above TOE authorization. The U-1A proved to be a valuable addition to the brigade's aviation capability. There were 116 UH-1H aircraft assigned to the brigade with an aircraft availability rate of 72 percent, which was 2 percent above the 1968 availability rate and was also 2 percent above the USARV minimum acceptable availability rate. Throughout the year there was a direct correlation between the number of patients evacuated, hours flown, times hit by hostile fire and aircraft availability. However, there were other variables such as accidents, non-scheduled maintenance and parts shortages that contributed to the rate. Mainly because of the variables mentioned, the availability rate for December 1969 was 8 percent. On 8 June 1969, the 551st Transportation Detachment was assigned to the 45th Medical Company (Air Ambulance) for direct support maintenance. The assignment of the 551st Transportation Detachment has enhanced the maintenance capability by improving the quality of work and contributed to the timely completion of ma1ntenance. Aeromedical Evacuation Statistics 1969 (Note 1) Abbreviations: FWMAF=Free World Military Assistance Forces; ARVN=Army of the Republic of Vietnam S-2/Historian The S-2 Section activities remained essentially unchanged from 1968. In maintaining the 44th Medical Brigade personnel security program, the section handled approximately 700 requests from subordinate units for either security clearance validations or for USAIRR checks, gave an estimated 400 security briefings/debriefings to headquarters personnel and processed 21 requests for revocation of security clearances. Only one security violation involving classified documents was processed during 1969. The resulting investigation determined that no documents had been compromised. In late November 1969, the S-2 as project officer for the implementation of the NESTOR Secure Voice Program, published and distributed implementing instructions to brigade units. When implemented, this program gave brigade units the capability of communicating with tactical elements in a secure mode, thus preventing enemy forces from acquiring vital intelligence data. Throughout 1969, the S-2, as a member of the Command Inspection Team had been able to analyze procedures implemented at several commands and developed a standardized SOP to allow each unit to benefit from the experiences of others. In December 1969, a complete thirty-four-page checklist for all S-2 activities including personnel, internal, communications and physical security as well as historical activities was published as an additional guide, assuring compliance with all pertinent regulations. The implementation of brigade staff visits on a monthly basis to the major subordinate units and selected units of their command has