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The Battle for Lima Site 85

by unknown author

The U.S. facility atop of Phou Pha Thi, known as Lima Site 85, was the site of a major battle on 10 March 1968.

The Battle of Lima Site 85, also called Battle of Phou Pha Thi, was fought as part of a military campaign waged during the Vietnam War and Laotian Civil War by the Vietnam People's Army (VPA, then known as North Vietnam Army or NVA) and the Pathet Lao, against airmen of the United States Air Force 1st Combat Evaluation Group, elements of the Royal Laos Army and Royal Thai Border Patrol Police, and the Central Intelligence Agency-led Hmong Clandestine Army. The battle was fought on Phou Pha Thi mountain in Houpahanh Province, Laos, on 10 March 1968, and derives its name from the mountain top where it was fought, or from the designation of a landing strip 700 feet (210 m) in length in the valley below, and was the largest single ground combat loss of United States Air Force members during the Vietnam War.

During the Vietnam War and the Laotian Civil War, Phou Pha Thi mountain was an important strategic outpost which had served both sides at various stages of the conflict. In 1966, the United States Ambassador to Laos approved a plan by the United States Air Force (USAF) to construct a Tactical Air Control and Navigation (TACAN) site on top of Phou Pha Thi, as at the time they lacked a navigation site with sufficient range to guide U.S. bombers towards their target in North Vietnam. In 1967 the site was upgraded with the air-transportable all-weather AN/TSQ-81 radar bombing control system. This enabled American aircraft to bomb North Vietnam and Laos at night and in all types of weather, an operation codenamed Commando Club. Despite U.S. efforts to maintain the secrecy of the installation, which included the "sheep-dipping" of the airmen involved, U.S. operations at the facility did not escape the attention of the North Vietnamese and Pathet Lao forces.

Towards the end of 1967, North Vietnamese units increased the tempo of their operations around Phou Pha Thi, and by 1968 several attacks were launched against Lima Site 85. In the final assault on 10 March 1968, elements of the VPA 41st Special Forces Battalion attacked the facility, with support from the VPA 766th Regiment and one Pathet Lao battalion. The Hmong and Thai forces that were defending the facility were overwhelmed by the combined North Vietnamese and Pathet Lao forces. Phou Pha Thi is a remote mountain located in Houhpanh Province, north-eastern Laos. The mountain, which is about 1,700 meters (5,600 ft) high, was located within the Royal Laos Army's Military Region 2, and situated about 24 kilometers (15 mi) from the border of the Democratic Republic of Vietnam and 48 kilometers (30 mi) away from Sam Neua, the Pathet Lao capital. For the local Hmong and Yeo tribes that lived in the area, Phou Pha Thi was a place of religious significance; they believed it was inhabited by spirits who possessed supernatural powers to exercise control over the circumstances in their lives. The United States Air Force (USAF) considered Phou Pha Thi to be an ideal location for installing a radar navigation system to assist U.S. pilots in their bombing campaigns against North Vietnam, and along the Ho Chi Minh Trail.

Souvanna Phouma

Laos was considered a neutral country by the International Agreement on the Neutrality of Laos signed on 23 July 1962, so the United States military was prohibited from openly conducting operations in the country. For that reason, activities undertaken by the USAF in Laos had to be approved by the U.S. Ambassador to Laos William H. Sullivan. When the plan to install a navigation system on top of Phou Pha Thi Mountain was initially proposed, Sullivan opposed the idea as he suspected that Laotian Prime Minister Prince Souvanna Phouma, would not allow his country to be involved in an aerial offensive against North Vietnam. Souvanna did, however, permit the installation on the condition that it must not be manned by U.S. military personnel. In August 1966, the USAF installed a TACAN system, an autonomous radio transmitter that provided pilots with distance and bearing in miles relative to the station, on Phou Pha Thi. Then in 1967 under the codename Heavy Green, the facility was upgraded with the TSQ-81, which could direct and control attacking jet fighters and bombers to their targets and provide them with precise bomb release points. It began operating in late November 1967 as Operation Commando Club. To operate the equipment within the limitations imposed by the Laotian Prime Minister, USAF personnel assigned to work at the installation had to sign paperwork that temporarily released them from military service, and to work in the guise of civilian technicians from Lockheed Martin — the process is euphemistically called "sheep-dipping". In reality, they operated as members of the USAF Circuit Rider teams from the 1st Mobile Communications Group based at Udorn Royal Thai Air Force Base (RTAFB) who rotated to the site every seven days. Personnel working at the TACAN site were supplied by weekly flights of the 20th Special Operations Squadron based at Udorn RTAFB in Thailand operating under the codename Operation Pony Express, using Lima Site 85, the airstrip 700 meters (2,300 ft) in length constructed by the Central Intelligence Agency (CIA) in the valley below. Hmong General Vang Pao, who spearheaded the allied war effort against North Vietnamese and Pathet Lao forces in Military Region 2, was entrusted with the task of guarding the facility using the Hmong Clandestine Army alongside CIA-funded Thai Border Patrol Police forces. Though a substantial amount of resources were invested to maintain the facility, USAF command doubted Vang Pao's capability to hold the installation, and all equipment had explosives attached so, in the event that the site was overrun, it could be destroyed. By late 1967, Lima Site 85's radar directed 55 per cent of all bombing operations against North Vietnam. As USAF ground controllers were able to guide attacking aircraft against North Vietnamese targets in all types of weather, installation of the TSQ-81 radar system on Phou Pha Thi was considered by many to have been extremely successful during the final months of 1967. Yet a formerly top secret after-action report credited Commando Club with the following:
Against North Vietnam Nov '67 Dec '67 Jan '68 Feb '68 1-10 Mar '68
Total Missions 153 94 125 49 6
Missions Under Commando Club
20 29 27 3
Percentage Under Commando Club 13.0 21.3 23.2 55.1 50.0

