbine-powered Cessna 206 on floats also travels with the Mars, acting as a spotter to help lead the Mars to the drop. The entourage of pilots, flight engineers, mechanics, truck drivers, and support staff numbers 17.

In contrast to most firefighting aircraft, which drop retardant ahead of the fire to slow its advance, the Mars bombers operate on a gallons-per-hour concept, Coulson says: dropping the largest amount of water or suppressant gel directly on the blaze in the shortest possible time. Depending on the proximity of a fire to a lake large enough to accommodate the Mars (one with at least three miles of clear area to allow for the approach, scooping, and climb out), the Mars can drop 7,200 gallons of water on a fire every seven minutes for six hours.

Recently, Coulson says, a review of air operations out of the Redding fire air base revealed that the Grumman S-2 Tracker and P-3 Orion operating from there dropped a total of just over 80,000 gallons in a day. In contrast, Hawaii Mars alone dropped more than 100,000 gallons.

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.

Eventually, the airplanes will become museum pieces, Coulson concedes. But until then, they have a lot of fires still to fight.