U.S. Army Medical Department, Office of Medical History
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The Vietnam War had its precedents in American military history. At the turn of this century the U.S. Army in the Philippines, only a few years after the end of its trials during the Indian Wars of the American frontier, again fought an enemy that often used guerrilla tactics. In 1898 many American soldiers serving in Cuba suffered the torments of tropical disease. World War II in the Pacific, although conventional in nature, once more subjected American soldiers to the hardships of warfare in the tropics. But advances in weapons and military transport made the Vietnam War a virtually new experience for the American armed forces.

This was especially true for the Army Medical Department. Its experiences with patient evacuation in the Korean War had only foreshadowed the problems it would confront in South Vietnam. Helicopter ambulances in Korea had rarely needed to fly over enemy-held areas, and the terrain of Korea, although rugged, lacked the thick jungles and forests that obstructed the air ambulances in Vietnam. While Army hospitals in Korea had been highly mobile, moving often with the troops, the frontless war in Vietnam resulted in a fixed location for almost all hospitals. French armed forces had used the helicopter for medical evacuation in their unsuccessful struggle in Indochina, but since they had used aircraft that were soon obsolete, their experiences could offer little guidance to the Americans who arrived in Vietnam in 1962.


Records produced by the various U.S. Army air ambulance units in Vietnam show that the Medical Department's new aeromedical evacuation system performed beyond all expectation. Although figures are lacking for some phases of the system's work, enough reports have survived to permit an assessment of what it accomplished. It is, possible both to describe the number and types of patients transported and to compare the risks of air ambulance missions with those of other helicopter missions in the Vietnam War.

Air ambulances transported most of the Army's sick, injured, and wounded who required rapid movement to a medical facility, and also many Vietnamese civilian and military casualties. From May 1962 through March 1973 the ambulances moved between 850,000 and


900,000 allied military personnel and Vietnamese civilians. The Vietnamese, both civilian and military, constituted about one half of the total; U.S. military personnel, about 45 percent; and other non-Vietnamese allied military, about 5 percent. These proportions varied, however, over the course of the war. Before 1965 about 90 percent of the patients were Vietnamese. Then the U.S. buildup began in 1965, and the figure dropped to only 21 percent for 1966. As the United States started to turn over more of the fighting to the South Vietnamese, the number rose until it reached 62 percent in 1970. Unfortunately, exact percentages of wounded, injured, and sick among the air ambulance patients are lacking. Although only about 15 percent of the cases treated by all Army medical personnel in the war were wounded in action, it seems that the percentage of wounded among the air ambulance patients was much higher, between 30 and 35 percent, since the ambulances gave first priority to patients in immediate danger of loss of life or limb, a condition most closely associated with combat wounds. Up to 120,000 of the U.S. Army wounded in action admitted to some medical facility-90 percent of the total-were probably carried on the ambulances. This is about one third of the some 390,000 Army patients that the air ambulances carried to a medical facility.

The widespread use of the air ambulances clearly seems to have reduced the percentage of deaths from wounds that could have been expected if only ground transportation were used. In World War II the percentage of deaths among those Army soldiers admitted to a medical facility was 4.5; in Korea, 2.5. In Vietnam it was 2.6, despite a road network as bad as that in Korea, despite thick jungle and forest that made off-the-road evacuation much more difficult than in Korea, and despite the large numbers of hopeless patients whom the air ambulances brought to medical facilities just before they died. Another statistic-deaths as a percentage of hits-shows more clearly the improvement in medical care: in World War II it was 29.3 percent; in Korea, 26.3 percent; and in Vietnam, only 19 percent. Helicopter evacuation was only one aspect of the Army's medical care in Vietnam, but without that link between the battlefield and the superbly staffed and equipped hospitals, it seems likely that the death rate would have surpassed perhaps even that in World War II.

