Arguably, the relief of Khe Sanh was the war’s most important cavalry raid.
One of the great battlefield innovations developed by the United States armed forces in its effort to defeat a skilled and often elusive enemy in Vietnam was air cavalry—light infantry deployed by helicopters. While swift-moving aircraft supplanted horse or mechanized ground transport, the theory of rapid deployment of light infantry remained the same. The infantry’s mission is to close with the enemy by means of fire and maneuver to defeat or capture him, or to repel his assault by fire, close combat and counterattack. Only close combat between ground forces gains the decision in battle. Whether on foot, horse or vehicle, parachuting from an aircraft, or jumping from a helicopter, the infantry must maneuver as part of its mission. At all levels of war, successful maneuver requires agility of thought, plans, operations and organizations.
At the operational level, maneuver is the means by which the commander determines where and when to fight by setting the terms of battle, declining battle, or acting to take advantage of tactical actions.
As a concept, air cavalry was innovative. As executed by air cavalry units, it was phenomenal, and the 1st Cavalry Division in Vietnam was the quintessential air cavalry organization. Its prominent and evolving role began in the Ia Drang Valley in 1965, and one of its greatest achievements came at Khe Sanh in 1968.
Air Cavalry Concept Takes Flight
On June 15, 1965, Defense Secretary Robert McNamara approved the incorporation of an airmobile division into the Army force structure with the designation 1st Cavalry Division (Airmobile). The first “air cavalry” division was well trained and equipped when it arrived in Vietnam in August and September 1965. Its official mission was to provide reconnaissance for larger field force commands, participate in stability operations and provide security and control over the population and resources in its assigned area. While airmobile operations used helicopters to fly over difficult terrain and maneuver behind enemy defenses to air assault into targeted objectives, the 1st Air Cav, as it was often called, excelled in the traditional cavalry missions to reconnoiter, screen, delay and conduct raids over wide terrain.
The 1st Cavalry Division (Airmobile) was an organization of about 15,000 men. It had its own infantry, artillery, logistics and other division support capabilities; but most important, it had its own aviation assets assigned to the division to provide aerial reconnaissance, troop transport, aerial rocket artillery fire support and logistical transport. It integrated attack, transport and observation aircraft with the fighting elements of the division.
The “combat air assault” was the zenith of the attack phase of air mobility. A combat air assault, as a tactical mission, was more than merely transporting troops from point A to point B by helicopters. Once the enemy was located and contact was made, air cavalry troops could be swiftly deployed by helicopters from less critical situations and concentrated at the point of battle.
The combat air assault was usually conducted by a company commander (a captain) or platoon leader (a lieutenant), with an order to go from one point to another for a particular mission: recon, screen, delay, raid or search and destroy. Huey lift flights, usually four to six helicopters, picked up the cavalry troopers and transported them to the mission’s landing zone. As the Hueys approached, artillery pounded the landing zone, ending with a white phosphorus round impact that let the helicopter pilots know to start their descent. First, Huey or Cobra gunships would strafe the LZ with suppressing fires in case enemy troops planned an ambush before the lift ships landed, and then troopers would dismount to continue their mission.
Radio communications enabled commanders, often in command and control helicopters, to monitor scout ship transmissions and to direct responsive air landings in the midst of fluid combat situations. As the infantrymen deployed from the helicopters with rifles and machine guns blazing, gunships patrolled overhead providing close-in covering fire with rockets and machine guns. Rapid helicopter airlift of howitzers and ordnance assured that infantry fighting for remote and isolated landing zones would have sustained artillery fire support. Enemy opposition was often stunned and overwhelmed by this quickly executed initial aerial onslaught.
The maneuverability of the 1st Air Cav was made possible by the helicopters assigned directly to the division. Hueys provided most of the unit’s helicopter transport and gunship capability. They transported food, water, ammunition and personnel, and medevaced the wounded and dead. Prior to the introduction of Cobra AH-1 gunships, Hueys were fitted with machine guns, Gatling guns and 2.75-inch rocket pods. These gunships provided aerial rocket artillery for the infantry. When Cobras replaced Hueys as gunships, they often operated with OH-6 light observation helicopters (LOHs) in “hunter-killer” teams to search and destroy the enemy.
