The radar site was deep in enemy territory. The assumption was that it was impossible for attackers to climb the sheer face of the mountain.

The Fall of Lima Site 85

By John T. Correll

Lima Site 85 and the secret Air Force radar facility sat atop one of the highest mountains in Laos, 15 miles away from the border with North Vietnam. The site was defended by a force of 1,000 Hmong irregulars in the valley below, but a key element in its security was the mountain itself.

The drop on three sides was nearly vertical, and US officials did not believe the enemy could climb the cliffs. The fourth side of the mountain was fortified.

The assumptions were wrong. On the night of March 10-11, 1968, under cover of a massive artillery and infantry assault on the mountain, a team of North Vietnamese sappers scaled the cliffs, overran the radar site, and killed more than half of the Americans they found there.

For years thereafter, the fate of Lima Site 85 was classified as top secret. When reports finally began to emerge, they were riddled with gaps and inaccuracies. Even now, almost 40 years after the attack, questions and doubts persist about what happened that night on the mountaintop.

The story of Lima Site 85 began with the weather.

With the onset of the northeast monsoon in October, the weather over North Vietnam turned unfavorable for air operations and it did not improve again until April. This was a big problem for Rolling Thunder, the air campaign against North Vietnam from 1965 to 1968.

At the time, the US had two all-weather strike aircraft: the Navy’s A-6 and the Air Force’s B-52. Only a limited number of A-6s were available, and for reasons of political reluctance in Washington, the B-52s were held to bombing near the Demilitarized Zone. That left it up to F-105s and other tactical aircraft to carry the war to the north, and during the monsoon, they could strike targets around Hanoi for only four or five days a month.

A solution of sorts appeared in 1966 with an adaptation of Strategic Air Command’s radar bomb scoring system. This modification, called the MSQ-77, guided aircraft to a precise point in the sky where ordnance was released. It wasn’t pinpoint accuracy, but it was good enough for targets such as airfields and industrial areas.

By 1967, the Air Force had five MSQ-77 radars working in South Vietnam and one in Thailand. However, none of these sites covered the North Vietnamese heartland around Hanoi. That required putting the radar where it would have an unobstructed line of sight to the airspace over Hanoi. Also, the target area had to be within 175 miles of the radar, which was the effective range of the system.

Such a place existed at Phou Pha Thi, a mountain in Laos 160 miles west of Hanoi. The Air Force already had a TACAN navigational beacon in operation on the rim of the mountain at an elevation of 5,580 feet. That was high enough to give the radar a straight shot to Hanoi.

There was also a rough landing strip, Lima Site 85, on the flank of the mountain. It was one of several hundred such Lima sites built all over Laos by the CIA’s proprietary airline, Air America, to supply Hmong hill tribesmen fighting the Communist Pathet Lao. By strict definition, the Lima site was the airstrip, but the area around the TACAN was generally referred to as Lima Site 85 as well.

A portable version of the MSQ-77 radar, the TSQ-81, could be broken down into sections and transported to Phou Pha Thi by helicopter.

In Hostile Territory
There were several problems with Lima Site 85 as a location for a radar bombing system.

According to a 1962 Geneva agreement, which the United States had signed, Laos was a neutral country. No foreign troops were supposed to be there. The US promptly withdrew its forces in 1962, but only about 40 of the 7,000 North Vietnamese troops in Laos ever went home. Rather than confront the North Vietnamese in Laos openly, the United States chose instead to give covert assistance to the Royal Laotian government. (See “The Plain of Jars,” June 1999, p. 78.)

As the conflict gathered momentum, the CIA and Air America supplied and trained the Hmong hill tribesmen, who were the best fighters in the Laotian Army. The war in Vietnam spilled over into Laos as well. By 1965, US aircraft were flying regular combat missions against targets in Laos. In the north, Operation Barrel Roll supported the government troops fighting the Pathet Lao, and in the south, Operation Steel Tiger interdicted the Ho Chi Minh Trail in the Laotian panhandle.

It was a secret war in the sense that the American public was not told about it, although Congress and the news media knew generally what was going on.

Lima Site 85 was situated in the part of Laos where the enemy was strongest. The mountain was 15 miles from the North Vietnamese border and less than 30 miles from the Pathet Lao capital of Sam Neua.

