In the second week of August, officers from HMM-261 and the task element’s staff (under the command of Colonel Gomez) met with American and Vietnamese officers at I Corps headquarters to plan a large-scale heliborne retrograde movement. The planned helilift was to mark the culmination of Operation LAM SON XII, a three-week long offensive by several battalions of the 2d ARVN Division against Communist infiltration routes in Quang Nam Province along the Laotian border. Although not encircled, the ARVN battalions had encountered increasing Viet Cong pressure since early August. I Corps authorities feared that unless their units were withdrawn promptly they might be cut off from the few landing zones that existed in the rugged operations area. As planned, the retrograde operation involved helilifting some 1,300 troops with their artillery and equipment to Thuong Duc, a government-held town situated 30 miles southwest of Da Nang along the Song Vu Gia. The operation plan called for the commitment of 20 Marine helicopters, 18 of which would participate in the actual troop lifts. The two extra UH-34Ds would be used in the event it became necessary either to replace helicopters assigned to the troop lift or to conduct search and rescue operations for downed aircraft. Three VNAF UH-34s and two U.S. Army unarmed UH-1Bs were designated by the I Corps headquarters to assist HMM-261 with the helilift. The Da Nang Air Support Operations Center assigned a variety of other aircraft to support the operation. These included two VNAF T-28s, one FARM GATE B-26, and two U.S. Army UH-1B gunships. These aircraft would share the task of providing close air support for the troop lift. A Marine O-1B was scheduled to perform weather reconnaissance missions. The entire air operation was to be coordinated from two aircraft. An American forward air controller in a VNAF observation plane was to direct all air strikes while overall control for the multiservice, bilingual effort was to come from a U.S. Air Force U-10 Super Courier. This six-man, single engine aircraft, which possessed an eight hour fuel capacity and carried three radios, would serve as an airborne air support operations center (Airborne ASOC). It would be flown by an Air Force pilot and would carry a Marine officer from the task element along with U.S. and Vietnamese representatives from the Da Nang ASOC. These officers would be in continuous radio contact with all aircraft in the operations area, and also with the U.S. Air Force liaison officer to I Corps who would be positioned with the ground troops.