Operation Freedom Train
Operation Linebacker I

By late 1971, evidence that the North Vietnamese were planning an invasion became apparent to both military leaders and the Nixon administration. With only light ground action, limited troop contacts and the withdrawal of US ground troops continuing during the month, the level of air operations also remained low, a situation which continued generally throughout the first three months of 1972. During February 1972, naval air attack sorties in South Vietnam rose to 733 compared to eight during January. The increase was due to the preemptive operations by allied forces in preparation for an expected large-scale enemy offensive during Tet which did not materialize.

By the spring of 1972, North Vietnam had assembled a force of about 200,000 men, along with a substantial amount of ammunition and supplies, for a last attempt at invading the South. On 23 March 1972 the US canceled further peace negotiations in Paris because of a lack of progress in the talks. This was followed by the North Vietnamese invasion of South Vietnam. On March 29, 1972, enemy forces rolled directly across the demilitarized zone into South Vietnam while others penetrated via Laos. The South Vietnamese army, plagued by poor leadership and morale, was forced to retreat. This "Easter or Spring Offensive" was the result of the long buildup and infiltration of NVN forces during previous months and presaged some of the most intense fighting of the entire war.

President Nixon responded to this invasion with "Operation Freedom Train", which called for the renewal of general air strikes throughout North Vietnam above the 20th parallel for the first time since 1968. The North Vietnamese invasion prompted increased air operations by the carriers in support of South Vietnamese and US forces. The carriers on Yankee Station when North Vietnam invaded on 30 March were Hancock and Coral Sea. During the March four carriers had rotated on Yankee Station; they were Constellation, Kitty Hawk, Coral Sea and Hancock.

Operation Freedom Train involved Navy tactical air sorties against military and logistic targets in the southern part of North Vietnam which were involved in the invasion of SVN. The operating area in North Vietnam was initially limited to between 17th and 19th parallel. However, special strikes were authorized against targets above the l9th parallel on various occasions. The magnitude of the North Vietnam offensive indicated that an extended logistics network and increased resupply routes would be required to sustain ground operations by North Vietnam in their invasion of South Vietnam. Most target and geographical restrictions that were placed in effect since October 1968 concerning the bombing in North Vietnam were gradually lifted and the list of authorized targets expanded. Strikes in North Vietnam were against vehicle targets, lines of communication targets (roads, waterways, bridges, railroad bridges and railroad tracks), supply targets, air defense targets and industrial/power targets. Aircraft involved in Freedom Train operations were from Hancock, Coral Sea, Kitty Hawk and Constellation. By the end of April operations were permitted in North Vietnam throughout the region below the 20th parallel and many special strikes above the 20th parallel had also been authorized.

The aerial interdiction campaign against North Vietnam which began on 6 April 1972 with attacks in the southern part of the country expanded rapidly. Inclement weather along most bombing runs caused pilots to use precision instruments to destroy the targets during early April. However, once the weather cleared, visual strikes resumed, and the wing sent more and more aircraft into North Vietnam. The pilots on bombing runs were tasked to cut lines of communication and destroy transportation resources and surface-to-air missile sites.

On 16 April, B-52s, escorted by fighter and aircraft specializing in electronic countermeasures and suppression of surface-to-air missiles, bombed the fuel storage tanks at Haiphong, setting fires that, reflected from cloud and smoke, were visible from 110 miles away. Shortly afterward, carrier aircraft joined Air Force fighter-bombers in battering a tank farm and a warehouse complex on the outskirts of Hanoi. When these attacks failed to slow the offensive, naval aircraft began mining the harbors on 8 May, and two days later the administration extended the aerial interdiction campaign, formerly known as Freedom Train but now designated Linebacker, throughout all of North Vietnam.

On 13 May 1972 F-4Ds of the 8th Tactical Fighter Wing finally dropped the Thanh Hoa Bridge using guided bombs. Earlier attempts to destroy the bridge using dumb bombs, dating back to 3 April 1965, had consumed 873 sorties and cost 11 aircraft. On 18 May the scope of the air war in Vietnam changed when the Uong Bi electric power plant near Haiphong was struck. This marked the beginning of strikes on a class of targets formerly avoided, including power plants, shipyards and the Haiphong cement plant.

