Air Warfare in the Missile Age Page 3

  Surface-to-Air Missiles

  On 5 April 1965, photographs taken over North Vietnam by U.S. Air Force U-2 and Navy RF-8 reconnaissance aircraft confirmed what long had been anticipated: construction of surface-to-air missile (SAM) sites. Completing the third leg of North Vietnam’s integrated air-defense system, the Soviet-built S-75 Dvina surface-to-air missile system (NATO code-named SA-2 Guideline) extended the ground-based air-defense envelope around any target to a slant range of about twenty-four miles. American intelligence officers had been well aware of the effectiveness of the SA-2 ever since the loss of a U-2 over Russia piloted by Francis Gary Powers on 1 May 1960, and another over Cuba on 27 October 1962. Although the missile sites clearly represented a serious threat to U.S. aircraft, they were ruled off limits as targets because of the fear of killing Soviet technicians helping to build them and train the North Vietnamese in their use.29

  The SA-2 batteries launched a 35-foot-long missile that was guided to its target by radar control and detonated by a proximity fuse. A normal firing battery consisted of six launchers arranged around a central guidance radar. The SA-2’s guidance-control radar, NATO code-named Fan Song, was effective in guiding the missile against aircraft flying at altitudes between 3,000 and 60,000 feet.

  On 24 July 1965, the first American aircraft was lost to SA-2 surface-to-air missiles in Vietnam. Soviet and North Vietnamese personnel had positioned several SA-2 battalions in an area frequently overflown by American aircraft. A battalion commanded by Soviet Lt. Col. F. Ilinykh near the village of Chungha (some thirty-five miles northeast of Hanoi) opened fire and immediately shot down one U.S. Air Force F-4C. Additional missiles fired from this and other batteries damaged three other Phantoms.30

  The appearance of SA-2 necessitated a dramatic change in U.S. strike tactics. After the loss of the F-4C in July, strike aircraft attacking targets within the range of a missile site began flying at only several hundred feet above the ground, thus remaining below the 3,000-foot minimum effective altitude of the SA-2 missile system. Aircraft would pop up short of the target just long enough to acquire the target and release the bombs.

  A North Vietnamese S-75 Dvina (SA-2) surface-to-air missile site. Six missiles are arranged around a centrally located Fan Song guidance radar. The first American aircraft, a USAF F-4C, was lost to an SA-2 battery manned by both Soviet and North Vietnamese personnel north of Hanoi on 24 July 1965. Photo USAF.

  This temporary solution was less than ideal, because it placed the aircraft back within the range of the deadliest antiaircraft artillery. Nonetheless, zooming in at high speed and very low altitude and jinking gave the antiaircraft gunners the least amount of time to react and complicated their tracking solution.31 Meanwhile the United States embarked on a crash program to provide tactical aircraft with passive and active electronic equipment that could counter the threat of North Vietnamese SA-2 missiles, radar-directed antiaircraft artillery, and acquisition radars.

  In November 1965 the U.S. Air Force deployed specially modified F-100Fs to Korat RTAFB in Thailand. Labeled Wild Weasel I, the two-seat aircraft were equipped with sensitive radar homing and warning (RHAW) receivers. The RHAW gear allowed the Wild Weasel to detect the S-band Fan Song fire-control radar of the SA-2 missile and also to warn the pilot of the radar’s changes to the L-band guidance emissions when a missile was about to be fired.

  In addition the RHAW gear could detect and locate the S-band radar of antiaircraft guns and the S- and X-band radar of interceptor aircraft. This RHAW equipment was fitted to an increasing number of U.S. Air Force, Navy, and Marine Corps fighters and attack aircraft in a crash program.32

  With this RHAW gear, strike aircraft were able once again to penetrate missile-protected areas at more than 4,500 feet, putting them up out of range of the deadliest antiaircraft artillery but below the optimum altitude of the SA-2. With adequate warning from aircraft RHAW gear or indication from a EB-66C or EA-3B surveillance aircraft, pilots of the strike aircraft had a good chance at 4,500 to 15,000 feet of visually spotting a rising SA-2 missile and evading it by diving in a steep spiral. Once the Fan Song radar corrected the SA-2 missile for the aircraft’s diving maneuver, the aircraft would abruptly pull up, timing it so the missile would be unable to turn in time to remain locked on the plane. The missile’s speed would make it fly wide. Often, strikes received additional support from EB-66B, EF-10, and EA-1E jammer aircraft, which disrupted early-warning and SA-2 guidance radars.

