The month of February also witnessed the largest helicopter supply lift in Korea, HAYLIFT I, the previous September, had tested the feasibility of transporting Class I, III, and V supplies to a frontline infantry regiment for five consecutive days. HMR-161 and the 7th Marines had turned out an excellent test performance of the rotary craft in this logistical operation. It then became the task for the infantry and helicopters to run a resupply operation for two frontline regiments for a five-day period. HAYLIFT II, conducted 23–27 February, was the code name for this test. Both the planning and execution of the February operation followed the general pattern of HAYLIFT I, but on a much larger scale. As in September, division ordnance and service battalions moved the supplies to helicopter loading zones near Lieutenant Colonel Carey’s HMR-161 air strip. It had been estimated that 130 tons each day would have to be lifted to supply the two MLR regiments, the 7th and 5th Marines. On the first day, this figure was exceeded by 30 tons. A request by A/1/5 on 24 February for support during an emergency operation necessitated additional ammunition[330] and helicopters to be diverted from those resupplying the 7th Marines. By the third day, a backlog of supplies had accumulated in the loading areas. In order to eliminate this buildup and to replace ammunition expended that morning by 1/5, HMR-161 on 25 February transported 200 tons in a single day, thereby establishing a new record. This represented 392 lifts made in 138.4 hours flying time. Maximum time for unloading a chopper was 54 seconds; the minimum, 28 seconds. [330] The following month, HMR-161 engaged in a four-day ammunition resupply operation for the division. Except for one day, the 22d, all available helicopters were assigned to that mission, beginning 20 March. HMR-161 also had a new CO by that time, Colonel Owen A. Chambers who had taken over from Lieutenant Colonel Carey on 15 March. The last two days of HAYLIFT II, although less eventful, contributed to a resupply tonnage record five times greater than that set by HAYLIFT I. On the last day, when fog grounded their aircraft for a second time during the morning, Marines were again reminded of an operational limitation of the helicopters. In the end, though, the accomplishments far out-weighed this shortcoming. During the five days, a total of 1,612,406 pounds of supplies had been lifted to the two frontline regiments. Not one crewman or helicopter was lost. The operation contributed significantly to the February record for the greatest number of combat hours (765), total hours (1,275.5), combat flights (575), and total flights (1,183) flown by HMR-161 for any one-month period during the Korean fighting. For the rest of the war, the February 1953 gross lift of 2,018,120 pounds would also rank as the largest amount transported by HMR-161 for a single month.