After the North Vietnamese Air Force’s first intercept of U.S. aircraft in April 1965, Hanoi’s leaders feared U.S. bombing strikes on their planes on the ground. Unaware that U.S. Rules of Engagement precluded an immediate counterstrike against the interceptors’ launch airfield, NVAF leaders ordered the planes to be moved to the mountains north and northeast of Hanoi shortly after landing, a challenge for transportation units and ground and air crews. Fortunately for them, Hanoi had just received some Soviet-built Mil Mi-6 “Hook” heavy-lift helicopters, which at nearly 20,000 pounds had enough lift capacity to transport a fully fueled and armed MiG-17, -19 or -21 to and from distant dispersal areas—especially critical when the rules of engagement for the air war relaxed in later years.
The gas-turbine-powered Mi-6, the Soviet Union’s first true heavy-lift helicopter, initially flew in September 1957 and entered production in 1961. Sturdily built, its transmission was actually heavier than its engines and could withstand tremendous punishment. The Mi-6 went into service in 1962 as the world’s largest and fastest helicopter and was unique at the time with its short, removable wings, which reduced the lift-load on the rotors during horizontal flight. It could transport up to 71 fully equipped infantry soldiers or 41 stretcher cases. Although it was rarely used to transport field artillery or mortars, the Hook’s cargo bay was large enough to carry any mortar then in the North Vietnamese inventory and any artillery piece except the M-46.
With its arrival in 1964, the Mi-6 Hook gave the NVAF a helicopter that was superior to any U.S. helicopter then in service. Its first operational missions began in mid-1965, and although Hanoi never employed the Hook in airmobile or air assault missions, it played a small but key role in North Vietnamese military operations.
With American fighters prohibited from shooting them down, Hooks became the transport of choice for high-priority, heavy-delivery requirements inside North Vietnam and eastern Laos, transporting SA-2 surface-to-air missiles, antiaircraft artillery and other heavy materials. They were critical to aircraft dispersal activities, conducting more than 400 lifts of MiG-17s alone during the war. They were also used for delivering critical supplies and equipment to Pathet Lao and NVA forces in Laos. The Hook soldiered on in Vietnamese service until well into the 1990s.