Fifteen Miles on a Chopper
Part of my duty while I was assigned in Vietnam was to serve as a sort of a troubleshooter to correct problems which occurred with Air Traffic Control radio communications systems at about 10 different American Air Bases in the country. Ground transportation to most of these places was either nonexistent, unsafe for Americans, or too lengthy; so most of the time this duty required air travel to the problem location through the extensive passenger and cargo service provided by the US Air Force. On one occasion, however, I was ordered to go from Tan Son Nhut Air Base at Saigon to Bien Hoa Air Base about 15 miles north to troubleshoot a problem with the radio transmissions from their Mobile Radar Approach Control facility to aircraft on final approach. They were losing contact with aircraft within about 10 miles of the runway. Bien Hoa Air Base was the one destination to which I had taken ground transportation previously. In this case my transportation choices were to take an Air Force bus or to fly on a passenger aircraft. The bus was easily arranged but sort of mundane, and there was always the chance it would be attacked. The air passenger service required waiting in line at the passenger terminal and for the airplane longer than I wished. I knew of an Air Force organization on the flight line which flew helicopters. I had not previously flown in this type of aircraft, and thought it would be sort of a novel experience; so I contacted their Operations Office and found they had a scheduled trip to Bien Hoa. The Operations Officer said all I needed was my TDY orders and I could travel on their helicopter; so I packed my bags and arranged for our pickup truck to take me over to their office. Upon arrival the paperwork was completed, and, since the aircraft was to depart soon, I rode a bus out to the place on the airport where it was parked.
The helicopter was parked in a revetment at the side of an airport taxiway. Because of the possibility of rocket and mortar fire these revetments had been constructed to protect the combat aircraft on the base. The revetment was a steel and concrete-walled enclosure large enough to park an aircraft in. The walls were about 15 to 20 feet high. It was not roofed.
Exiting the bus I saw the blue Air Force helicopter, I think its designation was UH-1, parked there in the center of the revetment. It was attached by a power cable to the only other item in the parking area which was a ground power unit. The power unit was behind the helicopter and off to the left side. The crew chief slid the side doors open for the passenger compartment, and I got in and sat down on the web seats and fastened my safety belt. I sat on the left side. The pilot and copilot got into their seats in the front. In this helicopter the only division between the passenger compartment and the cockpit was a low canvas rail, so I was able to watch as the pilots went through their checklist and set the switches and controls. Soon the crew chief had the power unit running; the pilots started the jet engine, and almost immediately the rotor blades began to turn slowly, then faster and faster, and then became blurred as the RPM was increased. The crew chief shut down and disconnected the power unit, and got into his seat after closing the doors. So far I thought this to be a really neat experience which I was enjoying.
Very soon the pilot increased the power and, using the controls raised the machine about 2 feet off the ground. He stabilized in this position for a moment and then began moving very slowly forward out to the taxiway. When he had moved far enough forward that he could see past the end of the revetment wall, he looked to the left where a C-130 Aircraft was moving in our direction down the taxiway. The pilot then stopped the forward movement, and began moving backward to be sure he was out of the way of the larger aircraft. My uneasiness with helicopter flying began at this point. Although I am sure the pilot was completely aware of it, all I could think of was that he might be backing the tail rotor into the power unit which was still sitting in the revetment. I craned my neck, but could not see whether or not we were close to it. Within a few moments the C-130 taxied by, and after a short delay we began moving out to the taxiway. The C-130 had already reached the end of the taxiway and turned on to the runway.
At this point, as an experienced air passenger, I expected the helicopter to move down the taxiway and turn on to the runway and take off after the C-130 had departed. Still moving at a fast walk the pilot lifted us higher to perhaps 10 feet off the ground. Then suddenly the helicopter tilted forward at such a steep angle that I was looking right down through the windshield at the concrete, and began to accelerate rapidly. It seemed to me that the angle was so steep that surely the tips of the rotor blades in front would hit the surface. If I had not fastened my safety belt, I think I would have landed on the instrument panel between the pilots. Because I was not expecting this change it startled me, and I began thinking that maybe choosing this mode of transportation was a big, big mistake. Almost immediately as flying speed was reached the machine leveled and we were speeding down the taxiway. As we passed over the airfield fence our height was about 50 feet, and we were moving very fast.
My apprehension was relieved, and I began to think this was sort of fun. We flew on for a short time dodging around obstructions, and lifting over farm houses, until we were clear of the final approach path and other aircraft. The pilot then climbed to 1500 feet and turned north to Bien Hoa Air Base. At this point the flight seemed similar to that of a fixed wing aircraft, and I began to relax in my seat. Suddenly I heard: Whop, whop, whop, whop, whop. The sound dissipated, and returned: Whop, whop, whop. My first thought was that we were being machine gunned. We were in a war zone; rifle and cannon fire and the explosion of bombs were heard quite often, so my thinking was understandable. It was not unusual for the Viet Cong enemy to fire on aircraft approaching or departing the air field. Because the crew members did not seem concerned, and since no bullet holes appeared in the airframe I considered and realized the repetitive noise was the same as that heard when a helicopter was passing overhead, that it was caused by the rotor blades. It had not previously occurred to me that the same sound would be heard inside the helicopter. I have since read that the advancing rotor blade causes the noise by exceeding the speed of sound in some conditions, that the noise is sort of a mini-sonic boom. Obviously it is normal.
We didn’t get shot down and fifteen miles in a chopper does not take very long. Soon my experience was over, and we descended and landed at the helicopter pad at Bien Hoa Air Base. I got out of the helicopter and began my troubleshooting work. This was my first helicopter ride, and probably my last. When my work was completed I returned to my home base on the bus.
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