A Heliborne Strike in South Vietnam in 1963
American pilots of the Utility Tactical Transportation helicopter platoon left their quarters for the briefing area. As they would fly the five armed escort helicopters, the briefing had to be detailed and explicit. The UTT briefing was followed by a briefing from the transportation company of Piasecki H-21 "Shawnee" troop carriers that their Bell UH-1A and UH-1B "Huey" helicopters supported.
The operations officer gave the briefing for the day's strike. Three UH-1As and two UH-1Bs comprised the escort for the H-21s carrying South Vietnamese troops. After the Vietnamese troops were landed, all aircraft returned to the load zone, to rearm and refuel. Then the H-21s might make two more trips to the landing zone with full loads of Vietnamese soldiers, with five UH-1s supporting them as before.
With the H-21s at the loading zone, there was an early morning briefing by the H-21 company commander, an American, prior to the first strike. Flight routes and formations were discussed, along with frequencies and call signs. Vietnamese who acted as flight observers on the UH-1s were also carefully briefed.
The H-21 troop carriers took on their loads of Vietnamese soldiers - ten men with their equipment into each big helicopter. The armed escort took off, alert to cut down any Viet Cong who might be hiding in the ever-present jungle. The five tough little Huey choppers circled to take their places as protectors of the air fleet setting out for the landing zone.
The pattern of flight began to evolve. In flight formations from loading zone to landing zone, the H-21 troop carriers flew in groups of five, with one minute of flying time between groups. The helicopters in each grew flew in a staggered pattern - not one behind the other, but separated by the width of two ships.
In Vietnam in 1963, when the distance to be flown was more than fifteen miles, the military expedient of flying at an altitude of 1,500 feet had been adopted, departing from the standard "on the deck" treetop level. This was because of a limited number of heavy caliber weapons among the Viet Cong.
Protecting the formation were five armed escorts. Two of them escorted the leading pack, parallel to the last H-21 of the group and about 300 yards away on either side. From this position they could look down on whoever or whatever might direct fire on their charges. The three other armed escorts were stacked some five or six hundred feet above the formation, so placed that the tailing UH-1 would have the last H-21 of the final group and all its fellows under constant surveillance. Experience showed that five, or at the most six, armed escorts were sufficient to protect from five to thirty H-21s at the landing zone.
The platoon leader of the armed escort was always in one of the three UH-1s stacked high above the formation. When the formation was from five to ten miles from its destination, it was guided to the landing area by a U.S. Army Cessna L-19 "Bird Dog", which flew two or three thousand feet high, on a deceptive course. Its pilot was the American operations officer of the H-21 company to which it was attached. By voice radio, the L-19 guided the battle fleet down to treetop level, then lined it up for an accurate entry into the chosen area.
As the formation made its final approach, all pilots received the precise directions they needed. The two foremost armed escorts moved forward until they were perhaps a half-minute ahead of the H-21s. Both UH-1s then swept down the landing zone at from 50 to 75 feet elevation, the height depending upon the surrounding trees. When they reached the far end of the landing zone, each UH-1 turned and began an elliptical course that bracketed the field and and covered its edges.
There, the UH-1B's four traversable M60 machine guns would give a devastating reply to Viet Cong fire. With this reassuring sight before them, the pilots of the first group of H-21s brought in their ship, maintaining the staggered positioning in their pattern of landing.
Simultaneously, the three other UH-1s moved forward at 500 feet height and flew a circular course that covered all the landing areas. This completed the patterns pursued in armed escort of the troop-carrying H-21 Shawnees, in flight and in the landing zones.
It took approximately ten to fifteen seconds to discharge the ten Vietnamese soldiers from each H-21. As the groups flew one minute apart, the pilots and crews were under pressure to see that this unloading was done smartly. Then, the troop carriers took off, well in advance of the H-21 group following.
Now, let's suppose that one H-21 was fired on when coming in and landing. The low-flying UH-1B closest to the H-21 that was under attack received the platoon leader's command. The UH-1B made its run on the Viet Cong hiding place, and the gunner, traversing the machine gun, poured fire into the area. Then, he flew up to join the daisy chain circling at the higher altitude. There, he was able to use the lethal rockets that were prohibited him at the lower levels, where he would be flying through the ricochet of his own rocket bursts.
The UH-1B on the other side of the landing zone continued to cover his assignment, until all the H-21s had left the area. The daisy chain technique was designed to maintain continuous fire on the Viet Cong, so that they never had a chance to come out from cover and fire. This pattern of protective fire was considered extremely effective. The "daisy chain" type of operation lended itself to such actions, which protected not only the H-21s, but also protected the UH-1s themselves. Fire from the Viet Cong on one landing of H-21s was rarely repeated on later landings.