William H. Sullivan, the US ambassador to Laos, was wary of installing a bombing radar in Laos, and he was adamantly opposed to bringing in US combat troops to defend the site. If there were to be a TSQ-81 system at Phou Pha Thi, the defenders would have to be Hmong, trained and organized by the CIA (which was known in Laos as CAS, or Controlled American Source). For further defense, US air strikes could be used against any forces that threatened the site.

If worse came to worst, air rescue could bring the people out. The assumption was that there would be plenty of time for helicopters to land at the helipad, 300 yards down the ridge from the radar site, and extricate the technicians.

Sheep Dipped
At the urging of the Air Force and the Joint Chiefs of Staff, the United States took steps in 1967 to establish a TSQ-81 facility at Phou Pha Thi. Sullivan obtained concurrence—with conditions—from Souvanna Phouma, the Prime Minister of Laos.

“If the unit were to be installed, Souvanna suggested that it must be done without his knowledge,” Sullivan notified Washington in June. “Technicians servicing the site would have to be civilians or military personnel with civilian documentation.”

In July, Souvanna agreed to the proposal. Sullivan reported, “I assured him that: a) All USAF markings would be removed from equipment, b) Detonators would be affixed to permit immediate destruction in case of imminent danger, [and] c) Personnel would be under civilian cover.”

The Air Force rejected the idea of sending airmen into Laos with fraudulent ID. If they were captured in “shallow cover,” pretending to be civilians, they would have no protection under the Geneva Convention as prisoners of war.

Instead, volunteers would go through a process known in the shadowy world of special operations as “sheep dipping.” They would leave the Air Force, be hired by a legitimate civilian company, and go into Laos as employees. When their mission was over, they would be welcomed back into the Air Force. If they were captured or killed, their families would be covered by company or Air Force benefits.

Lt. Col. Gerald H. Clayton, who had extensive experience with MSQ-77 radars, would head the team. He and Lt. Col. Clarence F. “Bill” Blanton handpicked the airmen who would be asked to volunteer. They had known most of them for years.

The proposition was put to the selected candidates at Barksdale AFB, La., in September 1967. Forty-eight of them—four officers and 44 enlisted members—volunteered for the program, which was named Heavy Green. They were separated from the Air Force and employed by Lockheed Aircraft Service Corp., a subsidiary of Lockheed Aircraft Corp. While they were in the program, they would be paid by Lockheed, which also gave each of them a substantial life insurance policy.

Their wives were brought to Washington, briefed, and required to sign security agreements to keep the program secret. SSgt. Herbert A. Kirk’s wife, a German national, could not be granted security clearance and she did not attend.

Additional space was cleared atop Phou Pha Thi to make room for the radar installation, and an Army CH-47 Chinook cargo helicopter brought in the larger pieces of Heavy Green equipment. The expanded TSQ-81/TACAN area reached about 150 feet inward from the southwest rim. Beyond that point, the mountain rose in a tangle of rocky outcroppings and scrub brush to a peak 1.6 miles to the north.

The radar was rigged with explosives so it could be destroyed before the enemy could capture it. Heavy Green took over the TACAN as an additional duty. The radar bombing system went operational on Nov. 1, 1967.

Targeting the North
The Heavy Green team deployed to Udorn Royal Thai Air Base in northern Thailand and set up shop in two quonset huts in the Air America compound. The sheep-dipped airmen lived in rented housing off base. Around Udorn, they wore uniforms and carried military ID. Ironically, this was a cover role, since they were, in fact, civilians, having separated from the force.

When they flew to Lima Site 85 for two-week rotational tours of duty, they wore civilian clothes and carried their Lockheed ID.

Clayton was commander of Det. 1 of the 1043rd Radar Evaluation Squadron, which had headquarters at Bolling Air Force Base in Washington, D.C. He also was manager of the Lockheed field service group at Udorn.

The clandestine nature of the site led to fuzzy lines of control and responsibility. The Air Force was the main user of Lima Site 85 services, and the daily tasking for support of bombing missions came from 7th Air Force in Saigon. However, Sullivan was the ultimate authority over US activity in Laos and everybody knew it.

