Talking Proud Archives — Military

LS-85, Airmen left out on the limb, a leadership failure

September 10, 2017

By Ed Marek, editor


My objective in this report is to address events leading up to the North Vietnamese Army (NVA) attack on Lima Site 85 (LS-85) in northeastern Laos in March 1968 that put it out of commission and killed 13 Americans from the USAF. This was the largest ground combat loss of USAF people in the Indochina War.

This is, frankly, a tragic story. As you read ahead and learn the raw facts as they unfold, I ask you pay particular attention to the magnificent valor of those who fought against great odds, and also recognize those who attempted to thwart this tragedy long before it unfolded. The net result will be a recognition of monumental service and sacrifice about which we can and should talk proudly. That despite the terrible losses.


Lima Site 85 (LS-85) was a clandestine CIA-USAF location in northeastern Laos on top a 5,860 ft. mountain known as Phou Pha Thi, Phathi for short. Laotians knew it as "The Sacred Mountain" and "the Rock." This is a Google Earth view of the entire mountain to give you an idea about the mountain and its near environs. It was on a ridge that extended from the Northwest to the Southeast.

The word
"Phou" means mountain. "Pha" usually means the mountain has very steep precipices; and the word "Thi" usually refers to flatter land.

I want you to know in advance two points about this mountain and the attack before digging into this story:

  • The west side is the area where NVA sappers scaled sheer cliffs to attack, an avenue of approach thought impossible.
  • The southeast side is more shallow and fades into a plain. This was thought to be the most likely avenue of approach, is where defenses were set, and is the avenue of approach used by the NVA infantry backing up the sappers.

One geographic description of Phathi Mountain goes like this:

"It is the highest peak in the region. All four sides of the karst are sheer cliffs that are between 50 and 200 meters high. From about mid-way between the base and the summit of the mountain, the sides were formed by 75 degree to 80 degree cliffs, and in some spots 85 degree to 90 degree cliffs. The peak of Phathi Mountain is at least 3-4 kilometers from the surrounding peaks."

Not only was it high, it was isolated. The terrain was rugged with dense mountain forests throughout most of the province.

John T. Correll, editor-in-chief,
Air Force Magazine, wrote “The Fall” for the April 2006 edition. He said “the drop on three sides (of the mountain) was nearly vertical.”

Keep that in mind. Three sides nearly vertical. The southeast side sloped toward a plain or plateau to its east.

In her book
Tragic Mountains: The Hmong, the Americans and the Secret Wars for Laos, Jane Hamiton-Merritt wrote that Air America Captain Fred Walker called the mountain “the battleship.” It was surely that.


Phathi was located in Houaphanh Province, Laos, one of the most remote provinces in the country. During the American Indochina War, this province served as a haven for indigenous communist Pathet Lao revolutionaries who sought to overthrow the Royal Laotian Government (RLG) and convert Laos into a communist country. The province bordered on North Vietnam. It was therefore of great interest to it.

I need to say that if you were to research Laos during the American Indochina War, you would find many sources, including official ones, calling Houaphanh Province, Sam Neua Province. I believe that to be incorrect. Sam Neua is a city, a district, and provincial capital of Houaphanh Province, but it is not by itself a province. So I will use Houaphanh.

The Pathet Lao (Lao Nation or Land of Laos) movement was founded by a Laotian prince while he was in North Vietnam. It was committed to the communist struggle against colonialism. It joined with the North Vietnamese Viet Minh to fight the French, and in 1953 accompanied a Viet Minh invasion of northern Laos, after which they both stayed there. The Pathet Lao remained glued to the North Vietnamese Army (NVA), which was the follow-on to the Viet Minh, in the war against the US, the Republic of Vietnam (RVN), and the RLG. As a result, the NVA presence in the province was strong. Sam Neua served as the Pathet Lao headquarters and governing seat. It is the only city of note in the province. LS-85 was about 21 miles west of Sam Neua.


The site was in the heart of enemy territory. LS-85 at Phathi Mountain was about 120-160 miles (depending on what source one uses) miles west-southwest from Hanoi, North Vietnam (NVN).

CIA had a command site down the hill from the summit. CIA paramilitary and Hmong officers used this site as a Hmong staging base and to communicate orders to Hmong forces in the field.