Throughout this period, 427 strike missions were flown over the northern portions of North Vietnam. The facility at Lima Site 85 directed 99, slightly over 23 per cent of the total.
Barrel Roll area Nov '67 Dec '67 Jan '68 Feb '68 1-10 Mar '68
Total Missions 268 327 320 375 182
Missions Under Commando Club
1 67 23 142 165
Percentage Under Commando Club 0. 20.4 10.3 37.8 90.6

Successes of the system also brought about concerns for the personnel on the ground. Major Richard Secord, who was responsible for the security of Lima Site 85, was concerned about the safety of the unarmed USAF technicians who were working under disguise as civilians. Secord's concerns were justified by the events of 1967, as USAF reconnaissance aircraft that were regularly flying over north-eastern Laos showed that roads constructed by the North Vietnamese were approaching Phou Pha Thi. Activities associated with road construction were observed along Routes 6 and 19, which connected Dien Bien Phu in North Vietnam with Phou Pha Thi and Nam Bac in Laos respectively. Although Ambassador Sullivan repeatedly stated that USAF personnel at Lima Site 85 should not be armed, Secord decided to equip the technicians at the facility with weapons, so M-16 assault rifles, fragmentation grenades, concussion grenades and other small arms were brought in for use by the technicians.

Sensing that the North Vietnamese would attempt to destroy the facility, Secord advised the U.S. Embassy in Vientiane to evacuate all U.S. personnel from the installation. However, high-ranking U.S. officials insisted that Lima Site 85 should operate for as long as possible, as it was saving the lives of U.S. pilots each day that it remained in operation. In December 1967, the Communist military offensive in the region was signaled by a series of skirmishes. On 15 December, CIA-led Hmong reconnaissance patrols detected several North Vietnamese and Pathet Lao battalions moving against Nam Bac, then the stronghold of the Royal Laos Army. On 16 December, two Pathet Lao companies overran Phou Den Din, which was only 12 kilometers (7.5 mi) east of Lima Site 85. Shortly afterwards, Hmong units recaptured the site. Towards the end of 1967, U.S. controllers at Lima Site 85 directed F-4, F-105, and A-1 fighter-bombers based in Thailand and South Vietnam, to conduct air-strikes against North Vietnamese and Pathet Lao formations that appeared to be massing around the U.S. facility at Phou Pha Thi. Douglas A-26 Invaders were even called in to undertake night missions, targeting movements of the opposing forces on Route 6 and Route 19.

Operation Pony Express

On 14 January 1968, the situation in north-eastern Laos continues to worsen when an estimated four North Vietnamese battalions captured the Laotian Government stronghold at Nam Bac. Despite the growing threat from North Vietnamese forces, the U.S. military was not permitted to reinforce their facility on top of Phou Pha Thi Mountain due to political sensitivities. Instead, the defense of Lima Site 85 was entrusted to two CIA paramilitary officers who led about 1,000 Hmong soldiers, with 200 guarding the ridge-line and the remaining 800 soldiers were positioned in the valley below. They were reinforced by a Thai Border Patrol Police battalion of 300 soldiers. In the first week of 1968, the combined North Vietnamese and Pathet Lao forces probed Royal Laos Army positions in the region, by launching several artillery attacks. On 10 January, a Pathet Lao patrol was driven away from the area by the Hmongs. Fearing that the explosives attached to their equipment could be detonated by artillery strikes, the U.S. technicians dismantled all the charges and threw them over the cliff.