The Air Cavalry also depended on the twin-rotor CH-47 Chinook to airlift its essential artillery and heavier supplies to support the sky troopers wherever they went. The Chinooks could carry either 44 troops or 10,000 pounds of cargo.
Into the Valley
The air cavalry concept was first tested in the fall of 1965 in the Ia Drang Valley against North Vietnamese Army (NVA) regulars. The campaign that began on October 27, 1965, saw a month of sustained action in which the 1st Cav sought out, located and met the NVA in combat and won some of the fiercest battles of the entire war. Helicopter-delivered infantry dominated the zone of operations, validating the revolutionary role of aerial cavalry and setting the pace of future wartime air mobility. The 34-day Ia Drang Valley campaign was the first division-scale air assault victory.
Although the division could helicopter troops throughout the battle zone—regardless of terrain restrictions—faster than any other organization in the Army and decisively engage distant enemy units by vertical air assault, this flexible striking power required thorough preparation and sufficient reserves.
While the Army’s AirLand Battle doctrine was developed after the Vietnam War and the demise of the Air Cavalry, the Air Cav’s unique capabilities and organization in the Ia Drang campaign nonetheless displayed and proved the importance of the doctrine’s tenets of initiative, agility, depth and synchronization, as Lt. Col. Kenneth R. Pierce of the U.S. Army Command and General Staff College describes in a 1989 analysis of the campaign in Military Review:
Initiative. Major General Harry Kinnard, commander of the 1st Cavalry, intended to set the terms of the battle. He was on the offensive and felt he could find the enemy forces and that he had the mobility and firepower to fix and destroy them. He was taking great risk and knew that the unit that made initial contact would be seriously outnumbered, but believed he could reinforce with fire almost immediately and then pile on troops before the enemy could react.
Agility. The helicopter gave Kinnard the ability to act faster than the enemy. He shifted forces and combat power at unprecedented speed and put field artillery and aerial rocket artillery with great accuracy anywhere on almost a moment’s notice. He reinforced with troops faster than anyone ever in the history of warfare. With excellent communication capability and troops trained in calling in for air, mortar or artillery fire support, he could quickly concentrate on the battered enemy and exploit his vulnerabilities. Cavalry tactics take into account the accumulation of chance errors, unexpected difficulties and the confusion of battle, and Kinnard, by nature, disposition and training, knew that he had to continuously “read the battlefield,” decide quickly and act without hesitation.
Depth. The helicopter and the cavalry’s training in its use naturally extended operations in space, time and resources. The helicopter gave Kinnard a greater range of vision for reconnaissance, allowed him to provide accurate aerial rocket artillery, adjust fire from the air, reposition his field artillery, resupply his troops and reinforce with maneuver forces almost anywhere on the battlefield. His rear areas were relatively safe, but he still provided an infantry battalion to secure his artillery and his forward command post. He had airstrips built so that the Air Force could resupply his base at An Khe from Saigon, and he maintained enough helicopter lift to move those supplies to the frontline troops. He was mentally prepared for bold and decisive action, and he had personally trained his handpicked brigade and battalion commanders with these same qualities.
Synchronization. Two years of training together with all the modern technology had taught the cavalry how to arrange activities in time, space and purpose. Kinnard possessed the forces and combat power to produce maximum results at the decisive point. Their training and communications capability allowed synchronization even during heavy conflict without explicit coordination. The concept of searching with a battalion and piling on brigade and supporting units at the decisive time and place using the entire division, field force and Army fire support, was an economy-of-force type operation.
