"We catch a lot of bugs at our altitude," said pilot Jason Robinson, pointing to the insect-spattered leading edges of the wings of the huge flying boat. The craft, one of three that gained fame dropping water on the huge Rhea wildfires this week, has been based at the old Clinton-Sherman air base at the Oklahoma Space Port at Burns Flat.

The plane, one of only four in the U.S., is a Bombardier CL-415, specially built for fighting fires, and flown by hand-picked pilots from the Aeroflite company based in Spokane, Washington.

The emergency has seen the three planes log 52 hours in five days, each dropping its massive load of 1,621 gallons of water every 10-12 minutes, or 15 to 18 times per fuel cycle, said Robinson, head pilot of the program.

The planes are being based at the Spaceport because of the uniquely long runway, the ample ramp space, and the gigantic hangars which can accommodate the tall planes.

"It's been very easy for us here," said Robinson, "There are very few hangars we can fit in."

He said they feel lucky to have use of the base, which is short flying time to the fires.

The quick flights to the wildfires in Dewey County have included a stop at Foss Lake to fill up with water; but mostly they have used Canton Lake further north.

At least one of those water drops saved a home from certain destruction. Robinson said they got an urgent call from the ground, saying there was not much time to save the house, so they diverted from their planned run and dropped their wall of water in time to save the house.

"Without these planes, this would have been a catastrophe of unmeasurable significance," said Bill Khourie, director of the Oklahoma Space Industry Development Authority, which runs the base.

The $35 million planes are relatively-recently built. The flying boats pick up their 1,621 gallons in about ten seconds by skimming the surface of a lake, ingesting the water through a special funnel that's not much bigger than a human hand.

The aircraft fly to the fire at about 1,000 feet above the ground and are guided to their target zones by a spotter plane, or Air Tactical Group Supervisor, flying at about 2,500 feet. The spotter communicates by radio with other firefighters on the ground. The pilots, however, are trained to make decisions about where to drop the water on their own.

Sometimes the target is unburned ground just downwind of the flames, often along a fire break carved by bulldozers. The plane has an infrared camera looking forward that helps them see hot spots even before flames are visible.

Getting the water right on target is an art learned by much practice, especially when there's a wind of 30 to 50 mph coming from the side, tail or head. The cross wind is the biggest challenge. There's no bomb sight; the pilot just has to have a feel for when to pull the trigger, said pilot Scott Miller. Ground and air observers are quick to call in a correction if needed, Miller added.

The intense heat from the flames causes convection air currents, which also carry smoke and debris. The pilots try to avoid those, but the planes have a special inertial separator to help protect the twin 2,300-shaft horsepower turbine engines from damage from birds and debris.

The heat also causes changes in air density, which can cause engines to surge or lose power sometimes.

Robinson said the water drop hits an area from 65 to 90 feet wide and about 350 feet long, although the high wind can stretch it out to about 500 feet.

The planes are designed to maneuver at slow speeds and have strongly-reinforced wings to take the heavy load of lifting off with the water. Being a true flying boat, each is equipped with life rafts, life jackets, mooring lines, and an anchor.

Bob Fisher

The close-up shows the small vent the plane uses to scoop up 1,621 gallons of lake water in about 12 seconds.

The U.S. Forest Service contracts for the flight service. The company charges a straight fee plus flight time and incidental expenses: some of the latter are paid for by the state. In large fire damage incidents, FEMA also participates in picking up the tab.