Mars Attacks

Aviation International News » June 2004
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October 4, 2007, 10:01 AM

“We need the Mars! Get the Mars!” shouts a frantic firefighter over the VHF fire frequency. A wildfire is racing up a hillside on the eastern fringe of Osoyoos, B.C., Canada, and seems certain to engulf a house in its path. Helicopters are bucketing water onto the flames in an effort to slow the fire’s advance, but still the flames leap up the side of the valley unimpeded. Recognizing the urgency of the situation, the fire boss circling overhead in a Commander 690 bird dog calls in the Martin Mars water bomber to save the dwelling from destruction.

Through a veil of grey smoke and cinders, captain Peter Killin begins weaving the 162,000-pound red and white Mars flying boat through the Okanagan Valley towards the blaze.

“Which house?” calls Killin.

“Your target is the white house!” yells the firefighter on the ground.

Killin sees it: an upscale home directly in the path of an onrushing inferno. Already, advancing tendrils of flame are curling around the home’s supports as the two homeowners (who refused to leave when ordered to evacuate) throw buckets of water from the balcony above.

Manhandling the Mars through the turbulence of convective air currents swirling up from the fire below, Killin slows the enormous flying boat to 120 knots and lines up for a downhill run at 150 feet above ground. Passing almost directly over the house, Killin depresses the load release switch on the control wheel, unleashing a 7,200-gallon wall of water and fire retardant directly in the path of the blaze. The home and its owners are saved…for now.

Without question, Killin’s accurate drop averted certain disaster. But like many captains who fly the Martin Mars, he gives much of the credit to the airplane. Flying the water bomber, he says, “is like tossing horseshoes or hand grenades–close is good enough.”

True, perhaps, but Killin’s modesty isn’t convincing. What he doesn’t mention is that, like all other pilots and engineers on the Mars, he is one of the rare few who have the necessary experience, skill and dedication to work for Flying Tankers, the company that operates the only two Martin Mars flying boats in existence.

“There’s not a better initial attack aircraft in the world,” said Roy Copeland, director of maintenance for Flying Tankers. “There’s nothing with the same capability and loads; the airplane is so effective that controlling one fire pays for the aircraft.”

However, as with most firefighting jobs there’s a lot of sitting and waiting for the alarm to ring. On average, Flying Tankers doesn’t log much more than 100 hours a season on each airframe, and much of that is accumulated on training and maintenance flights. In recent years, most work for the Mars has been close to home in Western Canada, particularly with the B.C. Forest Service, but the company has also operated in Alberta, Washington state and California on occasion.

Terry Dixon, general manager of Flying Tankers, said the company has explored a number of potential overseas contracts, and is prepared to take on new work in eastern Canada and the U.S. as well. However, he notes, “Our first priority is to TimberWest and the province of British Columbia.”

Over four decades, the combined firefighting capability of the two Mars has proved invaluable to forestry companies and the province alike. Nevertheless, as a result of challenges facing the logging industry in recent years, the future of Flying Tankers has not been certain. How much longer they will continue to operate depends largely on the financial viability of Flying Tankers.

“The bottom line is you have to make a buck,” says Copeland. Accordingly, TimberWest has reviewed the Mars program annually, and until recently the outlook has been questionable.

But what a difference a province-wide inferno can make. Last summer, Flying Tankers had its busiest season on record, logging 293 hours fighting 66 different fires throughout B.C. Not only did the two Mars water bombers pay for themselves, but they showed an encouraging profit for the company. A TimberWest spokesman told AIN, “There are no immediate plans for putting the Mars out of service.

TimberWest has a huge investment in forestlands on Vancouver Island, and protecting that from fire is important.” But, he added, “Contract work is going to be important to keeping the program operational.”

Mars Mania

Flying Tankers gets a lot of visitors to its tanker base on Sproat Lake. Indeed, the airplanes attract interest from hundreds of tourists and airplane enthusiasts from all over the world.

One visitor, an ailing American veteran who wanted to see the Mars before he died, was particularly memorable. The man and his wife had driven to Sproat Lake to see the aircraft, but unfortunately both airplanes had been dispatched to fight a fire in the B.C. Interior, near Osoyoos. Undeterred, he and his wife got back into their car and drove to see the airplanes there.

When the old soldier arrived, he introduced himself to the crew and told them his story. It turned out he had been serving in Korea with the U.S. Army when he was badly wounded. So serious were his injuries that he was flown back to the U.S. for treatment in a Martin Mars.

Late in life, when the man discovered this very airplane, the Philippine Mars, was still flying, he decided to make a final pilgrimage to see it.

Touched by the man’s connection to the aircraft, the Flying Tankers crew took him out by boat for a tour of his old ship. Remarkably, once the fellow got aboard he remembered exactly where his stretcher had been placed, and he found the small porthole window his pillow had been next to. He said the last thing he remembered before losing consciousness on the long flight home was looking out that window at the ocean below. He credited the Mars with saving his life.

