Critics Cite Danger to Helicopter Crews : Goggles Give Pilot Night Vision at a Price

Times Staff Writer

More than a decade ago, at a time when military strategists were growing increasingly concerned about the vulnerability of their slow-moving helicopters, a new technology was introduced.

Its purpose: to give copters an edge in the dark.

Generals and field commanders alike realized that war was somehow changing. Foot soldiers now carried hand-held, infrared-seeking missiles that could be launched at a moment’s notice. The era of Vietnam, when helicopters could lumber along safely at 3,000 feet, out of the reach of small arms and machine-gun fire, was over.

If helicopter pilots were to stay above the battlefield, the reasoning now went, they would have to fly fast and low to the ground to avoid detection--and at night.


Look Like Binoculars

So Army and Marine helicopter pilots were told to strap on sets of heavy, awkward devices called night vision goggles. Under the right conditions, the battery-powered goggles, which look more like binoculars, can turn images of dark terrain into detailed, surreal, lemon-colored pictures that allow pilots to see almost as well at night as during the day.

Originally designed for tank and truck drivers, the light-amplifying goggles were made standard issue for thousands of helicopter pilots. But while many swear by the devices, the goggles by all accounts also restrict pilots’ peripheral vision and depth perception and have severe limitations when weather or other conditions curtail the available light.

Sometimes, critics say, these problems are insurmountable. In the last 11 years, flight crews equipped with goggles have been involved in 49 serious accidents, including the collision that killed eight servicemen during the ill-fated 1980 Iranian hostage rescue mission. Congressional staffers now put Army, Marine and Air Force goggle-related deaths at 137. In some accidents, copters have been flown right into the sides of mountains, as though the pilots had not seen a thing.

The issue goes before Congress on Tuesday, when a subcommittee of the House Armed Services Committee begins hearings on the safety of the goggles. Committee member Rep. Frank McCloskey (D-Ind.) says the Army, the largest user of the goggles, has given contradictory statements about them. McCloskey has three times called for a suspension of night training flights until safety questions are resolved.

“Given the continued wreckage and loss of life, it seems to be a reasonable request to temporarily suspend these missions,” McCloskey said. “My greatest concern is that the death and destruction will continue if steps are not taken to prevent it.”

For its part, the Army has officially attributed nearly all night vision training accidents to pilot error. Since 1978, the Army maintains, goggles have been a factor in only six of 39 serious accidents, Defense Week, a Washington-based newsletter, reported. But even as these reassurances were being made, congressional sources said, the Army was itself questioning the safety of an older model of goggles and urging that it be phased out and replaced by a newer, more efficient model.


Among crashes involving night vision goggles, the most infamous involved the aborted effort to rescue the 50 U.S. Embassy hostages in Tehran.

Eight CH-53 helicopters were ordered by President Jimmy Carter in 1980 to fly from the aircraft carrier Nimitz in the Arabian Sea to Tehran under the cover of darkness to rescue the hostages. To avoid radar, the flight was made at low altitude. But, according to transcripts from closed-door congressional hearings held in the aftermath of the mission, Marine pilots wearing the goggles flew into a giant cloud of sand suspended for more than 100 miles over the Iranian desert. One copter was forced to return to the carrier, and as the others began arriving at a refueling rendezvous point nicknamed Desert One, the operation was more than an hour behind schedule. Because of delays and mechanical problems, the rescue had to be called off.

Still, despite warnings that the goggles do not work in dense fog, dust, smoke or when the ambient light level is too low, pilots continued to wear them, with disastrous results. After the mission was aborted, a pilot wearing goggles was lifting off when his helicopter struck a C-130 transport plane, triggering a fire that killed eight servicemen.

Four years later, on March 24, 1984, another CH-53, with the four members of its Orange County-based crew wearing night vision goggles, slammed into a mountainside near Widibon, South Korea, killing the crew and 25 American and South Korean servicemen who were aboard. An investigation turned up no mechanical problems. That tragedy ended nearly a year of intensive training designed to show that helicopters and Marines could fly through mountain passes at night, avoiding enemy detection.

Helicopter Strikes Hill

And at 7:30 p.m. on Feb. 9, 1987, a Marine Reservist CH-46E copter took off from the El Toro, Calif., Marine Corps Air Station with a crew using night vision goggles. Eight minutes later it struck a hillside 200 feet below the top of the ridge. There was a full moon that night, presenting conditions ideal for the use of night vision goggles, but a resident near the crash site said the helicopter flew into a low fog bank just before it struck the mountain. Three Marines were killed.

Critics have seized upon these and other accidents.

“The goggles didn’t work very well in Iran, they didn’t work well in Korea and they don’t work well now,” said Arthur Conroy, a former Marine captain and helicopter pilot once stationed at the Marine Corps Air Station in Tustin, Calif. “I just think it’s crazy that they keep using them and people keep dying. There are better goggles available.”

After the Korean accident, which involved the loss of several close friends, Conroy wrote a nine-page letter to the Naval Safety Center in Norfolk, Va. Conroy, who previously had flown with the doomed Korea crew, recommended that the Marines stop using night vision goggles until limitations for the devices could be established. The 1984 letter also suggested that the Department of Defense do everything it could to speed up the purchase of a newer model of goggles then under development.