The Geneva agreement prohibited a US military headquarters in Laos. Therefore, under a “Country Team” policy, military affairs were directed by the ambassador. Sullivan was vigorous in the exercise of his authority, and the war in Laos was marked by a power struggle and antagonism between Sullivan and the military. Various arms of the US government had an interest in Project Heavy Green, but none of them was exclusively in charge.

The Pathet Lao were active in the vicinity of Phou Pha Thi and they regularly clashed with the Hmong, who were trying to keep communist forces from using the mountain valleys as a route into central Laos. Concern about the vulnerability of Lima Site 85 was offset by its operational value to the Air Force.

The site was guarded by a force of about 1,000 indigenous troops, mostly Hmong but including some Thais. Of these, 200 were in the immediate vicinity of the radar site with the other 800 on the lower parts of the mountain. Two CIA paramilitary officers were stationed at the CAS area, just south of the helipad. The approaches to the radar site were strewn with mines and concertina wire.

Nobody expected the enemy to get that far. From the bottom of the mountain, rocky slopes extended about halfway up at angles of 45 to 60 degrees. The rest of the way to the top was much steeper, rising in places at 85 to 90 degrees.

In response to an inquiry from 7th Air Force, the office of the air attache in Vientiane reported that the approaches to the top of Phou Pha Thi were “virtually a vertical climb and those avenues which can be traversed are heavily mined.” Phou Pha Thi could be taken if the enemy concentrated a large force—about four battalions—charged in full strength, and was willing to accept heavy losses, the attache office said.

The northeast monsoon of 1967-68 was especially severe. For the 18 weeks the Lima Site 85 radar was in operation—that is, from Nov. 1, 1967, to March 10, 1968—the Air Force relied on it for 23 percent of the air strikes in the northern part of North Vietnam. Operations conducted under the direction of Site 85 were called Commando Club.

Bombed by Biplanes
The first attempt to destroy the radar site came from the air. About 1 p.m. on Jan. 12, two Russian-built An-2 Colt biplanes made three bombing passes against the summit of the mountain.

The biplanes had a World War I look to them, but they were really not that old. The An-2 first flew as a crop duster in 1947. Cruising speed was below 150 mph, which probably was an advantage in this case because the biplanes were dropping improvised munitions through tubes in the floor.

The “bombs” were converted 120 mm mortar rounds that would arm in the slipstream and detonate on impact. The brunt of the attack fell on the CAS area, where shiny rooftops apparently drew the attention of the An-2 pilots. They did not target the TSQ-81 facilities until the final pass, and the bombs they dropped there all missed. The attack killed two Laotian civilians and two guerrillas, but it did no damage to the radar site.

An Air America Bell 212 helicopter, the civilian version of the Huey, was on the helipad at the time of the attack. The crew leaped aboard and gave chase. The helicopter was faster than the biplanes. As it flew past the An-2s, the flight mechanic blasted them with a submachine gun, firing out the door and hitting both of them. One An-2 crashed and burned, and the other crashed 16 miles to the northwest while trying to clear a ridge. The rudder from one of the biplanes was recovered and taken to the Air America base at Long Tieng for a souvenir.

The security challenges increased. On the evening of Jan. 30, the enemy pounded the southern end of the mountain with a 30-minute mortar attack. It did not amount to much and was written off as a probing attack.

By the middle of February, the enemy was on all sides of the mountain, about seven miles away. On Feb. 18, the Hmong wiped out a small party of North Vietnamese five miles southeast of the site. Among those killed was an officer who carried a notebook with plans for a coming attack on Phou Pha Thi. It said three North Vietnamese battalions and one Pathet Lao battalion would take part. The notebook contained the word “TACAN” in English and it had the exact location.

Lima Site 85 continued to direct bombing in North Vietnam, but, by February, more than half of the Commando Club strikes were flown against the enemy forces surrounding the mountain itself.

In late February, the CIA said that the security of Phou Pha Thi could not be predicted beyond March 10, and Sullivan sent a message to the Air Force warning that the site probably could not be held much longer.

The Air Force did not want to pull out. “Due to the desirability of maintaining air presence over [the North Vietnamese] during present inclement weather period, Site 85 probably would not be evacuated until capture appeared imminent,” 7th Air Force said in a March 5 message to Pacific Air Forces officials. “The fact that complete security could not be assured in the original plan is noted.”