  North Vietnam’s Air-Defense Network

  Early-warning radars and visual observers communicated their detection and track data on American aircraft to several regional command-and-control centers, which directed antiaircraft guns, surface- to air missiles, and MiG fighters to engage the attackers. The North Vietnamese employed manual command and control, and by late 1965 this system demonstrated the ability to employ antiaircraft guns, SA-2s, and MiGs in an integrated fashion. While antiaircraft artillery constituted the most effective element of the defense network, its effectiveness decreased with altitude. However, the potency of SA-2 surface-to-air missiles increased with altitude. MiG fighters posed a threat at any altitude and often enhanced the effectiveness of the other elements of the air-defense network by baiting U.S. fighters into surface-to-air missile traps or antiaircraft artillery “flak” traps,33 or by chasing off EB-66Bs with their updated jammers and Wild Weasels. By the end of 1965, the combination of elements in North Vietnam’s new air-defense network had downed eighty U.S. aircraft.34

  Rolling Thunder, 1965

  Between 12 and 17 May 1965, U.S. air strikes were suspended to allow American and North Vietnamese diplomats to negotiate. In less than a week, however, the talks broke down, and U.S. aircraft resumed bombing on 18 May. The renewed bombing, known as Rolling Thunder 18, included targets north of the 20th parallel, and the pace of attacks intensified to an average of 600 strike sorties per week.

  This image of an SA-2 missile in flight was caught by the camera of a reconnaissance aircraft over North Vietnam. Photo USAF.

  On 17 June 1965, U.S. Navy pilots downed their first North Vietnamese MiGs. F-4B Phantom II fighters from U.S. Navy Fighter Squadron 21 (VF-21) off the USS Midway shot down two VPAF MiG-17s with a pair of AIM-7 Sparrow air-to-air missiles in a head-on pass. This engagement was unusual because the radar-guided AIM-7 Sparrow was used—then the only missile that could be fired toward the target’s forward quarter as well as to the side or to the rear. U.S. rules of engagement in air combat over North Vietnam stated that a pilot could not simply fire at a target aircraft after picking it up on a radar scope, but must first visually identify it. By the time a pilot closed in enough to see the target aircraft, he was generally inside the Sparrow’s minimum range. At this point, if the target aircraft were approaching head-on, it was momentarily immune until the attacking pilot could maneuver to a new position to fire a heat-seeking Sidewinder missile toward the target’s hot engine in its rear quarter. U.S. Navy, Marine Corps, and Air Force F-4 Phantoms could not attack close-in targets since their missiles were ineffective at less than 2,000 feet and because they lacked a cannon.

  In the 17 June engagement, however, the F-4s radar allowed the crews—Comdr. Louis C. Page and his backseater, Lt. John C. Smith; and Lt. Jack E. D. Batson and his backseat radar-intercept officer—to set up for an AIM-7 shot before entering within range of the MiG-17s’ weapons. The key was that Commander Page was able to visually confirm the radar target as MiG-17s before they closed inside the minimum range of the AIM-7 Sparrow.

  As the U.S. air strikes against North Vietnam intensified (from 3 March to 1 November 1965, U.S. aircraft flew some 19,000 sorties against targets in North Vietnam), the number of MiG encounters increased to ten to fifteen per month. For the loss of three U.S. aircraft, American crews shot down five VPAF MiGs. The North Vietnamese admitted that the initial cadre of MiG-17 pilots had suffered serious losses in mid and late 1965 to American fighters, friendly antiaircraft fire, and operational accidents.35 However, new aircraft and VPAF pilots arriving from the Soviet Union brought North Vietnam’s MiG and pilot strength up toward the end of the year. Ground controllers and the surviving pilots were gaining in experience. Often MiG pilots flew ground-controlled intercepts only to break off before reaching an attack position. This pattern of standing down from combat to retain pilots and perhaps reevaluate tactics was to be repeated by the VPAF several times during the war.