On 12 January, CIA spotters reported a four-aircraft formation flying in the direction of Lima Site 85. The aircraft spotted were Soviet-made Anotov An-2 biplanes; two aircraft flew towards Lima Site 85, while the other two split off. The Vietnam People's Air Force, in one of their few air attacks during the entire conflict, was attempting to destroy the radar at Lima Site 85. As the two AN-2s flew over Phou Pha Thi, their crews dropped 120 mm mortar shells through the aircraft's floor and also strafed their targets by firing 57 mm rockets from the wing pods. However, as the two aircraft flew back and forth to attack the facility, CIA officers and U.S. controllers at Lima Site 85 managed to call in a Bell UH-1D helicopter operated by Air America, which proved to be faster than the Soviet-made biplanes. Once the pilot of the helicopter, Theodore Moore, sighted the An-2s, he quickly chased the aircraft and pulled alongside one. Crew member Glenn Woods, who was armed with an AK-47 assault rifle, fired on the biplane and caused it to crash. Moore then chased down a second An-2 and Woods shot it down too. The two remaining An-2s that had observed the attack from a distance escaped from the scene without any damage. On the ground four Hmongs were killed by the attack, which included two men and two women, but the TSQ-81 radar and all associated equipment were not damaged. Shortly afterwards, the wreckage of one of the An-2 biplanes was put on display in front of the That Luang Monument, Vientiane's most important Buddhist shrine, as evidence of North Vietnamese activities in the country. Despite the severity of the attacks, the U.S. Embassy in Vientiane and the USAF did not change their strategy for the defense of Lima Site 85. Lieutenant-Colonel Clarence F. Blanton, the commander of USAF personnel at the facility, was not given the authority to supervise his own defenses or to order a retreat if the facility came under attack. Throughout January and February, intelligence collected by the Hmongs confirmed that a major assault on Lima Site 85 was in the making, but nothing was done by Sullivan or the U.S. military to strengthen the facility.

On January 1968, the situation in north-eastern Laos continues to worsen when an estimated four North Vietnamese battalions captured the Laotian Government stronghold at Nam Bac. Despite the growing threat from North Vietnamese forces, the U.S. military was not permitted to reinforce their facility on top of Phou Pha Thi Mountain due to political sensitivities.