Up to then, the Heavy Green personnel at the mountain had not been armed. In March, the embassy approved the issue of M-16 rifles, although the technicians had not achieved proficiency with them before the big attack came.

On March 11—the TSQ-81’s last day of operation—19 Americans were at Phou Pha Thi. Sixteen of them were Heavy Green personnel. The radar technicians were divided into two shifts, one led by Blanton (a sheep-dipped lieutenant colonel and Clayton’s deputy) and the other by Stanley J. Sliz (a sheep-dipped captain). Also at the site were a combat controller who had been sent from Vientiane to direct local air strikes and the two CIA paramilitary officers in their own building near the helipad.
The Sappers Attack

The force that hit Phou Pha Thi on March 10 consisted of between five and seven battalions, amounting to some 3,000 troops. Mortar, artillery, and rocket rounds began falling about 6 p.m. The enemy was firing on the mountain from the north and east.

The barrage stopped at 7:45 p.m., having inflicted some damage on the living quarters, the TACAN antenna, and a defensive gun position. Fighting continued at the lower elevations. Blanton’s team took the duty in the TSQ-81 van, while Sliz’s team was sent to rest in preparation for duty later. With their quarters vulnerable to shelling, Sliz and his group decided to spend the night on one side of the mountain, where they would be sheltered from the artillery that was firing from the opposite direction.

They took their sleeping bags, weapons, and survival radios with them, descending about 20 feet over the side by means of a makeshift ladder fashioned from a C-130 cargo net. That took them to a small cliff, partially protected by a rocky overhang. The airmen often went there when off duty because it was a change from the tight confines of the radar site. There was nothing below except a straight drop to the valley below.

Through the night, A-26 bombers and F-4 fighters struck the attackers repeatedly, guided by Blanton’s radar team. Sullivan considered evacuating the site, but the Air Force held to its position of evacuating only as a last resort if the situation became untenable. At about 9:30 p.m., Sullivan decided that nine of the Americans would be brought out at first light the next morning. That, as Sullivan said later, would be “one day too long.”

Before midnight, 33 North Vietnamese sappers climbed the western side of the mountain, a feat that US officials assumed was impossible. The sappers had trained for months, practicing on karst peaks and the faces of rock cliffs. They emerged on the top of the mountain at a point between the radar buildings and a Thai guard post.

The sappers waited in hiding until 3 a.m., then began moving toward the Heavy Green facilities. They bumped unexpectedly into an enemy guard, who threw a grenade. The sappers immediately opened fire on the radar buildings with a rocket-propelled grenade launcher and submachine guns. “The Americans were taken by surprise,” the North Vietnamese report said later.

Eventually, the North Vietnamese discovered Sliz’s team on a rock overhang about 20 feet down from the top. The sappers shot down the side of the mountain with automatic weapons and lobbed grenades over the slope.

Several of the Americans on the ledge were killed outright. Sliz and John Daniel were wounded. However, CMSgt. Richard L. Etchberger was unhurt and, because of him, his wounded companions would live to be rescued. Etchberger kept the sappers at bay with his M-16 rifle.

At least eight Americans were still alive on the mountain. Etchberger, Sliz, and Daniel were on the ledge. The TACAN technician, Jack Starling, was by the TACAN, wounded and playing dead. Bill Husband was on top of the mountain, just north of Starling. The combat controller, Sgt. Roger Huffman, was near the helipad. The two CIA officers, Howard Freeman and John Spence, were at the CAS area south of the helipad.

Rescue
At 5:15 a.m., Sullivan decided the evacuation of all personnel would begin in two hours, at 7:15 a.m. Incoming fire stopped just before 7 o’clock. Air America and Air Force rescue helicopters were standing by, ready to go in, but they were drawing fire from the summit.

Hard fighting continued on the lower parts of the mountain. The senior CIA officer, Freeman, and 10 Hmong soldiers went to TSQ/TACAN area to determine the situation. Freeman got no response when he called out, but his party exchanged fire with the North Vietnamese attackers. Freeman was shot in the leg and several of the Hmong were killed. A flight of A-1E Skyraiders made a strafing pass over the site to brush back the enemy before the helicopters approached.

