, Security Officer, - ‘ ILLUSTRATION 3, opposite page, shows the organization of Headquarters, Task Group 7.4. In September, Lt Colonel Allen was requisitioned for duty at Head- quarters, USAF, Lt Colonel Paul H. Fackler (promoted to full Colonel in May 1954) succeeded him as Director of Operations. Prior to overseas movement, Major Harold R. Meadows replaced Colonel Fleming as Comptroller, B. ORGANIZATION OF TASK GROUP 7.4 In view of the relatively short time between IVY (the 1952 test) and CASTLE, Joint Task Force 132 desired that the Air Task Group from IVY be continued in an activated, but skeleton, status so that plans could readily be made for the coming operation. ; Early CASTLE planning, begun during the operational stages of IVY, was based upon the assumption that CASTLE would be a one-island operation based from Eniwetok, On 7 October Brigadier General Frederick E,. Glantzberg, Commander of IVY 's Task Group 132.4, forwarded CASTLE requirements to JTF 132 in order to further planning.” By October 1952, the concept of operations was changed by the AEG's desire to base the Air Task Group at Kwajalein, However, at a Kirtland conference on 25 November 1952, Dr. Alvin C. Graves of the Los Alamos Scientific Laboratory (LASL) stated that IVY results made a one-island operation more feasible and that the Air Task Group should be based at Eniwetok. The selection of Colonel Howell M. Estes, Commander of SAC'ts 12th Air Division, as Commander of the Air Task Group for CASTLE, was made in October 1952.° Colonel Estes was a replacement for Colonel Charles M. Bondley, another SAC Commander, who originally had been earmarked as art's [4