FREDERICKSBURG, VA. -- "Goggle up," came the radio command.

Five Virginia National Guard helicopters with their rotor blades spinning paused in a line on the grass runway at Fort A.P. Hill. Capt. G. Richard Hubbard of Powhatan would be leading the flight as the 76th Combat Aviation Company prepared to fly a night vision goggle mission.

This would be the first of several goggle flights carrying some of the 4,000 soldiers of the 29th Light Infantry Division taking part in two weeks of annual training at Fort Hill.

"The goggles turn night into day," Hubbard said, fastening the device to his flight helmet so he could see in the dark. "Once you fly with goggles, you never want to fly at night without them."

Resembling a small pair of binoculars, the goggles amplify light a thousand times. Darkness so thick you can't see more than a few feet with the naked eye is transformed by the goggles into a greenish scene with almost the intensity of daylight.

"The goggles let us fly at night down in the trees and we can see where we're going. But also we can fly with just about all of the lights out on the aircraft. The enemy might hear us, but they can't see us," Hubbard said.

A call came over the radio that the three-member crews of each aircraft had finished "goggling up," and the flight of Hueys lifted off into the dark.

Using only dim position lights to mark each helicopter, the flight slowly wound its way at treetop level toward Rte. 301. Then the search began for a friendly position along the southern edge of the highway. It would be marked with five tiny lights putting out less light than a flashlight and invisible from the air to those not using goggles.

It took a couple of passes before the lights were spotted and the helicopters swooped in to pick up the 29th Division soldiers who were to be carried to another location at the southern edge of the Caroline County Army post.

The military first used night vision goggles for tank drivers. With increased emphasis on the belief that future wars will be fought under cover of darkness, the Army has modified the devices for use by copter pilots.

Training to fly with goggles is not easy. The Virginia Army National Guard, one of the leaders in the nation in making use of the special gear, requires each pilot to take a two-week, full-time course and then use additional flight periods with an instructor to gain proficiency.

"Flying under the goggles is definitely stressful," said Hubbard, pointing out one of the safety concerns of such flight. With a narrow 40-degree field of view, goggles require the pilots and aircraft crew chiefs to always move their heads, scanning from side to side. Depth perception also is affected.

The whirring Hueys were airborne again, gently swinging back and forth along the treeline of Rte. 301, the divided highway that cuts the post in two. Tonight the flight would travel down the eastern side of Fort Hill and then along the southern edge to the landing zone where the troops would jump out and take up fighting positions.

With no moonlight to help the goggles work at their best, the helicopters groped in the darkness. The lights of a landing zone soon flashed into view through the goggles. But the crew would learn by radio that it needed to go farther west to another landing zone.

Chief Warrant Officer Jerry W. Bonham of Richmond said he loves flying using goggles, "because they're a great challenge. It's a better way of getting the job done." Bonham, 41, is a full-time instructor pilot for the guard's Army Aviation Support Facility at Richmond International Airport, where the 76th Company trains.

Sgt. Keith Vance, 25, of Fort Monroe flies as a crew chief aboard one of the Hueys. His job is to help do maintenance on the helicopter when it is not flying and assist on flights with navigation and loading and unloading the aircraft.

"The goggles ensure a safe flight at night for us," Vance said.

"Goggle flying is some of the most demanding flying I've done since I flew in combat," said Hubbard, a Marine pilot in the Vietnam War. "It's living close to the edge."

He lined up the flight for a final approach into the landing zone farther west. Slowly the trail of helicopters angled toward the ground.

In a few minutes, the infantry troops were back out into the night and on their way.