All aircraft crews landing at Khe Sanh knew they could be the target of enemy small arms and indirect fire while sitting on the ground. Accordingly they minimized the ground times. Whenever possible, landing crews immediately turned off the runway into the cargo loading area. They maintained a slow taxi through the cargo area while simultaneously rolling the cargo pallets onto the ramp behind them. They then taxied back onto the runway for takeoff over the same end, but in the opposite direction from which they had arrived. The shorter-landing C-123s accomplished this routinely but the C-130, with its longer landing roll, usually had to add a 180-degree turn on the main runway. Ground times for landing, offloading, taxiing and takeoff ran on the order of three minutes. Once airborne, the aircraft maintained a hard turn and steep climb to the northwest. One crewman noted, “There was no feeling in the world as good as being airborne out of Khe Sanh.” Passengers on such flights sat on their flak jackets so as not to take home a rear-embedded souvenir.

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Enemy fire ended the C-130 landings and might have threatened the survival of Khe Sanh Combat Base. However, within three days of the February 13 decision that C-130s would no longer be allowed to land at the base, the Air Force started delivering C-130-size loads using both conventional airdrops and the low altitude parachute extraction system (LAPES). During this type of delivery, the aircraft made an approach to the eastern end of the runway under visual conditions, staying five to 20 feet off the ground at an airspeed of 130 knots. An extraction chute pulled the multi-pallet, interlocked load out of the aircraft. The last pallet landed first and then skidded down the runway. The runway required replacement of aluminum planking after a LAPES delivery, but the base continued to receive heavyweight and large-size cargo resupply.

The Air Force flew 37 LAPES deliveries into Khe Sanh, but it took some tragic experiences to get it right. The first attempt was a disaster as a chute malfunctioned and the load skidded into a medical station, killing three Marines. Three weeks later, the second such delivery was off-center and killed one Marine when the load hit a bunker. Following that, the Air Force changed the delivery procedure to a ground proximity extraction system (GPES), which used a hook dangling from the open ramp of the plane to engage a ground-embedded wire stretched across the runway—much like a Navy carrier landing. Of the 15 GPES deliveries made, two malfunctioned.

On the western end of Khe Sanh Combat Base and 500 meters west of the perimeter, a drop zone 750 meters long by 500 meters wide was established. Some 600 airdrops were made during the siege, 90 percent by C-130s and the rest by C-123s. All the drops were made in daylight but nine out of ten of them were made in bad weather with only a 3 percent malfunction rate.

The majority of the drops were made using the container delivery system. Instead of using chutes to extract large palletized loads, this system consisted of 1-ton loads, each with its own small chute. Each load was bundled or clustered with others and held in the aircraft by a gate. The drop altitude was 400 to 600 feet above the drop zone. The gate was cut at load release, while at the same time the pilot pulled a nose-up maneuver, causing the bundles to exit the aircraft by gravity. Rather than hanging in the air and drifting long distances in the wind, the load swung only once before touching down.

The airlift effort in the siege of Khe Sanh demonstrated what a well-trained, properly sized and equipped airlift force can do. The combination of aircraft and helicopters allowed U.S. forces to meet all of the varied requirements to keep Khe Sanh operating, despite the exceptionally hazardous conditions resulting from loss of runway length, enemy groundfire and continually bad weather. Historically, tactical airlift under siege conditions has had a very limited record of success. However, it worked at Khe Sanh.I

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