Belated deliveries of aircraft delayed the commissioning of the world’s first transport helicopter squadron, HMR-161, until 15 January 1951 at El Toro. Lieutenant Colonel George W. Herring was designated the commanding officer and Lieutenant Colonel William P. Mitchell the executive officer. Nearly three months passed before the first three transport helicopters arrived. The squadron was gradually built up to a strength of 43 officers and 244 enlisted men with a full complement of 15 HRS-1 helicopters. These Sikorsky aircraft, designed to Marine specifications, were simply an enlarged three-place HO3S in configuration, with a similar main rotor and vertical tail rotor. About 62 feet long with maximum extension of rotor blades, the HRS-1 was 11½ feet wide with the blades folded. Following are some of the other statistics: Gross weight at sea level, 7,000 pounds; cruising speed, 60 knots; payload at sea level, 1,420 pounds; troop-lifting capacity, four to six men with full combat equipment or three to five casualties in litters.[283] Capabilities varied, of course, according to such factors as altitude, temperature, and pilot experience. [283] _Cavalry of the Sky_, 157. Marine Transport Helicopter Squadron 161 arrived in Korea on the last day of August, and by the 10th of September it had moved up to the front, sharing Airfield X-83 (see Map 18) with VMO-6.[284] The 11th was devoted to reconnaissance flights in search of landing sites, and on the 12th the transport squadron was ready for its first combat mission. A new means of logistical and tactical support that was to revolutionize operations and create front page headlines had arrived in Korea. [284] Auxiliary airstrips in Korea had an “X” designation and fields in the “K” category were major installations. Those in proximity to U.S. Army centers were designated “A.” Prior to the squadron’s arrival, the Division chief of staff, Colonel Victor H. Krulak, had held numerous planning conferences with Division staff officers, and preparations for the employment of HMR-161 had made noteworthy progress. Then General Thomas ordered executed the first operation of the squadron under combat conditions, and the major logistical problem of moving supplies and evacuating casualties was well on the way to being solved. At 1600 on 13 September 1951--a date that would have historical significance--Operation WINDMILL I was set in motion. Lieutenant Colonel Herring had attended the final planning conference at Division headquarters at 0830 on the 13th, and he was told that the operation would involve a lift of one day’s supplies to 2/1 over a distance of seven miles. The commanding officer of 2/1 was to select suitable landing points and the commanding officer of 1st Shore Party Battalion had the responsibility of providing support teams to operate at the embarkation and landing points.[285] [285] LtCol H. W. Edwards, interv of 20 Feb 61.