January 12, 1968: High above the Laotian jungle, the 2 Antonov An-2 Colt biplanes banked to begin another run over the target. 120mm mortar shells fell from their bellies as rockets fired from wings, hoping to hit the small collection of buildings perched on the rocky ledge of a large mountain. The structures looked as out of place in this part of the world as the ancient aircraft sputtering back and forth above them seeking their destruction.

Then a helicopter appeared. An unmarked UH1 Huey. The planes broke off the attack and tried to flee. Their speed was no match for the Huey who easily caught them. A crewman leaned out the choppers open cargo bay firing an AK47 into the top of a Colt. It rolled over spewing smoke and plunged into the hills.

The chopper raced for another able to catch it quite easily and again the AK barked and the plane began its death plunge, its impact rolling a bright orange and black cloud high over the still jungle.

Back at the mountain top, the occupants dusted themselves off, tended their casualties, inspected the compound, and went back to work, having just survived the one of the most bizarre air attacks of the 3 year old American involvement in the Vietnam War.

No matter though, since the most important part of the mountain top outpost remained functioning: The TSQ-81 Tactical Air and Navigation radar (TACAN) that guided American strike aircraft to precise bomb release points in all-weather day and night over North Vietnam.

Known to few outside of those stationed there, the facility was called Lima Site 85.

One of the most closely guarded secrets of the war, the site was built on an outcropping of a 5,600 foot high mountain in Northeast Laos named Phou Pha Thi.

Origins of the facility began in summer 1966 when an earlier TACAN system was emplaced along with support personnel rotating every 2 weeks. The site was located just 15 miles from the North Vietnamese border and was dependent on weekly CIA helicopter flights to sustain it.

The Air Force technicians who ran the facility were required to wear civilian clothes because the U.S. was bound by a 1962 treaty forbidding foreign forces on Laotian soil. In fact, the personnel had to sign a form that temporarily released them from military service as long as they were in Laos.

In 1967, the site received the more advanced TSQ-81 radar and began functioning in November 1967 under the name Operation Commando Club with 19 personnel assigned.

From their consoles in the small olive drab buildings, controllers guided strike aircraft against targets that otherwise remained untouched due to weather. Successful sorties increased each month the radar operated, and by the end of 1967, was directing 55 percent of all bombing missions into North Vietnam.

All was not well behind the scenes; however, as reconnaissance aircraft showed the North Vietnamese building roads detached from main routes into the valley toward Phou Pha Thi.

Despite U.S. Ambassador to Laos William Sullivan desiring no personnel at the facility be armed, Major Richard Secord, in charge of security for the place, managed to obtain M16’s grenades Claymore mines and explosives to place on the radar in case the site was ever in danger of being captured. These measures provided the only security in the unlikely event the enemy ever came over the top.

Down in the lower part of the mountain and in the valley below, there was additional safety provided by CIA backed Laotian Hmong forces, though privately it was believed they would be unable to hold off a large sustained attack should one occur.

But, maybe the best defense of all wasn’t men or weapons, but the mountain itself. A sheer rock face almost all the way around with mostly steep drop offs. Anyone climbing would endure a tiresome journey up thousands of feet hauling weapons to storm the peak. No way could it be accomplished without incurring heavy losses. And as for climbing up the cliff nearest the site, this would entail the most perilous undertaking of all, as it was steepest in this area.

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Yes it was. And yet, it was done.

North Vietnam had eyed events at Lima Site 85 from its beginning, with increasing curiosity. It knew of the many CIA outposts in inaccessible areas supplied only by helicopter, but this went beyond a few thatched huts with tribesmen as guards. So as intelligence developed it into something more significant, the aforementioned air attack flown by North Vietnamese pilots occurred. When that failed it was decided something bolder, though riskier must be tried…


And so begins Mike Perry’s post about Lima Site 85, and the battle that saw the most USAF ground troops killed during the Vietnam War. We’re posting this over on SOFREP at 6am Eastern, Sunday Sep. 16.