North Vietnamese plan and preparations

On 18 February 1968, a North Vietnamese artillery survey team was ambushed near Lima Site 85 by Hmong reconnaissance teams, killing a North Vietnamese officer in the process. The dead officer, who was a major, carried a notebook which revealed a plan to attack Phou Pha Thi by using three North Vietnamese battalions and one Pathet Lao battalion. Consequently, U.S. personnel at Lima Site 85 directed 342 air strikes within 30 meters (98 ft) of their own facility to disrupt their opponent's build-up during the periods between 20-29 February. Unknown to the USAF, however, the Vietnam People's Army had also drawn up a plan to capture Lima Site 85 by deploying its Special Forces. The task of capturing the U.S. facility was entrusted to a platoon from the VPA 41st Special Forces Battalion, led by First Lieutenant Truong Muc. The platoon numbered 33 soldiers, and they were reinforced by a nine-man sapper squad and a communications and cryptography squad. Prior to their mission, Muc's soldiers had undergone nine months of special training which mainly focused on methods of fighting on mountain tops, scaling on cliff rocks, and jungle operations. They also conducted physical conditioning, to improve their physical fitness and stamina to undertake operations in the most extreme conditions on Laotian territory. On 18 December 1967, following their intensive training, soldiers of the VPA 41st Special Forces Battalion launched the first phase of their operation by conducting terrain reconnaissance and watching activities on Lima Site 85 to learn their opponent's routines. As part of the second phase, commenced on 22 January 1968, six North Vietnamese sappers were sent out to climb Phou Pha Thi Mountain, in order to pinpoint their opponent's positions in and around Lima Site 85, as well as their routes of withdrawal. On 28 February 1968, the North Vietnamese Special Forces completed their preparations, and they began marching towards their assembly point on March 1st. To maintain the element of secrecy, Muc was ordered to avoid contact with local civilians and opposing military forces. In the scenario they were engaged by opposing forces, the North Vietnamese would have to deploy a small force to deal with the situation, while the main formation would continue marching towards their objective on Phou Pha Thi. Once the North Vietnamese formation had arrived at their assembly area, they were to be divided into two assault groups. The first assault group, under Muc's direct command, was divided into five cells to attack key targets at Lima Site 85. Accordingly, Cells 1 and 2 were given the mission of capturing the communications center, with the latter given the secondary role of supporting Cell 3, which was given the main mission of seizing the TACAN site and eliminating all U.S. personnel. Cell 4 was ordered to capture the airstrip, and Cell 5 was placed in reserve to support other units. Meanwhile, Second Lieutenant Nguyen Viet Hung was given responsibility to lead the second assault group, and their mission was to destroy Thai positions. The attack would commence during the early hours of 9 or 10 March. To capture Lima Site 85, the North Vietnamese Special Forces were equipped with three Chinese-made K-54 pistols, 23 AK-47 assault rifles, four 7.62mm carbines, and three RPG-7 rocket propelled grenade launchers. Furthermore, there were 200 rounds of ammunition for each AK-47 rifle, six rounds for each RPG, 400 grams (14 oz) of explosives and six hand grenades. The weapons load, in addition to 15 days of rations and other personal items, required each North Vietnamese Special Force soldier to carry between 42 to 45 kilograms (93 to 99 lbs) worth of supplies. Shortly after the North Vietnamese Special Forces had arrived at the assembly point, they moved off to an undisclosed location for two days to test-fire all their weapons, and to ensure their explosives were in good working order. Then, in an attempt to fool Hmong and U.S. intelligence, the North Vietnamese made diversionary movements against Muong Son to cover their main assault. On 9 March, elements of the VPA 41st Special Forces Battalion arrived in the vicinity of Phou Pha Thi, where they made final preparations for their assault.

Fall of Lima Site 85

By 9 March 1968, the U.S. facility on top of Phou Pha Thi was surrounded by North Vietnamese and Pathet Lao units, with the VPA 766th Regiment and one Pathet Lao battalion totaling more than 3,000 men, were reported to be in position to attack Lima Site 85. Despite the seriousness of the situation around the facility, Sullivan did not issue an order for the evacuation of U.S. personnel from Phou Pha Thi. At around 6:00pm on 10 March, Lima Site 85 was subjected to a series of artillery barrages. Under the cover of the artillery bombardment, the North Vietnamese Special Forces sent a small team up the mountain to defuse the mines and quick-fuse grenades, to establish their routes of infiltration. Inside the facility, U.S. technicians immediately grabbed their weapons and ran into trenches and bunkers, thereby abandoning the very equipment which could enable them to call for air support. At 7:45pm the barrage stopped, and the U.S. technicians returned to their positions. The TSQ-81 antenna only received minor damages during the attack, and the U.S. suffered no casualties. However, the only 105 mm howitzer operated by the Hmongs received a direct hit, and was rendered ineffective. At around 8:20pm, Sullivan gave the U.S. commander at Lima Site 85 the authority to direct air strikes against targets at the lower slopes of the mountain, on the basis that the situation had become critical. About 20 minutes later, the 33-man North Vietnamese platoon began climbing up toward the U.S. facility at Lima Site 85. At 9:15pm Sullivan was considering evacuating all U.S. personnel from the facility at first light. However, officers of the Seventh Air Force contacted the U.S. Embassy in Laos and indicated that evacuation should only occur as the last resort, when the situation on top of Phou Pha Thu was no longer within their control.

At 9:21pm the North Vietnamese resumed their artillery attack on Phou Pha Thi, followed by several infantry assaults by the VPA 766th Regiment, which prompted Sullivan to order the evacuation of six technicians by 8:15am on the next morning, from a contingent of 19 U.S. personnel. Starting at 1:00am on 11 March, the North Vietnamese Special Forces moved into their assigned positions in order to launch their attack. About 2:00am, a U.S. adviser at the airstrip reported to Secord and CIA officers at Udorn that he heard gun-fire on top of Phou Pha Thi, and communication with the U.S. technicians at Lima Site 85 was completely cut off. Afterwards, Secord briefed U.S. A-1 Skyraider pilots in Thailand on the situation at Lima Site 85 to familiarize them with friendly positions around the facility, so they could cover the evacuation of U.S. personnel and support the Hmong's counter-attack.