Despite some significant problems and high cost, the 1st Cavalry’s Ia Drang Valley campaign prevented an NVA victory over the Special Forces Camp at Plei Me, and the lessons learned proved valuable in subsequent airmobile operations after Ia Drang. Notable among them were the 1966 coastal campaign of “sustained pursuit” (offensive action against a retreating enemy) and the 1967 coastal campaign of “clearing operations” (finding and destroying the enemy and implementing pacification programs). The Air Cav also protected Saigon using a “cavalry screen,” executed “cavalry raids” at Khe Sanh and in the A Shau Valley and “cavalry exploitation” in the Cambodia invasion.
The Pegasus Pirouette
The Communists’ primary objective in the 1968 Tet Offensive was to seize power in South Vietnam and cause the defection of major elements of the Vietnamese armed forces. General William Westmoreland stated, “There is also little doubt that the enemy hoped at Khe Sanh to obtain a climacteric victory such as he had done in 1954 at Dien Bien Phu in the expectation that this would produce a psychological shock and erode American morale.”
Khe Sanh was 15 miles south of the Demilitarized Zone (DMZ) and about seven miles from the eastern frontier of Laos. The Khe Sanh base functioned primarily as a support facility for surveillance units watching the DMZ and probing the outer reaches of the Ho Chi Minh Trail in Laos. To the south, Khe Sanh overlooked Highway 9, the only east-west road in the northern province connecting Laos and the coastal regions. A key feature at Khe Sanh was its 3,900-foot aluminum mat runway that—during favorable weather conditions—could accommodate fixed-wing aircraft, including C-130 transports.
In the first weeks of 1968, signs of an impending enemy attack at Khe Sanh mounted and as many as four North Vietnamese divisions were identified just north of the DMZ. There were also indications that the enemy was moving up several batteries of artillery in the southern half of the DMZ as well as in areas close to the Laos border—all well within range of the Khe Sanh Combat Base.
Convinced that the North Vietnamese would strike a massive blow on Khe Sanh, the American command swiftly moved to strengthen its forces in the area. The combat base was reinforced, bringing the troop level to a little less than 6,000. Concurrent with the buildup of the allied forces in the vicinity of the DMZ, B-52s began to systematically pattern bomb suspected enemy locations near Khe Sanh and tactical fighter-bombers stepped up attacks in North Vietnam’s southern panhandle. East of Khe Sanh, U.S. Army heavy artillery was assembled at the Rock Pile and Camp Carroll to provide quick reaction long-range fire support to the Khe Sanh base.
In the early hours of Jan. 21, 1968, the enemy attacked Khe Sanh with withering artillery, rocket and mortar fire, and probed outlying defensive positions to the north and northwest. South of the base the North Vietnamese attempted to overrun the villages of Khe Sanh and Huong Hoa but were beaten back by Marine and South Vietnamese defenders. In this initial action, enemy fire destroyed virtually all of the base ammunition stock and a substantial portion of the fuel supplies. The all-important airstrip was severely damaged, forcing a temporary suspension of flights into the area.
For the next two months, worldwide attention was riveted on Khe Sanh, where the North Vietnamese seemed to be challenging the United States to a set-piece battle on a scale not attempted since the great Communist victory at Dien Bien Phu.
The 1st Air Cavalry was the logical unit to relieve the beleaguered Marines at Khe Sanh, and the Air Cav commander, Maj. Gen. John J. Tolson, was tasked with defining and executing Operation Pegasus, which had a threefold mission: relieve the Khe Sanh Combat Base, open Highway 9 from Ca Lu to Khe Sanh and destroy the enemy forces within the area of operation.
Although Marines and Army of the Republic of Vietnam (ARVN) forces augmented the 1st Cavalry, it was the operational planning and maneuverability of the air cavalry that dominated the execution of Pegasus. Tolson’s planning drew from the lessons the division learned in previous successes, starting with Ia Drang. Tolson described the basic concept of Operation Pegasus in Airmobility, 1961-1971:
The 3d Brigade would lead the 1st Cavalry air assault…the 2d Brigade of the Cavalry would land three battalions southeast of Khe Sanh and attack northwest and the 1st Brigade would air assault just south of Khe Sanh and attack north….The 3d Army of the Republic of Vietnam Airborne Task Force would air assault southwest of Khe Sanh and attack toward Lang Vei Special Forces Camp. Linkup was planned at the end of seven days.