Flying Operations

During fire season, the two Mars are kept in a state of readiness in accordance with whatever fire hazard conditions exist. When on high or extreme alert, crews crank up the engines at regular intervals to keep them warm at all times. (In cold weather it can take 30 to 40 minutes to get the engines up to takeoff temperature.)

When a Mars fires up its four 2,500-hp Wright Cyclone R3350-24WA radials, the sound of 72 cylinders thundering in unison sounds more like a biker’s funeral procession than an aircraft warming up.

If you are a bush pilot, this is as cool as it gets. “As soon as I hear those engines, I think what a lucky bastard I am,” said captain Steve Stackhouse. “And it’s a super-stable airplane to fly–like a big Cessna 172. Everything happens slowly and it’s easy to fly, but very heavy on the controls.

“The elevators and rudder are hydraulically boosted, but not the ailerons, so flying in the valleys is hard: it’s like taking an 18-wheeler into a small parking lot. By the end of a long day you’re tired.”

On the water, Stackhouse said, the Mars can be a bigger handful. “It’s really tough on the water. You have no brakes, of course, and it tends to fishtail. We generally use the number one and four engines to steer; using number two and three is harder. The most challenging part of the job on the water, though, is trying to hook on to the mooring buoy. It can be pretty entertaining to watch sometimes.”

For such an enormous machine, it is surprising to learn that the Mars is actually certified as a single-pilot aircraft. The captain does most of the flying on a fire, with the flight engineer running the power and the first officer setting the flaps and operating the water systems.

A typical pickup requires about three miles of clearance: one mile for the approach; one mile for the pickup; and one mile for the climb-out. Generally, the captain executes a normal approach and landing, touching down at around 98 knots. At this point he keeps the aircraft on the step while allowing the airspeed to decrease to 70 knots. The captain then passes engine power to the flight engineer, who simultaneously extends the belly probes to the down position. The ram pressure for injecting the water into the tanks is such that the aircraft takes on water at a rate of more than a ton per second. To compensate for this added weight, the flight engineer continues advancing the throttles to maintain a skimming speed of 60 to 70 knots, thus ensuring the aircraft remains on the step. Pickup time averages 25 seconds.

When the tanks are full, the captain calls for the scoops to be raised and for takeoff power to be applied. Once the aircraft is airborne, foam concentrate is injected into the water load (normally 30 gallons of concentrate into the 7,200-gallon water load), where it disperses and remains inert until the load is dropped. The tumbling action of release expands the mixture and converts the water load into a foam load, increasing the load’s efficiency up to 50 percent.

When working in close proximity to a fire, this sequence might be repeated as frequently as every 15 minutes per aircraft. Working in tandem on a fire, that works out to a 7,200-gallon drop on a fire every seven minutes, with each drop dowsing up to four acres.

Maintaining the Mars

“The Mars is built like a tank,” said Copeland. Nevertheless, he concedes that keeping the Mars operational is not without its challenges. Despite its relatively simple design, the nearly 60-year-old Mars is a labor-intensive airplane.

“We do a lot of preventative maintenance,” said Copeland. “Every year there are major overhaul projects. Fortunately, we’ve got tons of spares, and all the manufacturer’s drawings so we can repair a lot of our own parts.”

In the winter months most of the pilots take off their flight suits and don coveralls to work alongside the full-time maintenance technicians. At the end of every fire season the Mars are hauled out of the water for intensive preventative maintenance and repairs. The most recent project undertaken by Flying Tankers was a complete overhaul of Hawaii Mars to mint condition. Copeland said next year’s winter project is to do the same for Philippine Mars.

Summer maintenance, conversely, is operational. During the fire season, almost all maintenance and repairs on the Mars are carried out on the water, which can be daunting, depending on the task at hand.

“On shore they’re easy to work on,” said aircraft maintenance engineer Mike Johnson. “Out on the water it’s more time-consuming. We’ve changed props on the water, but it requires boats and rafts, or beaching the airplane.”

Perhaps the trickiest aspect to working on the Mars is servicing the aircraft’s engines. These two-row, supercharged, air-cooled radials jut out from the leading edge of the wing, and are many feet higher over the water than you’d want to fall from.

But the technicians at Flying Tankers are resourceful and have devised a number of ingenious solutions to each problem. The first is a floating workshop raft that the technicians tow out and secure to the hull of either flying boat. Further, small individual sea-stand platforms have been rigged to fit onto the engine mounts, thus allowing mechanics to work in relative ease without the floating raft. (Access to the rear face of the engines is also possible via a passageway inside the wings.)

Another challenge on the water is fueling, but Flying Tankers has a solution for that, too. With both Mars moored several hundred meters from shore, a fuel line has been run out to the aircraft.

While the tanker base is uniquely adapted to servicing the two flying boats, working away from home is not especially difficult for crews. Equipped with special fly-away kits, the Mars can dispatch to any location worldwide and remain relatively self-sufficient.