CIA also had a rudimentary 600-700 ft. landing strip (landing zone - LZ) about 200 yards down the mountain that served as a staging base, a supply point used by USAF Pony Express clandestine CH-3C helicopters, and CIA Air America helicopters. It also served as a refueling station for USAF search and rescue (SAR) helicopters to pick-up downed crew in NVN or Laos. Two photos of it are shown here, both taken at the time LSA-85 was active with its navigational aids technologies. Furthermore, the LZ could be used to rotate crews back and forth to Udorn Royal Thai Air Force Base (RTAFB) located just south of Vientiane, Laos.


Finally, this same LZ could be used by short take-off and landing aircraft, such as this Porter aircraft which in this photo is located at another Lima Site.


I wanted to show you a photo of a Pony Express CH-3C. They were the main aircraft used to rotate crews from the mountain top back to Udorn. Pony Express missions were flown by the USAF's 20th Helicopter Squadron (20th HES) originally out of several airfields in RVN and then Udorn RTAFB from where it flew quite a bit over Laos. In 1968 the 20th HES was designated the 20th Special Operations Squadron (SOS). The Pony Express pilots flew anti-terrorist flights supporting the Thai Army and Lao insurgency fighters such as the Hmong. They conducted clandestine counterinsurgency infiltration and extraction flights into Laos and NVN. This unit is a story unto its own. Its helicopters had no US markings or insignia for the clandestine flights and no armor. They had no weapons until 1968 when a .30 caliber M-60 machine gun was installed at the cabin door.


This is a popular view of a key part of the Phathi Mountain. This feature and its location had virtual line-of-sight to Hanoi. That made it quite attractive to the USAF for installing sorely needed navigational aids. Such aids were needed to help US pilots attack targets in North Vietnam (NVN) and northern Laos.

The USAF installed two air navigation systems on this mountain top. These will be a main focus of this report. The USAF and others considered the site impregnable. It was not.

The first navigational aid installed was an AN/TRN-17 tactical air navigation system (TACAN) in August 1966. The second was a TSQ-81 radar command guidance system in September 1967. All of that equipment was located on the flat surface to the upper right of the above photo, next to the sheer cliff.


This photo shows everything on the mountain-top.


This photo shows a scale model of how the TSQ-81, generators, fuel and living quarters fit on a small area carved out of the mountain top. The TACAN was close by but not shown in this model.

All this air navigation equipment and the American operators on top of Phathi were there covertly, meaning not openly acknowledged. The TACAN operated from September 1966 through March 11, 1968. The more advanced TSQ-81 command guidance system operated from November 1, 1967 through March 11, 1968.


The core of this story will deal with the circumstances leading up to the lethal NVA attack against LS-85. NVA sapper forces unexpectedly scaled the steep cliff on the western side of Phathi and overran the LS-85's mountain-top air navigation facilities between March 10-11, 1968, killing twelve USAF-contractor radar operators. One USAF A-1 "Skyraider" fighter pilot was killed two days later while flying a search and rescue mission. The enemy put the site out of commission and the USAF destroyed it with air attacks a few days after the enemy overran it (photo used as sample illustration only).


Many sources reflect 11 USAF-contractor radar operators lost. Those sources in my opinion have failed to include CMSgt. Ricard L. Etchberger, USAF, who had been on the mountain, helped rescue several Airmen off the mountain under fire, was boarding the evacuation helicopter, was shot, and died on his way out from blood loss. He is number 12. He received the Medal of Honor (posthumous) for his valor and his name is on the Vietnam War Memorial. Four other USAF-contractor radar operators were rescued and survived.

I'll mention again, this was the largest USAF ground combat loss during the Indochina War.

John T. Correll, editor-in-chief, Air Force Magazine, writing “The Fall” for Air Force Magazine’s April 2006 edition, wrote:

“Even now, almost 40 years after the attack, questions and doubts persist about what happened that night on the mountain top.”

Linkages: Vietnam and Laos
US tackles the linkages
Challenges to Rolling Thunder pilots
TACAN at LS-85
TSQ-81 at LS-85: Process to make it happen
TSQ-81 at LS-85: Installation
TSQ-81 operations
Situation Assessment: Houaphanh Province
NVA plans attack
NVA moves to attack positions
US threat assessments - actions taken
The NVA attack
The aftermath