thgt prevailed earlier. May and June were the peak months for the L~20's. In May, the L-20's flew 571 hours and 1,992 missions. 4,128 passengers and 8,575 pounds of cargo. These missions carried During the entire operation from March through August, these aircraft flew 2622° hours and carried 15,587 passengers and 5,210 pounds of cargo. See Figure 15 for a sum- mary of L-20 flying activities. Detachment #4 of the 24th Helicopter Squadron was enlarged from its permanent complement of four (4) aircraft to fifteen (15) aircraft for Operation HARDTACK. operation. These aircraft performed yeoman service during the The fifteen (15) were divided into a flight of six (6) H-19's and another flight of nine (9) H-21's, The H~19's were preferred for rad-safe sur- veys because the aircraft afforded greater protection from radiation and the H-21's were preferred for normal airlift because of their greater carrying capability.. The unique performance characteristics of the hélicopter made it an invaluable tool in the accomplishment of inter-island airlift at Eniwetok | in support of the scientific projects. The helicopters also consistently overflew their programmed flying hours. In spite of the high maintenance cost in man-hours to produce a helicopter flying hour, the in-commission rate of these craft was very high. The average of 69 hours per month for each of the assigned H-21's for the month of May is believed to be an Air Force record for helicopter utilization. The flow of normal scheduled traffic was smooth, interrupted only by weather. The special airlift requirements, however, were difficult during the first half of the operation due to Task Group 7.4 receiving late requests for scientific recoveries, and many other special missions, 169 AFWind