First in, at 7:35 a.m., was an Air America Huey from Long Tieng. Spotting the men on the ledge, the pilot pulled close to the cliff and the flight engineer brought the survivors up by cable. Husband ran to join them.

Etchberger helped Daniel and Sliz, who were wounded, board, then he and Husband went up the cable. Etchberger was no sooner inside the helicopter than ground fire came up through the floor, mortally wounding him. He died minutes later. (Etchberger was awarded the Air Force Cross, posthumously. It was presented to his wife, Katherine J. Etchberger, by Gen. John P. McConnell, the Air Force Chief of Staff, in a closed ceremony in the Pentagon Jan. 15, 1969. Present, in addition to the family, were Clayton and almost every senior officer on the Air Staff.)

At 8:20 a.m., an Air America helicopter took out Thai and Hmong wounded. Freeman went with them. A USAF Jolly Green Giant brought out more Hmong wounded at 8:46 a.m. At 8:54 a.m., Air America picked up Spence and Huffman. Husband told the rescuers that one more person, Starling, was probably still alive at the site. A Jolly Green Giant went to get him and picked him up at 9:46 a.m.

Of the 19 Americans on the mountain, eight had been brought out. Of the remaining 11, the first count was eight dead and three presumed dead, but that was updated by the Vientiane embassy within 24 hours: “Latest interrogation and discussion with survivors has led to a firm conclusion that three previously carried as missing were indeed seen dead by one or more survivors. Therefore, we are no longer carrying any personnel missing, but consider all of those who were not, repeat not, extracted, to be dead.”

In their report, which surfaced years later, the North Vietnamese claimed to have killed 42 men at the site and wounded many others, “primarily Lao and Thai soldiers.”

Fall of Site 85
The Hmong defenders around the site held the trail to the summit as late as 7:30 a.m., but they were badly outnumbered and the North Vietnamese and Pathet Lao force was too powerful. Phou Pha Thi soon fell to the enemy. In the furor of the attack, nobody detonated the thermite with which the radar had been rigged.

“Presuming those who were not evacuated on the morning of 11 March were dead, a fairly concentrated air effort was launched on that same day to destroy the technical and personal equipment left behind on Site 85,” the embassy in Vientiane reported.

Sullivan met with Souvanna Phouma and told him that Site 85 had not been destroyed but that Air Force napalm strikes were being delivered. “He urged me to destroy as much evidence as we can rapidly,” Sullivan said.

A message from the embassy on March 16 said that the next of kin had been notified of the “missing status” of the 11 airmen who were not evacuated. The message said the Air Force wanted to delay for a “reasonable period” or until confirmation of death before officially going from “Missing in Action” to “Killed in Action.” That change was made March 25, thereby authorizing insurance payments to the families.

The Heavy Green survivors were restored to membership in the Air Force. The families of the 11 missing men received payments from the Lockheed insurance policy, and, in 1969, all of them except Herbert Kirk were reinstated in the Air Force. Kirk’s wife did not have security clearance to be told about the classified project. Apparently, Kirk agreed that, in the event of his death, the government would stay with his cover story and not reinstate him in the Air Force. His family would rely on the Lockheed survivor benefits instead. This arrangement would be later overturned in court.

The North Vietnamese and the Pathet Lao moved to consolidate their victory. By September, they had more than 20 battalions in the Sam Neua area. Hmong Gen. Vang Pao launched a major operation to retake the mountain in December. His forces did recapture the landing strip, the helipad, and the CIA area, but they were unable to take the mountaintop. They fell back, and Phou Pha Thi was never recaptured.

There was no attempt to install another TSQ-81 in Laos. On March 31, President Johnson announced a partial halt of bombing of North Vietnam and made the bombing halt complete on Nov. 1. There was no longer a need for a radar to guide strikes in the north.

Questions in the Aftermath
The “Secret War” in Laos was publicly disclosed in 1970, but the announcement revealed nothing about Lima Site 85 and what had happened there. Up to then, the families had not been told much of the story. In 1970, an Air Force team, which included Clayton, visited the families and gave them more of the details.

One of the widows, Ann Holland, did not believe she was getting the full answers or the straight answers about the fate of her husband, TSgt. Melvin A. Holland. In 1975, she sued the Air Force and Lockheed for negligence. She said the government had not candidly informed her of the facts of his death. The suit lingered in the courts until 1979, when it was dismissed.