  SAM Hunters: Wild Weasel, Shrike, and Iron Hand

  After the loss of the first F-4C to an SA-2 missile, the U.S. Joint Chiefs of Staff authorized strikes against several surface-to-air missile sites. On 27 July F-105s bombed two missile sites forty miles northwest of Hanoi. However, antiaircraft artillery shot down three aircraft, and two more were subsequently lost when one of the damaged aircraft collided with another as they returned to base.36 Rolling Thunder missions continued at a high tempo against North Vietnamese targets, including radar and missile sites, until the bombing halt on Christmas Day 1965 to allow diplomats to have another go at the negotiating table. The pause continued through 30 January, again with no diplomatic solution.

  The North Vietnamese made good use of the pause, repairing bomb damage to installations and expanding the coverage of antiaircraft guns and surface-to-air missiles. In the space of a month, the fledgling air-defense network grew considerably, with twenty-two new surface-to-air missile sites and more than 400 antiaircraft gun positions.

  Moreover, the North Vietnamese had far more prepared missile sites than SA-2 battalions, and the United States found it difficult to pinpoint the real batteries. As noted by Adm. U.S. Grant Sharp, “It soon became clear that the SAM sites were being moved around quite frequently, but we were forbidden to hit them until we had analyzed photographs of suspected sites.
By the time the photographs were analyzed, of course, the SAM sites had been moved elsewhere … and so the hunt was on again.”37

  The growth of the surface-to-air system began in the Hanoi area, taking advantage of the U.S. restriction against bombing within a thirty-mile radius of the city center. From there additional sites were constructed, covering the major railway links to China, which carried supplies from the Soviet Union and China. SA-2 sites were also sheltered within a ten-mile radius of Haiphong, airspace through which U.S. pilots were even prohibited to fly. Bombing missile sites and the targets they protected exacted a heavy toll on U.S. aircraft.

  After the Wild Weasels were deployed, one of these specialized jets was teamed with three F-105 fighter-bombers armed with conventional weapons. The four aircraft together, forming what became known as an Iron Hand flight, flew ahead of the main strike group to knock down North Vietnamese defenses. The Wild Weasels would seek out any radar emissions from SA-2 sites, and its F-105 escorts would release bombs and fire rockets to try to destroy the missile site before the main strike group arrived to attack the primary target. If the Iron Hand flight was successful, the main strike group was able to approach the target at medium altitude, free from the missile site’s threat and above the worst of the antiaircraft fire.

  The first four Wild Weasels were augmented by three more in February 1966. By that spring the U.S. Air Force had modified the F-100F Wild Weasel to carry the AGM-45 Shrike air-to-ground antiradiation missile (ARM) developed by the navy, in addition to 2.75-inch rockets and the internal 20mm cannon. When launched the Shrike missile homed on the SA-2’s Fan Song radar emissions.38 This gave the radar operator two options: shutting down or risking the site’s destruction. The cessation of the radar emissions, the source of guidance for the Shrike, would also cause the missile to go “dumb” and thus negate its chances of destroying the radar. The SA-2s could still be fired (and sometimes were) as a harassment tactic. Although it was preferable to destroy the radar site altogether, for short-term tactical purposes it was just as effective to suppress the radar by causing it to shut down.39

  Iron Hand SAM-suppression flights became standard for major strikes in North Vietnam. In addition to suppress antiaircraft-artillery flak the air force used its Wild Weasel aircraft in conjunction with F-105D or F-4 aircraft configured with bombs. The navy defense-suppression counterparts were A-4 or A-6 bombers, or F-4s—F-8 fighters equipped with Shrike missiles, bombs, and five-inch Zuni rockets.

  Later in 1966 both services introduced a specialized bomb that was especially effective against personnel manning antiaircraft-artillery sites. Known as a cluster-bomb unit (CBU), it consisted of many bomblets within a larger canister. After the canister was released, it split in half to scatter the bomblets in a large pattern sufficient to pepper an antiaircraft-artillery site with hundreds of live-explosive submunitions, like a rain of hand grenades. These made short work of any personnel not under cover.

  Flak-suppression flights would enter the target area first and drop their cluster bombs or other weapons on antiaircraft positions just as the strike aircraft started their bomb runs. If timed properly, the aircraft gunners would be suppressed (that is, forced under cover away from their guns) long enough for the strikers to complete their runs and escape.

