Tuesday, September 30, 2008
The 109th Airlift Wing pilots the world’s largest ski plane to the Greenland ice cap
Overcast skies create challenging near-whiteout conditions.
Touching down on the 15,000-foot skiway is bumpy and noisy, but with propeller pitch set to reverse, it doesn't take much distance to stop. "As a general rule of thumb," Falvo tells me, "2,000 feet is enough distance to bring the aircraft from near takeoff speed down to taxi speed. As airspeed decreases, the friction between the skis and the snow increases, since any lift the wings were generating goes to zero, and the weight is transferred to the skis. It feels similar to flying a single-engine airplane on a soft field."
I step out of the Hercules and enter a cold, surreal landscape whose endless whiteness is punctuated by bright-yellow tents, piles of cargo and scientists traversing their workspace on skis. The horizon remains elusive and there's a quietness disturbed only by the crunch of ice underneath boots. During our time on the ground, the aircraft's four engines remain running, to the tune of 2,800 pounds of fuel per hour. "If engines get too cool, the oil begins to thicken," explains Maj. Bradley. "Every time you stop and start an engine, there's another chance that something may not let the engine start again. If you can keep 'em running, keep 'em running."
Rocket bottles are attached to the fuselage for additional takeoff power.
Getting our ski bird off the snow isn't an easy task, and our first two takeoff "slides" are aborted. "Much of what we do is a matter of technique, not always procedure," says Maj. Falvo. "Sixty-five knots is in the ballpark of when it's possible to lift the nose and have enough elevator authority to keep it off the snow, but much of this depends on snow conditions, center of gravity, flap setting and fuel quantity, so it isn't really an exact airspeed every time." Pilots will try different flap settings, rearrange cargo or leave equipment on the ice. On open snow, a takeoff slide can extend as far as 20 miles! When necessary, the crew will employ assisted take-off (ATO—not JATO, which implies the use of a jet engine). Eight rocket bottles attached to the fuselage will provide the same power as an additional engine for just 15 seconds, so timing is critical.
Page 3 of 4