Airmobility was the first key to the planning and execution of Operation Pegasus, providing the capability for initiative, agility, depth and synchronization. Tolson constructed an airstrip known as Landing Zone Stud in the vicinity of Ca Lu that would be critical to the entire operation. He also upgraded Highway 9 between the Rock Pile and Ca Lu to allow stocking of supplies at LZ Stud, establishing a forward base there. The second key element to success was the closely integrated reconnaissance and fire support effort of the 1st Squadron, 9th Cavalry. Initial surveillance showed that the enemy had established positions designed to delay or stop any attempt to reinforce or relieve Khe Sanh. As part of the reconnaissance by fire, known or suspected enemy antiaircraft positions and troop concentrations were sought out and destroyed, either by organic fire or tactical air. “The thoroughness of the battlefield preparation was demonstrated during the initial assaults of the 1st Cavalry Division,” wrote Tolson, “for no aircraft were lost due to antiaircraft fire or enemy artillery.”
Tolson detailed the ballet-like air cav operation:
At 0700 on 1 April 1968 the attack phase of Operation Pegasus began….At the same time, the 3d Brigade of the 1st Cavalry was airlifted by Chinooks and Hueys into landing zone Stud in preparation for an air assault into two objective areas further west. Weather delayed the attack until 1300, when the 1st Battalion, 7th Cavalry, air assaulted into landing zone Mike located on prominent ground south of Highway Nine and well forward of the Marine attack. The 2nd Battalion, 7th Cavalry, went into the same landing zone to expand and develop the position. The 5th Battalion, 7th Cavalry, air assaulted into an area north of Highway Nine….
On D+4 (5 April), the 2d Brigade continued its attack on the old French fort meeting heavy enemy resistance….Units of the 1st Brigade entered the operation with the 1st Battalion, 8th Cavalry, air assaulting into landing zone Snapper, due south of Khe Sanh and overlooking Highway Nine….The heaviest contact on that date occurred in the 3d Brigade’s area of operation as the 2d Battalion, 7th Cavalry, continued its drive west on Highway Nine….The troops of the 1st Cavalry Division were airlifted to Hill 471 relieving the Marines at this position….At 0800 on 8 April the relief of Khe Sanh was effected and the 1st Cavalry Division became the new landlord. The 3d Brigade airlifted its command post into Khe Sanh and assumed the mission of securing the area. This was accomplished after the 2d Battalion, 7th Cavalry, successfully cleared Highway Nine to the base and effected linkup with the 26th Marine Regiment….At this time it became increasingly evident, through lack of contact and the large amounts of new equipment being found indiscriminately abandoned on the battlefield, that the enemy had fled the area rather than face certain defeat. He was totally confused by the swift, bold, many-pronged attacks.
Further significance of Pegasus was the interservice integration. Tolson praised “the great team effort of all the services, Army, Navy, Marines and Air Force….The fact that we were able to co-ordinate all of these operations in a single headquarters was a commander’s dream.” However, interservice rivalry also existed and some in the Marine Corps adamantly claimed that Khe Sanh was never under siege as it could be resupplied by airdrops. Some Marines contended that the Air Cavalry relief was unnecessary as they fought their way out of the siege.
The 1st Cavalry Division’s end of the 77-day siege at Khe Sanh in just eight days was a testament to air cavalry tactics and dramatically illustrated the speed and effectiveness with which a large force can be employed in combat. The enemy’s repeated failure to quickly comprehend the reaction time and capabilities of the Air Cav led to his defeat. Arguably, the relief of Khe Sanh was the war’s most important cavalry raid—a rapid attack into enemy territory to carry out a specific mission without the intention of holding terrain and then promptly withdrawing when the mission is accomplished.