  While the flak-suppression flights dueled with the antiaircraft gunners, the Iron Hand flights stood off, ready to greet any active SA-2 radar operators with a Shrike missile. As in tactics of SAM suppression—even though the artillery sites might not be physically destroyed—if the guns were shut down long enough to permit the strike aircraft safe passage to the prime target, the defense-suppression mission was considered a success.40

  Rolling Thunder Intensified, 1966

  The monsoon weather in February and March 1966 limited both ground and air activity. April saw gradual clearing of weather, and the secretary of defense authorized U.S. forces to fly 5,000 sorties per month and hit targets over the whole of North Vietnam, excluding only the Chinese border zone and restricted areas around Hanoi and Haiphong. For the first time, petroleum-oil-lubricant (POL) storage areas could be hit.41

  With improved weather in mid-April, aircraft from Kitty Hawk and Ticonderoga conducted extensive strikes. Railroad yards, water pumping stations, coal treatment plants, the Cam Pha power plant near the Chinese border, and the Uong Bi thermal power plant near Haiphong were all struck in rapid succession.42

  As new targets were authorized, a new target-assignment system was developed. The U.S. Air Force and the Navy divided North Vietnam into six target areas, or route packages. Previously the services rotated where strikes would take place to alternate their pilots’ exposure to more and less dangerous areas. Now the U.S. Air Force took the western and Hanoi route packages closer to its Thai and South Vietnam bases, while the navy took the Haiphong and coastal route packages near its aircraft carriers.

  With this new system, the area in which each service assigned targets was halved, allowing crews to become more familiar with the terrain and the defenses.43 The new division resulted in a telling improvement in losses. Once familiar with an area, crews could plan better attack routes to minimize exposure to enemy defenses. During the monsoon season, until 1966, many navy strikes were canceled in the northern route packages, allowing the North Vietnamese to move freely under cloud cover. The air force was able to fly despite bad weather because its Skyspot radar bombing system allowed F-105s to hit targets via radar bombing. A ground radar station, Lima Site 85 in Laos, tracked the aircraft and signaled when to drop their bombs. After July 1965 the navy introduced its A-6 Intruder all-weather bomber, with a radar system sophisticated enough to allow its crews to operate in bad weather and at night.

  The Second Phase of the Battle for Air Superiority

  After the infrequent engagements in the first five months of 1966, the almost daily U.S. Air Force and Navy strikes against targets in route packages IV, V, and VI brought U.S. aircraft within the operational radius of the MiGs. Subsequently, engagements with MiGs rose sharply. From an average often or fewer engagements per month, the rate jumped to twenty-five by April 1966. On 14 March VPAF pilot Nguyen Hong Nhi reportedly downed a Firebee drone for the MiG-21’s first kill, and on 23 April U.S. crews had to defend against a gun attack by a MiG-21.44 A flight of U.S. Air Force F-4Cs from the 555th Tactical Fighter Squadron, Eighth Tactical Fighter Wing, which was providing escort for an F-105 strike against the Bac Giang Bridge, about twenty-five miles northeast of Hanoi, shot down the first MiG of 1966 on the same day. The USAF Phantom crews detected MiG-17s approaching head-on, confirmed their identity, and fired Sparrows but with no hits. A swirling dogfight ensued, and both sides traded fire, the MiG-17s employing cannon, and the F-4s missiles. It was the Phantoms’ missiles, however, that finally struck home, destroying two MiG-17s.

  Most American aircraft lost over Vietnam fell to antiaircraft fire. This USAF F-105D is flying through a flack barrage after attacking its target. The aircraft has dropped its weapons and is carrying two ECM pods, which could jam radars directing SA-2 SAMs and antiaircraft guns. Photo USAF.

  Three days later VPAF MiG-21s were vectored in and made an attempt to shoot down a high-value USAF EB-66. The F-4C fighter escort engaged the MiG-21s, and Maj. Paul Gilmore and Lt. William Smith destroyed one of the MiG-21s after several attacks with Sidewinders. This was the first MiG-21 destroyed in the Vietnam War. During the next several weeks, U.S. Air Force F-4Cs also scored several victories against MiG-17s for the loss of a single A-1E, downed by a MiG-17.45 The navy drew its first blood of 1966 on 12 June, when F-8E Crusader fighters escorting A-4 Skyhawk bombers tangled with four MiG-17s north of Haiphong. Comdr. Harold L. Marr, commanding officer of VF-211, downed one of the MiGs with an AIM-9 Sidewinder air-to-air missile at an altitude of fifty feet and damaged another with cannon fire that later crashed.