When Donald Worley volunteered for a sensitive assignment called Project Heavy Green, his wife had to sign a secrecy agreement too. Don, an Air Force man, was to be temporarily relieved of duty to take a civilian job with Lockheed Aircraft. He would be running Lima 85, a radar base in Laos, whose neutrality prohibited U.S. military presence. No one was to know. Lima 85 was on a peak in the Annam Highlands near the village of Sam Neua on a 5860 ft. mountain called Phou Pha Thi. The mountain was protected by sheer cliffs on three sides, and guarded by 300 tribesmen working for CIA. Unarmed US "civilians" operated the radar which swept across the Tonkin Delta to Hanoi. For three months in early 1968, a steady stream of intelligence was received which indicated that communist troops were about to launch a major attack on Lima 85. Intelligence watched as enemy troops even built a road to the area to facilitate moving heavy weapons, but the site was so important that William H. Sullivan, U.S. Ambassador to Laos, made the decision to leave the men in place. When the attack came March 11, some were rescued by helicopter, but eleven men were missing. The President announced a halt in the bombing of North Vietnam. Donald Westbrook was flying one of 4 A1E's orbiting on stand-by to search for survivors of the attack at Phou Pha Thi when his plane was shot down March 13. Westbrook was never found. Finding no survivors, the Air Force destroyed Lima 85 to prevent the equipment from falling into the hands of the enemy.