Surface-to-Air Missiles (SAMs)
On 17 November 1964, the Soviet Politburo decided to send increased support to North Vietnam. The largest part of the Soviet adviser personnel were air defense officers. The Soviets provided the 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 defenseweapons 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.
The SA-2 system was first fielded in 1957 and was a fairly obsolete and cumbersome system by 1972 standards. USAF loss rates during Operation Linebacker II were considerably below their loss rates during World War II strategic bombing missions. USAF and USN electronic countermeasures seriously degraded the performance of the SA-2 system during Operation Linebacker II.
The first North Vietnamese SA-2 surface-to-air missile (SAM) site did not begin construction until April 1965. However, by the end of Rolling Thunder in October 1968, the DRV had seventy-five hundred antiaircraft guns; and two hundred SAM (SA-2) sites. Construction of SAM sites in North Vietnam seemed strangely protracted. The delay apparently was caused by a dispute over who was to man the SAM sites and over the transit of Soviet SAM and other military personnel through China. A number of authoritative Chinese sources indicate that in early March 1965 (presumably in accordance with the understandings Kosygin had reached with the Vietnamese in Hanoi in February) the Soviets proposed to send to the DRV by rail through China eight battalions of SAMs and four thousand Soviet advisors and technicians. The Chinese strongly objected. It was reported that the North Vietnamese had refused to permit the Soviets to man the rockets being installed in order to avoid "alienating" the Chinese.
Construction of the first SAM site near Hanoi -- apparently begun at the end of March 1965, and discovered in photography on 05 April 1965 -- proceeded at a very leisurely paae. A month later, in early May 1965, the launch revetments at this first site were nearing completion, and a second site waa begun; but no SAM hardware had been installed. After another two months had gone by, late in June, there were still only four sites under construction, three of which were nearing completion (including the one begun in late March) and one of which waa half-complete. Only one site at this point had yet been even partially supplied with missile-associated equipment.
All in all, the evidence suggests that throughout the spring of 1965 the DRV vacillated between yielding to Chinese pressure and thus deferring completion and activization of SAM sites until the fall, when North Vietnamese cadres could complete their training in the USSR to operate them, or flouting Chinese wishes and accepting enough Soviet personnel to put the SAMs into operation more promptly. Finally, under the influenceof the mounting US bombing, the DRV seems to have opted for the latter course, and prevailed upon Peking to permit a limited quota of Soviet SAM personnel to pass.
The bulk of Soviet SAM equipment and personnel, following a Chinese agreement to let specific numbers pass at the beginning of June,arrived by stages in North Vietnam in the latter half of June and the first half of July, and thus coincided roughly with the increase in U.S. air strikes against DRV territory north of Hanoi. North Vietnamese propaganda displayed greatly increased concern about this US movement northward, and seemed particularly exercised at the violations of Hanoi's "suburban airspace" and the attacks on one of the rail lines to China.
The Chinese in mid-July 1965 suddenly issued a flurry of private and public statements calculated to exploit Vietnamese anxiety and to create pressures upon the USSR to commit the newly-arrived Soviet SAM equipment and personnel to action at once against the United States. On 14 July, the CCP finally answered the CPSU letter of17 April dispatched after Le Duan's visit to Moscow; among other things, the Chinese defended themselves at length (although rather lamely) against the charge that they had obstructed Soviet aid to Vietnam, and then went on to sneer again at "the quantity and quality of your aid" as having been "far out of proportion to the power of your country," and, in fact, "old, out-moded, impractical and inferior." This was despite the fact that Vice Premier Lu Ting-i had criticized the Soviet "adventurism" in bringing the missiles to Vietnam in the first place.
It was not until 24 July 1965 that the SAMs were fired for the first time, by Soviet crews. And on 27 July the first US attempt to destroy SAM installations was made. On 28 July, the Chinese made their first comments: a Japanese newspaper quoted "a reliable source close the Chinese Government" as emphasizing that "the so-called missile bases... are likely not as large as is generally stated, nor have they yet been completed." Commenting on the US strike at the SAM bases, the Chinese source remarked: "The US has been emphasiting that there is no 'sanctuary' from the US air strikes, so it seems rather strange that the US has not made them bombing targets before now."
The Soviets, meanwhile, while continuing through-out the summer and fall of 1965 to expand their presence in the DRV and to multiply the number of alternative, unoccupied SAM sites, took steps to limit the risk of confrontation with the United States deriving from the activities of Soviet personnel in Vietnam. Soviet propaganda, while making occasional generalized claims to the effect that the USSR had furnished weapons and military equipment to North Vietnam, carefully avoided direct public acknowledgement that any Soviet military personnel were in the DRV or even that the Soviet Union had sent surface-to-air missiles to North Vietnam.
The SA-2 was numerous as well as deadly. After launch the missile accelerated to Mach 3.5 and had a maximum range of about 25 miles. It could intercept targets flying as high as 50,000 feet, but was generally ineffective against aircraft flying at high speeds at altitudes under 3000 ft. The number of sites would increase dramatically, from 9 in late summer 1965 to over 25 by early December 1965. Between 22 and 24 SA-2 systems were operational during the Wild Weasel I test period in late 1965.
