Erich Carter wiggles into the cylinder-like cockpit of the German-made glider and snaps four buckles over his shoulders and around his waist. His father, Jimmy, pulls the fiber glass cover down over Erich's head and locks it in place.

As son waits, father carries a 200-foot-long yellow rope down the runway. One end is attached to Erich's glider, the other to the tail of a 1950s-style Pawnee, once a crop duster, now a tow plane idling its 235-horsepower engine while waiting to take off from Front Royal-Warren County Airport.

With a thumbs-up to his 14-year-old son, Carter signals Dick Ault, a retired Air Force general and now the group's 82-year-old tow pilot. Ault's Pawnee starts to roll, dragging the 1,300-pound glider down the runway. The planes rise in tandem into the blueness above.

With the planes still connected, Erich--with his instructor watching from the back seat--steers the glider toward the summit line of the Blue Ridge visible across the valley.

"That's my boy!" shouts Carter. He and Fred Mueller, both Air Force-trained commercial pilots, squint up into the sun as Erich pulls a yellow knob in the cockpit, severing the connection to the tow plane and beginning his 20-minute silent odyssey.

The mountain backdrop, with its favorable winds, is a popular spot among glider enthusiasts. But as they have gathered in recent days, talk has centered less on flying conditions than on two headline-grabbing air crashes--one involving a glider, the other a single-engine private plane--on opposite ends of the continent.

Last Tuesday, two nationally recognized glider pilots--Donald D. Engen, 75, head of the Smithsonian's Air and Space Museum, and William Ivans, 79, an award-winning pioneer in the sport--were killed when their glider splintered in the Nevada desert. Three days later, John F. Kennedy Jr., his wife and sister-in-law died when Kennedy's Piper Saratoga plunged into the ocean off Martha's Vineyard.

Pilots who frequent the Front Royal airport say the two unexplained accidents make them even more aware of the safety precautions they take before and in flight. The deaths of Engen and Ivans--both experienced pilots--especially shook up glider pilots belonging to the 13,000-member Soaring Society of America, of which both had been leaders.

"It's nothing but tragic," said John D. Lewis, a neuropsychologist in Winchester who was at the Front Royal airport with the Carters last Thursday. The only comfort was that they "died doing what they loved, and not in a nursing home."

But Lewis, like Kennedy a beginning pilot, was at a loss for words yesterday about the second crash. "Aviation has a very long learning curve," Lewis said. "He was a novice pilot, too. It just says: Be careful."

As with the Kennedy accident, finding what caused Ivans's self-launching glider to spiral and plummet, breaking apart in midair, is now a matter for the National Transportation Safety Board.

Based on witness reports, Larry Sanderson, president of the New Mexico-based Soaring Society, said the cause appears to have been too much stress on the $250,000 glider. According to soaring experts, stress can happen when descent is too fast or the glider gets stuck in a strong weather pattern.

Whatever the reason, members of the "Thursday Fliers"--as Carter calls the group of glider pilots who gather each week at the Front Royal airport--were undeterred as they arrived last week, two days after the Engen crash.

"You're more likely to die in a car with no seat belt on driving to the airport than you are flying," said Carter, 44, of Herndon.

"If your butt is not on the ground, there's always a risk," said Jim Kellett, 63, a retired government worker who has taught gliding since the early '70s.

The number of glider accidents nationwide has varied over the past decade, averaging about 35 crashes and five deaths annually--the actual numbers recorded last year. This year could turn into one of the most deadly; already there have been 17 accidents and six people killed.

The last glider fatality in Maryland was in 1983 and in Virginia, 1991.

"This has been one of the worst accident years I've seen," said Kellett. "So far, there's no pattern to it. It's just been bad luck."

Most accidents result from pilot error. Ivans, who in 1950 was awarded the world's top soaring honor, had rejected suggestions he was a daredevil. "I take very few chances. I love competition, but I'm not foolish," he was quoted as saying in a 1986 newspaper interview. "And in gliding, danger is controllable."

Perhaps with that in mind, members of the Skyline club spent a few extra minutes last Thursday checking out their gliders before takeoff.

As a low hum settled over the runway, the men glanced up to watch Erich land. He banked sharply to the left and dropped his glider to about 200 feet in a maneuver required as part of his training for his license.

"That must be something to watch your son doing that," Mueller told Carter, who smiled broadly as the $30,000 glider approached, then made a bumpy landing on the scorched-dirt alternate runway.

Erich jumped from the cockpit and raced to a nearby tent, where he plopped down in a lawn chair. Popping peanuts into his mouth, he reviewed his landing, then reflected on Engen's fate.

"It can happen," he said. "People die."

Kellett, his instructor, was more reflective: "It's very sad to lose both of them because they were really fine people and fine pilots. Don's passion was to fly these things. Bill was a competitive, experienced glider. It's a tragic thing, but this sport can be like a black art."

Experienced glider pilots measure the wind and adjust for it. The most popular soaring spots for the nation's 18,000 licensed glider pilots are in the Southwest near the Sierra Nevada, where Engen's glider went down. Locally, the Blue Ridge and Allegheny mountains provide favorable winds for longer and higher-altitude flights.

There are a half-dozen chapters of the Soaring Society in Maryland and Virginia; memberships typically cost $500 up front and about $50 for a day of flying.

To become licensed, a glider pilot must log at least 25 hours and 100 flights, fly with an instructor and solo, and pass a written exam and a flight test, according to the Federal Aviation Administration.

Controlling a glider requires multi-tasking: Press down on two foot pedals to control the tail rudder. Use the stick between your thighs to control the dip of the nose. Remember, stay alert to oncoming planes! And don't forget to adjust the wing controls for a "thermal"--a condition caused by warm air rising from the ground and forming a column, like a bubble in boiling water.

"Pull the nose up and head straight for that ridge on the horizon," Kellett shouted from the back seat last week to a novice as their glider soared toward Massanutten Mountain at 3,000 feet. "No! No! Pull the stick up! No, up!"

Kellett quickly and firmly took the controls and veered the glider sharply to the right, heading for a fluffy cloud where he was certain a thermal column waited.

In seconds, the glider was below the puffy mass, its wings tilting at a 30-degree angle as Kellett swirled it in circles.

"Whee!! This is it! This is what it's all about!" he sang out as he pressed hard on the right pedal and jerked the stick in the same direction.

After 20 minutes, he brought the glider in smoothly.

Under the tent, Erich sat listening to the experienced pilots talk about catching "waves"--updrafts against the face of a mountain--and riding them. Glider pilots love to ride the wave at Massanutten Mountain, whose flat face stretches 45 miles between Front Royal and Harrisonburg.

Erich listened attentively. He has had only three weeks of lessons but already he's hooked on soaring.

"You can see everything up there," he said. "It's the coolest thing. Like my dad says, it's a legal high."

CAPTION: Jim Kellett, a gliding instructor for 33 years, soars a glider over the airportin Warren County, Va. "This has been one of the worst accident years I've seen," he said.

CAPTION: Jim Kellett looks over a Schleicher glider during a preflight check at Front Royal-Warren County Airport on Saturday.