Measured both by the patients moved and the number of missions flown, the air ambulances were busiest in 1969, when by the end of the year 140 were stationed around the country. Over the course of the war the divisional air ambulances of the lst Cavalry and 101st Airborne constituted only 15 percent of the total. Because of the high maintenance demands of the UH-1, only about 75 percent of the ambulances were flyable at any given moment, although replacement aircraft could sometimes be borrowed from helicopter maintenance


companies. Of the aviators required by the Army tables of organization and equipment, an average of 90 percent was available for duty. Although at times the air ambulances were filled to capacity and even overcrowded, a single mission on the average moved only two patients. In the peak years of U.S. involvement, from 1965 to 1969, a single mission averaged, round trip, about fifty minutes. In the same period the ambulance units used the hoist only once every sixty missions. The helicopters averaged about two missions per workday in 1965, increasing to four missions in 1969.

Statistics also confirm the impression that the air ambulance pilots and crewmen stood a high chance of being injured, wounded, or killed in their one-year tour. About 1,400 Army commissioned and warrant officers served as air ambulance pilots in the war. Theirs was one of the most dangerous types of aviation in that ten-year struggle. About forty aviators (both commanders and pilots) were killed by hostile fire or crashes induced by hostile fire. Another 180 were wounded or injured as a result of hostile fire. Furthermore, forty-eight were killed and about two hundred injured as a result of nonhostile crashes, many at night and in bad weather on evacuation missions. Therefore, slightly more than a third of the aviators became casualties in their work, and the crew chiefs and medical corpsmen who accompanied them suffered similarly. The danger of their work was further borne out by the high rate of air ambulance loss to hostile fire: 3.3 times that of all other forms of helicopter missions in the Vietnam War. Even compared to the loss rate for nonmedical helicopters on combat missions it was 1.5 times as high. Warrant officer aviators, who occasionally arrived in South Vietnam without medical training or an assignment to a unit, were sometimes warned that air ambulance work was a good way to get killed.

One air ambulance operation, the hoist mission, added greatly to these dangers. Although hoist missions were rarely flown, one out of every ten enemy hits on the air ambulances occurred on such occasions. Standard missions averaged an enemy hit only once every 311 trips, but hoist missions averaged an enemy hit once every 44 trips, making them seven times as dangerous as the standard mission. That some 8,000 aeromedical hoist missions were flown during the war further testifies to the bravery of the air ambulance pilots and crewmen.

Doctrine and Lessons Learned

When the first Army air ambulances arrived in Vietnam in April 1962, none of the existing Army guidelines for aeromedical evacuation fitted their needs. Only in August 1963 did the 57th Medical Detachment receive a mission statement, in the form of USARV Regulation 59-1 (12 August 1963). It contained a list of patient


priorities, based on nationality and civilian-military status. It prohibited the use of the air ambulances for nonmedical administrative and logistical purposes, and it outlined the steps to be taken by ground commanders in making a request for an air ambulance. As the war progressed, the regulation was updated periodically to cover various emerging problems. By the end of the war it was twice as long as the August 1963 version, and it elaborated on several problems that had been ignored or treated only briefly in the original-hoist operations, evacuation of the dead, pickup zones reported as insecure, and misclassification of patients. A new category of patient had been designated: tactical urgent, meaning that the evacuation was urgent not because of the patient's wound but because of immediate enemy danger to the patient's comrades. The old categories of urgent, priority, and routine were now defined at length. An appendix and a diagram outlined the requesting unit's responsibilities in preparing a pickup zone. Little was left to the ground commander's imagination.

In spite of this amplification for the benefit of the ground commander, much was still left to the interpretation of the air ambulance commanders and pilots. Controversies over the use of the air ambulances that had surfaced early in the war were at its end untreated and unresolved by any Army regulation or field manual.