When SAM subunits first appeared in the air defense of the VPA, they too were committed initially for action from "ambushes." In order to avoid enemy air strikes (American aviation, upon detecting SAM subunits, strove to destroy them by strafing and bombing), SAM battalions changed launching sites after every firing, executing marches of varying distances by their own means. Moves to new launching sites were executed under night conditions. The total time spent in moving from one site to another over a distance of thirty to forty kilometers was ten to fifteen hours. A battalion would spend 2.5 hours to pack-up its equipment and 3 hours to set it up. In addition, approximately v/ 2 to 2.5 hours were devoted to checking and adjusting the equipment.
Moves were also made by radiotechnical troops in order to assure the viability of the radar coverage and equipment. Alternate positions for radar companies were selected at distances up to fifteen to twenty kilometers from the primary ones. The move by radar companies to alternate positions was accomplished during a single night.
With the rise in the number of bombing and strafing strikes against SAM battalion launching sites, especially after American aviation changed over to low altitude actions, three to five small-caliber antiaircraft artillery batteries and three or four antiaircraft machine-gun platoons began to be allocated to each launching site to provide cover. Furthermore, toward the end of 1965, to provide cover for individual installations, anti-aircraft artillery and machine-gun units and subunits began to be employed jointly with SAM battalions, thereby significantly enhancing the effectiveness of the defense of installations. But nevertheless the matter of defending SAM systems against air strikes was not fully solved.
Therefore, in addition to aggressive defense measures, widespread use was made of camouflage by the subunits themselves utilizing materials available at hand. To this end, the positions formerly occupied were often converted into dummy positions by setting up dummy launchers and radars and with imitation missile launches (powder charge bursts with an admixture of brick dust). As a result of the measures taken, combat equipment and personnel were preserved and, furthermore, a considerable number of American aircraft were destroyed, despite the limited number of SAM battalions in the VPA air defense. As a result of the measures taken, combat equipment and personnel were preserved and, furthermore, a considerable number of American aircraft were destroyed, despite the limited number of SAM battalions in the VPA air defense.
Taking into account the experience of combat with US aviation and the recommendations of our military specialists, the VPA command reviewed the movement tactics of the SAM troops. The need for this review became particularly evident because Hanoi, the DRV capital, and Haiphong, the principal seaport, were not, when needed, protected by SAM troops, since the SAM battalions had moved to new launching sites in advance of American air raids on the suburbs of these cities. As a result of the air strikes, supply dumps with large fuel supplies, located in the suburbs, were destroyed.
In light of this, since July 1966 an installation-zonal SAM defense was established in the area of the Hanoi-Haiphong cities. SAM battalions formed a solid SAM zone cover for this area. In addition, the defense has been strengthened by a large number of tube antiaircraft means, and all fighter aviation of the VPA air forces has been located within the zone. Thus the bulk of available active air defense means, capable of destroying simultaneously several tens of targets, were concentrated in the Hanoi-Haiphong area.
The SA-7s forced changes in strike and aircraft tactics. Most of the low performing aircraft were forced out of the area and close air support was conducted by the high performance fighters. VNAF airlift could not handle the task. Since An Loc was completely encircled, it had to be totally supported by airlift. SA- 7 s and AAA forced helicopters and C-123s out of the battle area. Initial attempts to operate C-130s with container delivery drops were costly. Three C-130s were lost and new high altitude drop techniques were initiated that made it possible to support An Loc until the siege was broken.
On 14 December 1973, President Nixon ordered a new bombing campaign to begin against North Vietnam. Linebacker II began on 18 December 1972. This time B-52s were used in air attacks on Hanoi and Haiphong. Despite unexpectedly heavy B-52 losses, the attacks were extended beyond the originally planned three days. Linebacker II destroyed most of the legitimate targets in North Vietnam and added a new target: the North Vietnamese air defense system. By 27 December 1972, North Vietnam was virtually defenseless and began arrangements for new peace talks. On 29 December 1972, President Nixon ordered a halt to the bombing of North Vietnam, ending Linebacker II.
During the course of the air war over North Vietnam there had been a steady drop in the effectiveness of the SA-2 missile, as the various countermeasures took effect. The US command, on the basis of a detailed analysis of reconnaissance data and the study and exposure of the weak aspects of the SAM systems employed in the DRV, developed for its aviation new tactical approaches to overcome SAM defenses. The basic one was the following evasive action: after detecting a missile launch from an altitude of 1.5 to 2 kilometers, the aircraft dives sharply to an altitude of 400 to 300 meters, changes its flight bearing 90 to 180 degrees, and leaves the kill zone of the missile system. In addition to this, there is widespread use of very intensive combined jamming (active and passive simultaneously), which, as a rule, prevents accurate missile launches. There was also an increase in the number of air strikes with Shrike type guided missiles against SAM battalion launching sites.
A reduction in firing results was also caused by deficiencies in the combat use of SAM troops. Since 1966 Vietnamese crews had been conducting combat firings independently, not having had enough practice with and knowledge of the equipment from the very beginning. There were even cases when missiles were launched without preparing initial data and without checking the technical equipment. Such missile launches were called the accomplishment of a tactical task to scare off American aircraft. The requirements of Firing Regulations were often not fulfilled: in firing against a maneuvering target, instead of a salvo of three missiles, a single missile was launched. When tracking a target manually, laying operators made errors in angle of sight, as a result of which the missiles went far off the target.
When it was first used on a large scale, in 1965, the SA-2 destroyed about ten fighter-bombers for an estimated 150 Guidelines launched: an average of one kill for every fifteen missiles. By November 1968 one aircraft was being shot down for every 48 missiles fired. During Linebacker II one aircraft was destroyed for roughly every 50 Guidelines fired.
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