New Threats, New Cav
After Vietnam, the perceived military threat to the United States was the Soviet army’s armored and mechanized divisions in Europe. That led the Army to reorganize the 1st Cavalry as a “triple capability” (TRICAP) division in 1971, combining armor, airmobile and air cavalry brigades. The post-Vietnam era saw curtailed airmobile capabilities—reflected in the 1976 edition of the Army Field Manual 100-5, Operations, and the concept of “active defense.” This doctrine, wrote Robert Hamilton of the School of Advanced Airpower Studies, had focused “airpower thinking on close air support and anti-armor roles to the detriment of more flexible and independent applications.” Major Kevin J. Dougherty, serving as chief of the Current Analysis Division, Intelligence Directorate, at U.S. European Command, wrote in Joint Force Quarterly in 1999 that “the TRICAP experiment became mired in bureaucratic ineptitude and, by August 1980, the 1st Cavalry was transformed into a heavy armored division.”
In October 1974, the 101st Airborne Division dropped the parenthetical Airmobile in favor of Air Assault and accepted the implied doctrinal change, which attempted to fuse manpower, weapons and aerial transport with “cavalry doctrine.” Although the 101st took the title Air Assault, it does not conduct “air assaults” or other air cavalry tactics, which integrate attack, transport and observation aircraft with the fighting elements of the division, as did the 1st Air Cav. The 101st Air Assault Division ensures continuous availability of aviation assets to meet unique tactical requirements, but it is not an air cavalry division. A “combat air assault” is an air cavalry tactic—not merely an airmobile transport of troops by helicopter.
Another contributor to the demise of “air cavalry” tactics was the advent of a separate Army Aviation branch in 1983 and the development of the Apache helicopter, which could “stand off” at some distance and engage targets. Gone was the tactic of close-in fire support for the dismounted sky troopers from an attack helicopter such as a Cobra. This aviation independence and the Army’s new tactics effectively ended the synchronized combat air assault that was the hallmark of the 1st Air Cavalry Division.
An Air Cav for the 21st Century?
Dougherty wrote in 1999 that some Army thinkers recognized that “the integration of infantry mobility and target acquisition capability with the speed, agility, and firepower of helicopters is a potent combination; but the current force structure does not capture the helicopter’s air cavalry possibilities.” Noting that helicopter modernization programs make a genuine air cavalry role a promising prospect for incorporation into all divisions, Doughtery concluded, “Doctrine and tactics built around an organization of air assault deployable light infantry and air cavalry brigades would be more in line with a true revolution in military affairs.”
The future military will be smaller, more technologically oriented and have swift-moving forces to perform its missions. As then-Defense Secretary Robert Gates said in 2011, “The strategic rationale for swift-moving expeditionary forces, be they Army or Marines, airborne infantry or special operations, is self-evident given the likelihood of counterterrorism, rapid reaction, disaster response, or stability or security force assistance missions.” President Barack Obama announced in early 2012 that the military will be reshaped over time with an emphasis on countering terrorism, maintaining a nuclear deterrent, protecting the U.S. homeland and “deterring and defeating aggression by any potential adversary.”
While air cavalry tactics can be executed by Army Rangers, Navy SEALs or Marine or Air Force special operations forces, such as in the 2011 raid that killed Osama bin Laden, future military planning should create true air cavalry units, such as the Vietnam-era 1st Cavalry Division, composed of specially trained and equipped personnel—not out of nostalgia, but out of a sense of what is most mission-oriented and best for America’s national security interests.
Colonel Joseph E. Abodeely, USA (ret.), was an infantry platoon leader in the 2-7 Cavalry during Operations Pegasus and Delaware. He taught AirLand Battle, military law and counterterrorism at the 6224th U.S. Army Reserve School, was an Army Reserve JAG officer and a trial attorney for more than 40 years. He is CEO of the Arizona Military Museum.