One of these problems concerned the best type of organization for air ambulance units. In an article in the August 1957 issue of Medical Journal of the United States Armed Forces, Col. Thomas N. Page and Lt. Col. Spurgeon H. Neel, Jr., had outlined current Army doctrine on aeromedical evacuation. One of their precepts read: "The company-type organization for the aeromedical function is superior to the current cellular detachment concept." But the first two aeromedical evacuation units that deployed to Vietnam were detachments that depended on nearby aviation units for their mess and other logistical needs, and for part of their maintenance. Although two TOE air ambulance companies, the 45th and 498th, were eventually deployed, most of the air ambulances in the war worked in cellular detachments.

After the war several former aviation consultants to the Surgeon General stated that the company structure had provided administrative and logistical advantages that outweighed its disadvantages. Most former detachment commanders and some of the former company commanders, however, emphasized the weakness of the company structure. Because of the dispersed nature of the fighting in Vietnam, the platoons of the companies often were field-sited far from their company headquarters, creating a communication problem and also reducing the effectiveness of the company's organic maintenance facilities that were located at the home base. The detachments, however, had their own limited maintenance facilities, and the pla-


toons organic to an airmobile division could readily draw on its resources. For about one year toward the end of the war an experiment with two medical evacuation battalions had produced encouraging results, but the experiment apparently was too limited to firmly establish the battalion as the ideal medical evacuation unit. No formal statement from the Surgeon General had resolved the issue by the end of the war: a policy of flexibility seems to have evolved by default, allowing the use of whatever type of organization best fitted the geographic region and phase of the war.

In 1957 Page and Neel had also written: "The consensus is that there is no real requirement for a separate communications net for the control of aeromedical evacuation." But the air ambulance units in Vietnam quickly found that tactical command networks were often too busy to permit their use by medical personnel. In September 1966 the commander of the 3d Surgical Hospital wrote: "Casualty control and medical regulating of patient load would be well served by a separate radio net exclusive to the medical service. Accurate knowledge of incoming loads of patients would allow proper notification of hospital personnel and preparation of critical supplies in advance. Multiple switchboards and untrustworthy landlines now prevent the dissemination of information which might aid in the optimal care of patients." Shortly thereafter the USARV regulation on aeromedical evacuation was amended to assign the air ambulance units two frequencies, one for use in I and II Corps Zones and one for III and IV Corps Zones.

In another area, Page and Neel had outlined a point of Army medical doctrine that remained, despite some complaints by combat commanders, inviolate throughout the war: "Within the Army, the Army Medical Service has the basic technical responsibility for all medical evacuation, whether by surface or aerial means .... The Army Medical Service requires sufficient organic aviation of the proper type to enable it to accomplish its continuing mission of rapid evacuation of the severely wounded directly to appropriate medical treatment facilities." The Medical Service received its helicopters in the buildup from 1965 through 1969, and most of the aviators who served as air ambulance commanders, whether commissioned or warrant officers, had received medical training comparable to that given a battalion surgeon's assistant. Only in the first years of the war were the detachments under the operational control of nonmedical aviation units. Medical control of air evacuation did not preclude having nonmedical aviation units evacuate large numbers of patients with only routine wounds, injuries, and illnesses. Page and Neel had written: "The Army Medical Service does not require sufficient organic aviation for the entire Army aeromedical evacuation mission .... The movement of nonemergency patients by air can be accomplished


economically by making use of utility and cargo aircraft in conjunction with normal logistic missions, provided there is adequate medical control over the movement of patients." The twenty-four air ambulances of the 1st Cavalry and 101st Airborne Division also remained outside the jurisdiction of the Army medical command in Vietnam. Even so, all officer and most warrant officer ambulance pilots of the divisions had to pass the Medical Service Corps training program for ambulance pilots; and when the division pilots flew patients directly to a hospital, they were required to radio a 44th Medical Brigade regulating officer for approval of their destination. While some combat commanders objected to medical control over evacuation of their casualties, others resented their inability to subordinate the Dust Off air ambulances to a mission of close and direct support for their particular unit. Although there was usually a considerable difference in rank between the aircraft commander of a Dust Off ship and the irritated ground commander, there apparently were few instances of the commander succeeding in obtaining direct support without first routing his request through prescribed channels. Throughout the war most Army commanders knew that casualties properly classified as urgent would almost always benefit from evacuation in an air ambulance.