About 3:00am Cell 1 moved to within 150 meters (490 ft) of their objective, with Cell 5 positioned behind them. At the same time, the commander of Cell 4 decided to maneuver his unit to the west side of the airstrip instead of the east side as originally planned, because the terrain on the east side was higher and was covered by buildings. Precisely at 3:45am, Cell 1 moved to within 30 meters (98 ft) of the communications center, when they bumped into a Hmong outpost. Both sides exchanged fire, and the outpost was destroyed by a grenade while the Hmong soldier guarding the post ran away. Shortly afterwards, a soldier from Cell 1 fired an RPG-7 grenade which immediately destroyed the TACAN antenna. Within 15 minutes, Cells 1 and 2 had secured the communications site. Signaled by the explosion of Cell 1's RPG-7 round, Cell 3 immediately attacked the TACAN installation by firing one of their own RPG-7s, which destroyed the electrical generators. Upon hearing the noise of explosions, the U.S. technicians who were on duty rushed out the front door of their operations building where they were met by North Vietnamese gunfire. Blanton, the U.S. commander at Lima Site 85, was killed alongside two other U.S. technicians. Those who were not killed retreated to the west side of the mountain, where they hid on the edge of the cliff. From their hideout, the U.S. technicians fired on the North Vietnamese with their M-16 rifles and hand grenades. At 4:15am, in response to the gunfire from the U.S. technicians, Muc ordered Cell 5 to reinforce Cell 3, and they captured the TACAN installation at 4:30am after 45 minutes of fighting. Meanwhile, Cell 4 had much greater difficulties in their attempt to seize the airstrip, where they were blocked by a Hmong mortar position. Le Ba Chom, the commander of Cell 4, was isolated from the other three soldiers of his cell. To avoid being captured alive by the numerically superior Hmong forces, Chom and his soldiers held onto their position and fought till daybreak. At 5:15am Sullivan, from the U.S. Embassy in Vientiane, decided to evacuate Lima Site 85 and he gave a signal to U.S. pilots at Udorn to begin the operation, which was due to start at 7:15am. However, Sullivan did not realize that U.S. technicians were no longer in control of their TSQ-81 equipment.

Starting at around 6:00am, Pao's Hmong soldiers launched a counter-attack against North Vietnamese positions at the communication center, which was guarded by Cells 1 and 2, but their attacks were repelled and the North Vietnamese held their positions. With the final Hmong counter-attack on the communication site defeated at 6:25am, Cell 2 was ordered to support Cells 3 and 5 in their fight at the main TACAN installation. By 6:35am, the North Vietnamese established full control of the TACAN site. At the airstrip, Cell 4 was encircled by an estimated two Hmong platoons, but Chom and his unit were able to fight their way out by taking full advantage of the rough terrain which covered their positions. Later, Cell 4 linked up with other units at the TACAN site. At sunlight, Air America helicopters hovered over Lima Site 85 to start the evacuation, which was covered by USAF A-1 Skyraiders. Immediately, Hmong soldiers and their CIA commanders rushed the TACAN site and shouted to the U.S. technicians that help was coming. In response, the North Vietnamese Special Forces organized a defense around the TACAN site, and hid their dead and wounded comrades under the large rocks which dotted Phou Pha Thi.

While U.S. fighter-bombers strafe the TACAN site, the Air America helicopter landed on the airstrip and they picked up two CIA officers, one forward air-controller, and five technicians who were hiding during the fire-fight. Later during the day, Air America was able to recover or account for eight of the dead U.S. personnel on Lima Site 85, along with a number of wounded Hmong soldiers. By midday, Lima Site 85 was fully controlled by the VPA 41st Special Forces Battalion, and they held the facility until 14 March, when they withdrew from the area.


Just before midday on 11 March, the USAF turned their attention from looking for their missing personnel to that of destroying the TSQ-81 Commando Club radar, along with all the documentation and operation information left behind at Lima Site 85. Between 12-18 March, the USAF conducted a total of 95 strike sorties against the radar site, and on 19 March, an A-1 fighter-bomber destroyed every building at the old facility. In addition to the destruction of their own radar equipment, the USAF bombing of Lima Site 85 may have also had the effect of obliterating the bodies of deceased U.S. personnel who were left behind at the site. In the days following the loss of Phou Pha Thi, Sullivan reflected on the disaster at Lima Site 85 and commented that the U.S. technicians operating there should have been evacuated on 10 March, when it became amply clear the North Vietnamese were preparing to launch their assault.