After working on the water for 40-plus years, Flying Tankers crews are prepared for the inevitable, as well as the bizarre. Through experience they have learned to do everything from illuminating the airplanes with night lights to deter drunken boaters to carrying concrete highway dividers on board for use as makeshift mooring anchors when the airplanes dispatch away from base.

It’s Not about Size

If there is one striking thing above all about the Martin Mars water bombers, it is their sheer enormity. Everything about them is big. They are big airplanes, flying big loads, in big mountains. But what makes these airplanes truly special is not their mammoth size, but the crews who continue to give the Mars a lease on life in a job for which it was never originally intended, 60 years after its development. Truly, the unique collection of career bush pilots and maintenance technicians who earn their livelihood operating the aircraft are unusually dedicated people. Most have made personal sacrifices to work for Flying Tankers, and each year they continue to do so, despite an uncertain future.

For now, at least, it appears the two Mars have several more operational years ahead
of them preserving forests and saving lives and homes.   

Bigger Help Is on the Way

Go big, or go home. That seems to be the inspiration behind Evergreen Air Center’s ambitious program to modify a Boeing 747-200 (N470) for aerial fire-suppression applications. Aptly designated the Supertanker, the former Evergreen cargo aircraft is equipped with a 24,000-gallon internal tank capable of delivering 216,000 pounds of fire retardant.

Evergreen hopes to obtain certification for the airplane by July 4. The company has not yet released results from the water drop testing done between March 21 and April 24 at the Evergreen Air Center in Marana, Ariz., but a spokesman said the flight-test aircraft made more than 50 flights and 82 drops, carrying a total of 536,000 gallons (4.5 million pounds) of retardant. During testing, the Supertanker operated VFR, making drops at altitudes from 10,000 feet msl down to 300 feet agl, though the majority of tests were conducted at between 400 and 800 feet agl.
Equipped with a patented, internal pressurized drop system, which can be loaded by palette, the Supertanker disperses retardant under high pressure, thus causing negligible g-loading during a drop. It can also drop its entire load in eight seconds, or in several segmented drops.

Operating within its original design envelope, the Supertanker’s drop speed is 140 knots, configured with 30 degrees of flap, which provides a 30-percent cushion above the airplane’s stall speed.

Is a 747 modified for aerial fire suppression a bit much, though? Not so, says Penn Stohr, manager of Supertanker operations for Evergreen. “We evaluated other aircraft but found them unsuitable. In the jet category the 747 proved most suitable for two reasons: it is a good aircraft at low speeds; and it has greater margins in performance.” Stohr added, “And tactically it is ideal because you don’t have to make so many trips.” Indeed, the Supertanker can carry in one load what would take the combined effort of several other firefighting aircraft to deliver. What’s more, at Mach 0.86 the Supertanker can travel the distance to the fire in a fraction of the time.

But what about maneuvering an enormous jet aircraft at low level in mountainous terrain? Stohr said, “We knew full well it would have terrain limitations; it is not an ideal aircraft down low in a canyon. But the typical air tanker drops at a height of about 150 feet agl, whereas the Supertanker can drop at 400 to 800 feet agl without too much dispersion.”

So far, Evergreen’s aeronautical engineers have spent more than 20,000 hours developing the Supertanker. They consulted with Boeing at the outset of the program, and Stohr says the manufacturer supports the capabilities of the 747 to perform aerial application. But he makes it clear that “the Supertanker is purely an Evergreen investment. It was not encouraged or discouraged by any government agency. This is our own independent program.”

The impetus behind Evergreen’s Supertanker is an attempt to update the air tanker fleet in the U.S., which consists mostly of older surplus military aircraft, some of which are World War II vintage. Because the Supertanker is newer, and operated under Part 121, with a certified maintenance program (and compliance with all Airworthiness Directives), Evergreen is promoting the Supertanker as a timely alternative capable of satisfying the capacity recently lost when the USDA Forest Service grounded 33 aging air tankers.

Evergreen said it plans to market Supertanker fire suppression both domestically and abroad, with potential clients ranging from federal and state governments, as well as the U.S. Forest Service and the Department of the Interior, to various overseas markets. The spokesman said, “The Supertanker has advantages in safety and effectiveness, with better payload, drop speed, engine performance and manufacturer support than any other large aircraft.”

While there are no firm orders yet, Evergreen said “a number of government agencies have expressed an interest in learning more about the biochem capabilities of the aircraft and refining the drop system for this mission.” For now, Evergreen intends to modify three or four 747s for service with the Supertanker fleet.

Evergreen’s experience in aerial firefighting dates back to 1960, when it formed Evergreen Helicopters, which today operates 25 helicopters annually on aerial firefighting duties. It got into fixed-wing tanker operations when it purchased Johnson Flying Service of Missoula, Mont., in 1975.   

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