Cambodian border which had been raided and burned by a force whose identity was undetermined. Fourteen Marine helicopters transported 168 troops from the 21st ARVN Division to the scene of the incident while two other squadron aircraft lifted the Deputy Commander of III Corps, the 21st Division Commander, and the Senior U.S. Advisor in III Corps, Colonel Daniel B. Potter, Jr., U.S. Army, to the village. The landing was uncontested as the marauding band had fled across the international border into Cambodia.
The conditions which confronted HMM-362 in the Mekong Delta during its first weeks of combat operations encouraged the squadron's pilots to experiment with new tactics. One such instance occurred in the first week of May in Ba Xuyen Province when the province chief requested that the Marine helicopters support his Civil Guard company in a raid on a fortified Viet Cong village about 12 miles southwest of Soc Trang. Because the objective was located so near the Soc Trang airfield, Lieutenant Colonel Clapp ordered an unusual technique used for approaching the landing zone. The flight would rendezvous over Soc Trang at tree-top level and proceed to the objective with the flight leader slightly to the rear and above the formation. From this vantage point the flight leader could keep the other aircraft in sight and exercise better control over each element of the flight. The success of the new procedure led Lieutenant Colonel Clapp to remark later that the technique was similar to "calling the plays from the grandstand." 18 It became another tactic available for the squadron's future use. In terms of lessons learned, HMM-362's most significant operation during its initial month of combat support came on 9 May. Twenty-three helicopters and two OE-1 observation aircraft launched from Ca Mau at 1100 for an assault on Cai Ngai, a Viet Cong-controlled village 21 miles to the south. At 1200 the helicopters began landing the ARVN troops in six landing zones which had been attacked only five minutes earlier by Vietnamese Air Force fighter bombers. Firing broke out even before the Vietnamese troops could jump from the helicopters. During this clash eight of the Marine aircraft were hit by small arms fire and two Vietnamese troops were wounded while still on board. One HUS, struck in the oil return line, was forced to land a few miles from the objective. Troops were flown in quickly to establish a perimeter around the downed aircraft while repairs were made. After the temporary repairs had been completed, its crew flew the helicopter to Ca Mau, where it remained until more extensive work could be accomplished. The other aircraft, including an OE-1, suffered only superficial damage and continued to support the ARVN operation.
From this encounter with the Viet Cong, the Marine pilots learned that air strikes conducted just prior to a helicopter landing in the heavily populated delta country tended to disclose the location of the landing zone to the enemy. In this instance the Communists had been able to reach the landing zone in the few minutes which elapsed between the last air strike and the arrival of the Marine helicopters. Following this experience, the Marines would no longer allow VNAF air strikes on landing zones prior to operations in the flat delta region.*
The Americans and Vietnamese, however, soon learned to use fixed-wing aircraft to support helicopter operations in another manner. By mid-June, FARM GATE T-28 Trojans (a single-engine two-seat trainer built by North American) modified to carry bombs, rockets, and machine guns were flying escort missions for the Marine helicopter squadron. This particular aircraft could fly slowly enough to cruise with the HUS yet fast enough to deliver an air strike en route to the objective and then catch up with the helicopter formation. Normally an element of two T-28s accompanied the helicopters and were used primarily to attack targets near the landing zone after the ARVN troops were on the ground. The placement of an American pilot-instructor and a Vietnamese student in the T-28, a requirement imposed by MACV, helped avert language problems which invariably developed when coordinating ARVN ground operations and U.S. air operations. The effectiveness of the escort tactic increased as the Marine and Air Force pilots became accustomed to planning, coordinating, and executing the missions.
The Marines quickly learned the value of utilizing the OE-1 in conjunction with their helicopter operations. Three single-engine, two-man aircraft,
*The development of helicopter tactics and techniques in Vietnam will be covered in detail in a separate monograph being prepared for publication by the History and Museums Division, Headquarters, U.S. Marine Corps.
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