According to Timothy N. Castle, author of a deeply researched 1999 book, One Day Too Long: Top Secret Site 85 and the Bombing of North Vietnam, Ann Holland’s lawsuit alerted the Kirk family as to what had happened at Lima Site 85. Mrs. Kirk had never been informed of the operation because she had no security clearance. The Kirk family filed a lawsuit of its own. Not until then was Kirk’s membership in the Air Force posthumously restored and full military survivor benefits given to his family.

The 11 men not recovered from Phou Pha Thi, including Kirk, were awarded the Bronze Star posthumously in 1984.

The story came out in bits and pieces. Among the earliest public revelations was an official Air Force history of the war, published in 1977. It described the fall of Lima Site 85, but described it as a navigation facility, leaving out any reference to the TSQ-81 bombing mission. In 1978, Airpower in Three Wars, written by Gen. William W. Momyer, former commander of 7th Air Force, described the mission and operation of the site in some detail but did not mention its capture.

A 56-page official Air Force history of the loss of the site, written for internal use and classified Top Secret when it was completed in August 1968, was declassified in its entirety in 1988. It adds substantial detail but is marred by a number of factual errors. The history is now available on the Internet.

The North Vietnamese report—titled “Raid on the TACAN Site Atop Pha-Thi Mountain by a Military Region Sapper Team on 11 March 1968”—was published in 1996 and obtained and translated by the Department of Defense in 1998.

Castle interviewed dozens of survivors and former officials for his 1999 book. It filled in numerous details and identified mistakes in earlier works.

In recent years, there have been recurring reports that some of the technicians at Lima Site 85 were captured, not killed. A former high-ranking Pathet Lao officer told Castle that prisoners were taken. He, however, had not been present at Phou Pha Thi, and his statement was contradicted by the statements of others, including former enemy soldiers who were there. They said there had been no prisoners. The detailed North Vietnamese account of the attack, published in 1996, did not report any prisoners either.

The Department of Defense credited the statement of the American survivors and other evidence, including study of aerial photos of the site taken on March 11, and held to its assessment and carried the 11 airmen on its rolls as “Killed in Action/Body Not Recovered.”

Return to the Mountain
Since 1994, the Joint POW/MIA Accounting Command, headquartered at Hickam AFB, Hawaii, has interviewed witnesses and made trips to Laos and Vietnam, gathering information about the fate of Americans at Phou Pha Thi. Among those interviewed have been villagers who lived near the site and former enemy soldiers who took part in the attack.

Excavations at Phou Pha Thi in December 1994 and January 1995 produced no information about American casualties. In March 2003, however, acting on information from new witnesses, representatives of the command searched the summit, the eastern and western slopes, the western cliffs, and the slopes below.

Two former North Vietnamese commandos who took part in the attack showed the investigators three places where they had thrown bodies over the cliff. The investigators threw mannequins over the edge at those points while a photographer in a helicopter videotaped their fall. That pointed the investigators to a ledge, 540 feet below.

Mountaineer-qualified specialists scaled down cliffs to the ledge, where they discovered human remains, leather boots in four different sizes, five survival vests, and other fragments of material that indicated the presence of at least four Americans. The team worked in hazardous conditions, including strong winds and falling rocks, which constrained the search.

In December 2005, the Defense Prisoner of War/Missing Personnel Office announced the identification of the remains of TSgt. Patrick L. Shannon, one of the 11 airmen at Phou Pha Thi. Further excavation of the ledges is planned, assuming the willingness of the Laotian government to approve access to the site.

Today, commentaries on the fall of Lima Site 85 appear with some regularity in newspapers and military journals, but interpretations differ and the controversy continues.

The losses at Phou Pha Thi seem all the more tragic because, 20 days after the attack, the White House put an end to Rolling Thunder operations above the 20th parallel, of which the Lima Site 85 radar was a part, and the bombing of Hanoi came to a halt. The courage and sacrifice of those who died on the mountaintop stood in counterpoint to the strategic indecision and changing political winds in Washington.

John T. Correll was editor in chief of Air Force Magazine for 18 years and is now a contributing editor. His most recent article, “Determination of a Sandy,” appeared in the March issue.

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