As the operations around Hue tapered off, General Cushman, on 29 February, directed General Tolson to take the plans for PEGASUS back off the shelf. During the first week in March, General Tolson met in Da Nang with Generals Cushman and Abrams for a discussion of the operation.[70] The mission was threefold: relieve the Khe Sanh Combat base, reopen Route 9 from Ca Lu to Khe Sanh, and eradicate any NVA elements within the area of operations. In addition to the three brigades of the 1st ACD, General Tolson was to assume operational control of the 26th Marines, the 1st Marines, and the 3d ARVN Airborne Task Force. D-day was tentatively set for 1 April--depending on the weather. With the basic directives, General Tolson returned to Camp Evans, and settled down to detailed planning with his division staff. During the next few weeks, there were numerous planning and coordination meetings with III MAF, PCV, the 3d Marine Division, 1st Marine Aircraft Wing, Seventh Air Force, and representatives of the attached units.(202) The logistics portion of the plan hinged around construction of a base and airfield near Ca Lu which could accommodate C-7 Caribou transports and later C-123s. Before work could be initiated, elements of the 3d MarDiv had to secure and repair the stretch of Route 9 between Ca Lu and the Rockpile so that supplies, fuel, ammunition, and construction material could be stockpiled. Once this was accomplished, a joint task force of engineers--the 11th Engineer Battalion, Fleet Marine Force, the 1st ACD's 8th Engineer Battalion, and Navy Mobile Construction Battalion 5--began construction of an airfield, parking ramps, logistical facilities, and defensive positions. By the time the lead assault elements were ready to jump off in the attack, the installation was 83 percent completed. The base was dubbed Landing Zone (LZ) Stud. On 25 March, D-6, the 1st Squadron, 9th Cavalry (1/9 CavSqd), operating from LZ Stud, began extensive reconnaissance in the PEGASUS area of operations to pave the way for the initial air assaults. The mission of the unit was "to find the enemy, destroy his antiaircraft capability, acquire hard intelligence for exploitation, and locate and prepare suitable landing zones." Since General Tolson had little concrete information on exact enemy locations, the activities of the 1/9 CavSqd were essential to the operation. The squadron fanned out from LZ Stud in ever increasing concentric circles under the cover of tactical air, B-52 strikes, and the 8-inch and 105mm batteries which had been moved to Ca Lu. During this phase, the air cavalrymen called in 632 tactical air strikes, 49 specially fuzed construction sorties (Daisy Cutters), and 12 Arc Light strikes on enemy antiaircraft positions, troop concentrations, and future landing zones.(203)