There was a dramatic change in North Vietnam's air defense effort during the summer months. During the earlier periods of April and May the Navy air effort involved intensive air-to-air combat and a large number of surface-to-air missile (SAM) firings. In contrast, during June and July there was an increase in Linebacker I Navy attack sorties but there was a decrease in the number of air-to-air combat incidents and SAM firings.

Scheduled for another Mediterranean cruise in July 1972, America instead found herself deploying one month early to Southeast Asia for a third time as a result of the Easter offensive by North Vietnam. CVW-8 would have aboard the new electronic counter-measure (ECM) EA-6B Prowler aircraft belonging to Tactical Electronic Warfare Squadron (VAQ) 132 for its first combat deployment. Combat operations commenced on 14 July in support of Republic of Vietnam troops in Military Regions One and Two. However a ruptured main feed pump on 24 July prompted America to return early to Subic Bay, Philippines for repairs. Combat operations resumed on 10 August in support of Operation Linebacker.

During the five and one-half month period of Linebacker I, the Navy contributed more than 60 percent of the total sorties in North Vietnam, with 60 percent of this effort in the "panhandle", two large regions between Hanoi and the DMZ. Tactical air operations were most intense during the July-September quarter with 12,865 naval sorties flown. Most attack sorties in North Vietnam fell into two classes--armed reconnaissance and strike. The former was usually directed against targets of opportunity with three main areas proscribed--near Hanoi, Haiphong and the Chinese border. Strike operations were preplanned and usually directed at fixed targets. Most types of fixed targets, not associated with armed reconnaissance, required approval by the Commander-in-Chief, Pacific, or by the Joint Chiefs of Staff, prior to attack. Principal Navy aircraft were the A-7 and A-6, which accounted for roughly 60 and 15 percent of the Navy's attack sorties, respectively. About 25 percent of the Navy's effort was at night. Carriers participating in the initial May-June operations from Yankee Station were Constellation, Coral Sea, Hancock, Kitty Hawk, Midway and Saratoga.

On 23 October 1972 the U.S. ended all tactical air sorties into North Vietnam above the 20th parallel and brought to a close Linebacker I operations. This gesture of good will in terminating the bombing above the 20th parallel was designed to help promote the peace negotiations being held in Paris. US tactical air sorties during Linebacker I operations helped to stem the flow of supplies into NVN, thereby, limiting the operating capabilities of North Vietnam's invading army.

In terms of tactics employed and results obtained, Linebacker was a vast improvement over Rolling Thunder. During Linebacker, American aircraft attacked targets like airfields, power plants, and radio stations which disrupted the flow of supplies and reinforcements to the units fighting in the South. Laser-guided bombs proved effective, especially against bridges, severing the bridge at Thanh Hoa, which had survived Rolling Thunder, and the highway and railroad bridges over the Red River at Hanoi. However, the enemy made use of alternate methods of crossing the streams, usually traveling at night on ferries or movable pontoon bridges. Electronic jamming as in Rolling Thunder confused the radars controlling the surface-to-air missiles and antiaircraft guns. North Vietnamese MiGs gave battle throughout Linebacker but they failed to gain control of the sky, in part because American radar detected enemy interceptors rising from runways, enabling controllers to direct Air Force F-4s and Navy fighters against them.

Nixon?s use of air power to disrupt supply lines and kill the enemy on the battlefield stopped the offensive and helped drive the enemy back a short distance without a reintroduction of the ground forces he had withdrawn from the South. In fact, the last combat troops of the U.S. Army departed in August 1972 while the South Vietnamese were counterattacking. Only 43,000 American airmen and support personnel remained. Yet the very success of the American aerial campaign caused misgivings in Saigon, where the South Vietnamese armed forces dependence on the Americans troubled President Thieu. When Thieu's commanders failed during a recent offensive, the advisers took over, bringing to bear a volume of firepower that the South Vietnamese forces themselves could not generate. Thieu realized the Americans' unilateral departure would leave South Vietnam at the mercy of the North Vietnamese forces still in his country. He balked at accepting what had come to be called a cease-fire in place, and the North Vietnamese also seemed uninterested in a settlement. President Nixon sought to remove first one and then the other obstacle to peace. He obtained Thieu?s reluctant assent to an in-place arrangement by offering "absolute assurance" that he intended to take "swift and severe retaliatory action" if North Vietnam should violate the terms of the agreement. He sought to remove the other roadblock, the stubborn attitude of the government in Hanoi, by ordering a resumption of the bombing of the heartland of North Vietnam.