For the USAF, the loss at Phou Pha Thi was not a result of intelligence failure, because they had been provided with accurate information from the very start. Instead, it was clearly a failure of command and control, as the U.S. personnel and their Hmong allies were not permitted to carry out their own defense in order to hold the radar facility. The Battle of Lima Site 85 resulted in the largest ground combat loss of USAF personnel during the Vietnam War. A total of 12 U.S. personnel were missing or killed as a result of the fighting on Phou Pha Thi; 11 were killed or missing on the ground and one was shot dead during the evacuation process. The single fatality occurring during the evacuation was Air Force Chief Master Sergeant Richard Etchberger who was awarded the Medal of Honor posthumously in September 2010 for his role in helping four injured airmen into the evacuation helicopter lift sling. The total casualty figure for all North Vietnamese, Pathet Lao, Hmong, and Thai units is unknown. According to official Vietnamese history, the VPA 41st Special Forces Battalion lost one soldier killed and two wounded in their fight for Lima Site 85. Against those losses, the Vietnamese claimed a total of 42 Hmong and Thai soldiers were killed, and a number of others were wounded. Furthermore, a large cache of weapons were captured which included one 105 mm howitzer, one 85 mm artillery piece, four recoilless rifles, four heavy mortars, nine heavy machine guns, and vast amounts of ammunition. The North Vietnamese victory proved to be a significant one, as they had succeeded in knocking out a major asset of the USAF, which had inflicted heavy damages to North Vietnam's limited industrial infrastructures. The fight at Phou Pha Thi, which was part of a larger military campaign waged by the North Vietnamese and their Pathet Lao allies, marked the beginning of the Communist dry-season offensive against Laotian Government forces in north-eastern Laos. By September 1968, the strength of North Vietnamese and Pathet Lao forces in the Sam Neua area were estimated to have numbered more than 20 battalions.

Against such heavy odds, General Vang Pao insisted on recapturing Phou Pha Thi, which the U.S. Embassy believed was unnecessary. On 20 October 1968, Pao returned to Laos following a month-long vacation in the United States, and he immediately planned his next move. However, by that stage the Hmong Clandestine Army had lost about half their strength due to heavy casualties. On 1 November 1968, Pao launched Operation Pig Fat in an attempt to retake Phou Pha Thi, but the operation quickly turned into a rout for the Royal Laos Army and the Hmong guerrillas, and Phou Pha Thi was never retaken. Although airpower was to be a major factor in the defense of Lima Site 85, it could not be applied without limitations and restrictions. The defense of Lima Site 85 was not the sole task of limited air resources in the Southeast Asian conflict. For example, during this same period, the 1968 Tet Offensive was underway in South Vietnam, the Marine outpost at Khe Sanh was under siege, and there existed an unprecedented flow of enemy logistic traffic which had to be interdicted. The Lima Site 85 had provided direction to about a quarter of the USAF missions over North Vietnam and Barrel Roll from November 1967 to 11 March 1968. No other facility existed to provide a similar coverage over these areas. While this loss was a serious blow to the USAF air effort, it was not crippling.

Eleven of the twelve USAF personnel lost on the day of the battle were listed first as missing-in-action (MIA), then later as killed-in-action / body not recovered. Between 1994 and 2004, 11 investigations were conducted by both Joint POW/MIA Accounting Command (JPAC) and unilaterally by Lao and Vietnamese investigators on both sides of the border. In 2002, two of the former VPA soldiers who had taken part in the attack told investigators that they threw the bodies of the Americans off the mountain after the attack as they were unable to bury them on the rocky surface. In March 2003, JPAC investigators threw dummies over the edge at those points indicated by the VPA soldiers while a photographer in a helicopter videotaped their fall. That pointed the investigators to a ledge, 540 feet (160 m) below. Several mountaineer-qualified JPAC specialists scaled down the cliffs to the ledge, where they recovered leather boots in four different sizes, five survival vests, and other fragments of material that indicated the presence of at least four Americans. On 7 December 2005, the Defense Prisoner of War / Missing Personnel Office announced that the remains of Technical Sergeant Patrick L. Shannon had been identified and were being returned to his family. On 14 February 2007, the remains of Captain Donald Westbrook, who had been shot down in 1968 while searching for possible survivors of the battle, were positively identified from remains which had been returned in September 1998. A memorial to the USAF airmen killed and missing at Lima Site 85 and other Combat Sky Spot airmen is co-located on Andersen Air Force Base, Guam, with the memorial to Operation Arc Light airmen.