Conroy subsequently left the Marines--he says he was forced out after raising concerns about the goggles--but others involved with the goggles have expressed doubts as well.

Former Army Engineer Edward E. Firth, who was instrumental in developing the first night vision goggles, called the AN/PVS-5s--about 6,200 of which are still in use--said that model was designed for ground troops and tank and truck drivers and should not have been used at speeds of over 35 m.p.h.

Now retired from the Department of the Army and living in Punta Gorda, Fla., Firth is actively involved in night vision consulting for police agencies. When he was serving as civilian project manager for the development of the night vision goggles at the Army’s Center for Night Vision and Electro-Optics at Ft. Belvoir, Va., Firth voiced concerns to his superiors about the Army’s plans to use the goggles for aviation at speeds in excess of 100 m.p.h.

Once, Firth told The Times, he used the goggles at 75 m.p.h. at night on a section of Florida freeway that was not yet open to the public. He said he could keep the car on the road, but, “had a block of cement been dropped in my path I would not have seen it in time to stop.”

Although there are different models, all night vision goggles employ a cathode tube which converts rays of light to electrons which are multiplied before emerging at the other end of the tube on a miniature television-like screen. Powered by a battery and transformers, the key to the device is its ability to take a very dim light and make it into a bright picture at the other end of the tube.

Problems occur, according to pilots, when existing lighting deteriorates, as a result of rapid changes in the weather or when helicopters fly into sand, snow, fog or dust. The goggles are dependent on light from the moon, stars or nearby towns and cities. When those sources dim, goggle users see a picture that is increasingly grainy, with the image eventually disappearing altogether.

Early-model goggles involved a full face mask, which caused the lenses to fog up and pilots to suffer from feelings of being locked inside the mask. These models weighed more than two pounds, forcing pilots to find ingenious ways to hook the goggles to their flight helmets. Some pilots even strung large rubber bands from the cockpit ceiling to help hold up their heads during long goggle flights.

Pilots had to learn that goggles, much like the human eye, adjust slowly as they are turned from the dark outside to lighted instrument panels inside the helicopters. Before the helicopters were equipped with special lighting, crews would sit in dark cockpits with one of the pilots flying and the other checking the maps and charts and instruments with a small flashlight, all the while shielding the light from the goggled pilot. The skills of even the best pilots could be tested if the goggles or their batteries failed at a time when they were flying at less than 100 feet at speeds up to 120 m.p.h.

Early Problems Corrected

Today, according to Navy Lt. Rick Mason, an aeromedical safety officer with the Marine Corps night vision training facility here, the early problems surrounding the AN/PVS-5s have been corrected.

Now, the full face mask is gone, giving the pilots an opening just below the goggles that allows them to check their flight instruments for speed, altitude and attitude. The opening also eliminates the closed-in feeling that the full face mask gave pilots. New models, called AVS-6s and priced at about $18,000 each, as well as some of the older goggles, which cost about $5,000, can now be mounted with a flip up device that allows fliers to push the goggles up and away from their eyes quickly.

“They have their limitations,” explained Mason. “But within those limits there is no comparison between using the goggles at night and the naked eye. The goggles are like an aisle of vision in a sea of darkness.”

For both old and new goggles, according to Mason, these limitations include:

- A field of view limited to 40 degrees. Pilots overcome this by constantly scanning back and forth.

- Light for the goggles has to be at least equivalent to that cast off by 20% of a full moon. The newer goggles are much more proficient with less light.

- Pilots cannot see wires at night, forcing most goggle flights to be made over familiar routes.

- Problems with depth perception and distance that result from pilots seeing images in only the greenish-lemon hue. Objects also appear farther away than they actually are.

Designed for Aviators

Still, Mason believes that the older goggles have been improved and the newer models designed specifically for aviators are even better.

Mason works in Yuma at a night vision school that is part of the Marine Aviation Weapons and Tactics Squadron, the Marines’ equivalent to the Navy’s Top Gun school in San Diego. Instructors use infrared video, miniature terrain mock-ups and a helicopter cockpit to demonstrate various weather conditions, lighting and the limitations of both the newer and older night vision goggles. The training, which was called for after the South Korean accident, eventually will be required for all Marine fliers.

In the meantime, Col. John J. Barrett, commander of Marine Air Group 16 at the Marines’ Tustin helicopter base, hopes that public and congressional pressure does not lead to a moratorium or a ban on the use of the older night vision goggles while the military awaits delivery of newer models.

“I think it would be irresponsible if we went that way,” said Barrett. “We do not have the option to simply stop this training until conditions are perfect and we have flawless equipment. Our opposition, our potential enemies, probably won’t wait for us to catch up. They also want the upper hand. We must simply not give it to them.”

Mason, reflecting on the improved technology, believes the goggles will remain an important part of the Marine Corps.

“It’s a whole new ball game now,” Mason said. “Although earlier air crews voiced justifiable concerns about night vision goggle operations, those concerns have been acted on to make the goggles more compatible for aviation purposes.