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.

Lima Site 85 DiagramOne 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.