Desert Dust, Fire Humble U.S. High-Tech Strategy for Copter Operations at Night : Military: Sophisticated night goggles have been criticized as inappropriate for the Saudi terrain. But pilots say they are safer with them than without.

Using ultra-sophisticated vision equipment that seemingly dissolves the darkness, the huge Sea Stallion helicopters were to come whirling in through the desert night, landing with pinpoint precision to airlift a company of soldiers assigned to destroy an “enemy command post.”

The operation, a training exercise carried out in a remote area of Saudi Arabia, was supposed to embody one of the central principles of U.S. strategy in the Persian Gulf: that high-tech equipment and superior training will enable American troops to defeat a vastly larger Iraqi foe without incurring fearsome losses.

Instead, the exercise earlier this week turned out to be a humbling lesson of a sort the United States has learned on many battlefields before.

The mission, like many in actual wartime, was a race against time. The American troops had to get in and get out of the command post before Iraqi reinforcements could move in and wipe them out.

But trouble began to develop as soon as the Sea Stallions arrived at the blacked-out landing zone where the troops waited to embark.

Soldiers assigned to guide the choppers in were equipped with luminescent chemical lights. But nobody had completely reckoned on the dense cloak of dust that was kicked up by the choppers’ rotor blades, obscuring the guides on the ground.

“Those chem lights are about impossible to see,” complained one frustrated Sea Stallion pilot as he peered through his night vision goggles into the blackness.

Then there was the unexpected glare of burning gas at a nearby oil field, compounded by orders that the pilots must land facing the flames.

By the time the dust was settled and the pickup completed, the mission was nearly half an hour late. That meant that the Marines would arrive at the command post just in time to be blown away by arriving enemy reinforcements.

“You have just seen some of the limitations we’ve been talking about,” concluded a disappointed Lt. Col. T. J. Frerker, a Camp Pendleton-based Huey squadron commander.

If war comes to the region, American commanders want it to come at night, when U.S. aircraft would be far less vulnerable to hand-held Iraqi missiles.

But a series of nighttime accidents involving Army and Marine helicopters in Saudi Arabia has raised concerns about U.S. night-fighting capabilities in the unfamiliar, featureless terrain, where pilots have found it difficult to distinguish between land and sky.

As a result of the accidents, most of them affecting Marine helicopters, both services have imposed restrictions on night-flying operations. However, both Army and Marine commanders have said they would have no qualms about fighting a war at night.

In disclosing for the first time the restrictions on Marine operations, Brig. Gen. Granville Amos, assistant commander of the Marine Air Wing, stressed that their primary purpose is to keep helicopters “out of the dust” to avoid sand erosion of rotor blades and engines.

By permitting reporters to witness Marine night helicopter operations here, U.S. officers made clear that they hope to defuse a new round of criticism over the night goggles, stressing that pilots are well aware of the devices’ vulnerabilities.

“There’s a lot more to these things than just putting them on your face and going out flying,” Frerker, the Huey squadron commander, acknowledged.

The $25,000 goggles, known by their technical name of AN/AVS6, magnify available light about 25,000 times through 1.5 million microscopic glass tubes. The yellow-green image that the user sees is, in fact, a projection on a phosphorous screen.

In the first 45 days of their deployment here, Marines used the goggles in training missions even on moonless nights, when their capabilities are most limited.

But after the series of night-flying accidents, commanders ordered that pilots revert to a normal operations standard permitting training only when illumination from the moon is at least one-eighth its full strength.

On this night, however, the moon was more than three-quarters full, permitting the devices to function at what officers described as near-optimum levels.

In briefings before the exercise, pilots said their biggest problem in desert operations is dust, which can obscure their vision. Another problem, they said, is that too bright a light--such as the flame from flared gas at an oil field site--can wipe out vision by causing the goggles to “shut down.” The Marines said that these factors are “not problems,” but “limitations” with which they are learning to cope. They noted that the sandy, flat desert terrain also provides pilots with an advantage by reflecting more light than grass or forest.

From the cockpit of a Huey, pilots demonstrated the contrast between the yellow-green glow of a goggle-viewed world and the darkness of the desert without it. They discounted safety concerns and said that they believe that they are far safer using the goggles at night than not using them.

“It’s the difference between this,” Frerker said later, pressing his palms tightly over his face, “and this”--pulling his hands away and opening his eyes as wide as they could go.

Amid the dust and oil-fire glow of the sky above Landing Zone Eagle, however, the practical effect of wearing the goggles appeared to be something in between--similar perhaps to peering through a gauzy blindfold.

While Marines on the ground flashed their chemical lights again and again, hoping to launch their mock raid on an Iraqi command and control center on time, pilots circling in the air had to guess which was the proper pickup zone.

The first two choppers were set down in the wrong place, forcing the second pair to abort. Then the clouds of sand kicked up by the helicopters enveloped the landing zone. Even with night-vision goggles, the pilots could do little but orbit till the dust cleared.

Even after the exercise ended, one pilot was overheard on the radio asking another crew: “Did you guys ever see any chem lights in the pickup zone? We never did.”

Back at the airfield after the operation, pilots said the ground troops had ignited the lights too soon. By the time the helicopters arrived, the lights were too dim, they said. The lead Sea Stallion pilot, Maj. Rick Rogers, said he had given the Marines two boxloads of brighter lights in hopes of improving their visibility in the future.

But Frerker said the principal problem had been caused by bright lights, particularly the oil-field fire, which “pretty much shut down the goggles.” Later, he said, “We could not see each other through the dust.”

Even earlier in the operation, he acknowledged, the helicopters overshot a lake-bed landing site because they mistook its dark-sand characteristics for shadows cast by nearby highway lights.

Maj. Jim McClain, a Marine public affairs officer, noted that problems related to artificial light likely would be minimized in the blackout conditions of combat. But he acknowledged that fires could be a principal feature of the battlefield here, with Iraq having made preparations to set its defensive barriers aflame.

The bottom line, according to a rueful Frerker, is: “We need to practice it some more.”