Air Defenses

By the time of the Gulf of Tonkin incident in August 1964, the Hanoi regime’s antiaircraft defense system, was formidable and expanding rapidly. One of several American intelligence estimates in early 1965 indicated that North Vietnam possessed 1,039 antiaircraft guns: 322 14.5-mm and 37-mm, 709 57-mm, and eight 85-mm. There were an estimated 298 antiaircraft sites, of which 161 were considered active. The sites were located mainly around the Hanoi-Haiphong area and along important rail lines, roads, and bridges north and south of the two cities. US Air Force concern about the north’s antiaircraft defenses was pervasive.

Some 15,000 Soviet personnel served in Indo-China as advisers and occasionally as combatants. The largest part of the Soviet adviser personnel were air defense officers. The Soviets provided the aging V-75 (SA-2 GUIDELINE) missile system as the primary air defense system. They supplemented this with anti-aircraft guns and possibly some S-125 ‘Neva’(SA-3 GOA) missiles. Short-range air defense weapons included the Strela 2 (SA-7 GRAIL) shoulder-fired missiles.

The Soviet advisers primary mission was to train the North Vietnamese to use the Soviet equipment. The Soviets wore North Vietnamese uniforms while they performed their duties. The DRVN had a nation-wide integrated air-defense system with the bulk of assets in the north.

During the Vietnam War, North Vietnamese air defense radars targeted U.S. aircraft, which, in turn, countered with jamming and anti-radiation missiles. Due to the success of North Vietnamese air defenses, the United States was only able to establish temporary air superiority over local areas of North Vietnam. Over the course of the war, the North Vietnamese shot down 190 U.S. aircraft using 1950s-era Russian surface-to-air missiles (SAMs).

The Americans used a variety of specially equipped aircraft — such as F–100Fs, RB–66Bs, RB–66Cs, and EC–121Ds—to locate and/or neutralize the hundreds of enemy radar-controlled antiaircraft guns and Soviet-built SA–2 surface-to-air missile sites that appeared in the spring of 1965 around the north’s industrial areas, key logistic centers, and road and rail routes. American losses of aircraft, pilots and other aircrew mounted because of the ferocity of the north’s growing arsenal of antiaircraft guns, automatic weapons and SA–2 missiles, many of which could not be struck because of their proximity to the Hanoi-Haiphong area and the Chinese border.

SA-2 SAM deployments began in the Hanoi area, extending by the end of the year to Haiphong, the LOC area south of Thanh Hoa, and elsewhere. More than 60 sites were known by the end of the year. By the end of 1966, there were about 150 SAM sites in North Vietnam. Radar sites had grown to over 100, a mixture of early warning, ground-control intercept, AA fire control, and SAM-associated. Another 100 sites were discovered by the end of 1967, and the force organized into 25 SAM battalions. By April 1968, the North Vietnamese had 8000 AA weapons (the majority light AA or automatic weapons, but including 100mm AA guns) (The first of the 100mm AA guns were introduced in Jul 1965). There were more than 350 radars and almost 300 SAM sites.

The threats had a synergistic effect. The small arms and automatic weapons fire drove the aircraft out of the low altitude arena to higher altitudes where other AAA, SAMs, and enemy fighters were more effective. At the same time, the heavier AAA, SAMs, and fighters drove the aircraft back down to lower altitudes where those threats were less effective but the small arms fire was murderous. But the most effective North Vietnamese air defense had always been weather.

The air defense force was organized into divisions by Jun 1966.

• AA Division 361 formed 19 May 1965 for defense of Hanoi
• AA Division 363 formed Jun 1966 for defense of Haiphong
• AA Division 365 established Jun 1966
• AA Division 367 was a mobile unit established Jun 1966, and sent to MR 4 (initially with 4 AA gun and one AA missile regiments)
• AA Division 369 was established Jun 1966

Two further divisions were formed:

• AA Division 368 was established by 1968 in MR 4
• AA Division 377 was formed in MR 4 in 1968 with three regiments taken from other sites

Overall, the United States ultimately flew 299,054 sorties over North Vietnam, losing 609 aircraft in the process, a loss rate of 0.20% per 1,000 sorties. The North Vietnamese told a different story. SAM troops, which constituted the basis of the air defense of the DRV, had proven to be a formidable force in the struggle against piloted targets. From the date of their employment (24 June 1965) up to 15 May 1967 they nad downed 396 American aircraft; on the average three missiles were expended to destroy one target. Antiaircraft artillery and antiaircraft machine guns were the most numerous air defense means that the VPA has. They were credited with seventy-six percent of the American aircraft destroyed.

The Vietnamese information agency reported that, as of 15 May 1967, 1,900 American combat aircraft were destroyed over the DRV solely by the forces and means of the air defense and air forces of the Vietnam People's Army (VPA); thus, appreciable losses in equipment and pilots had been inflicted on the USAF. The number of aircraft claimed to have been downed comprised two percent of the overall total of aircraft sorties carried out by American aviation over the DRV. Aircraft losses by the end of World War II comprised one percent of the overall total of aircraft sorties carried out by their aviation during World War II.

PAVN strategy for the 1972 Nguyen Hue Offensive was significantly different from that of the 1968 Tet Offensive. In 1968 NVA / PLAF forces had tried to win over the population; this time, PAVN intended to attack population centers with armor and artillery. By March 1972 Hanoi had flooded the DMZ with anti-aircraft units, including surface-to-air missiles. This kept US air support at a distance while the NVA positioned armour, artillery and the 304 and 308 Divisions. Incredibly, many US and South Vietnamese intelligence analysts refused to recognize the signs of an imminent invasion. By the end of June 1972 the Easter Offensive had run out of steam.