One subject not touched upon by Page and Neel proved to be a source of lasting trouble in Vietnam. While the three basic patient classifications - routine, priority, and urgent - survived in the Army regulation until the end of the war, no agreement could be reached on the proper definition of these terms. Most of the controversy dealt with the category "priority," which as originally worded applied to a patient who required prompt medical care not available locally and who should be evacuated within twenty-four hours. In practice, the aeromedical units found that this definition often resulted in overclassification of priority patients as urgent patients, who were expected to be moved immediately. Most ground commanders simply would not take the responsibility of saying that any of their wounded could wait up to twenty-four hours for medical treatment. When the air ambulance units proposed shortening the time limit on priority patients, some staff officers noted that in practice the ambulances were picking up priority patients as soon as possible and that almost no priority patient ever had to wait twenty-four hours for evacuation. So USARV headquarters changed the regulation to read: "Priority: Patients requiring prompt medical care not locally available. The precedence will be used when it is anticipated that the patient must be evacuated within four hours or else his condition will deteriorate to the degree that he will become an urgent case." Even after this amendment, the regulation drew criticism from Maj. Patrick Brady, who argued that there should be only two categories: urgent and


nonurgent. He thought that all missions should be flown as urgent, resources permitting, and that the requestor should be allowed to set his own time limit on nonurgent patients.

This controversy arose partly from the tension between those aviators who, preserving the Kelly tradition, paid scant attention to the security of the landing zone, the weather, or the time of day in deciding whether to accept a mission, and those units and aviators who adopted a cautious approach. The USARV regulation and the published operating procedures of some of the units favored the more cautious approach, calling for gunship escorts on all hoist missions, discouraging night missions except for urgent patients, and prohibiting flight into an insecure pickup zone. Night, bad weather, and reports of recent enemy fire in a pickup zone would keep the cautious pilots from even lifting off on a mission. But none of these would prevent the bolder pilots from making an immediate liftoff, even for a routine patient. Little short of enemy fire would keep the braver pilots, once they were above the landing zone on an urgent or priority mission, from going in. On an urgent mission, a few pilots like Major Kelly, Major Brady, and Mr. Novosel, would even fly into the teeth of enemy bullets to get to wounded. The bolder pilots also adhered closely to the section of the Geneva convention that required all air ambulances to carry no weapons. Although almost all the pilots took along sidearms, many declined the use of gunship escorts or externally mounted M60 machine guns.

The tension between these two approaches to air ambulance work could hardly have been resolved by any command edict, and no attempt was made to do so. The USARV regulation left the ultimate decision on whether to reject or abort a mission entirely in the hands of the individual aircraft commander who received the request. On Brady's first tour in Vietnam, one of his comrades told him that if he kept on taking so many risks he would either be killed or win the Medal of Honor. Consciously preserving the Kelly tradition, and drawing on his vast store of skill and luck, Brady survived and indeed won the nation's highest military award. Most of the pilots, while not quite measuring up to the Kelly tradition, acted bravely and honorably enough to win widespread respect and gratitude from those who served in Vietnam.

A Historical Perspective

What did the Dust Off experience mean to the history of medical evacuation? The concepts developed in Maj. Jonathan Letterman in 1862-medically controlled ambulances and an orderly chain of evacuation that takes each patient no farther to the rear than necessary-are still sound. There will always be a hierarchy of


medical facilities in wartime: the more specialized the care, the more likely it will be infrequently used, and centralized at a point well to the rear of a battlefront, often completely outside the war zone. Modern technology has made it possible to improve enormously the quality and range of care provided at hospitals in or near a war zone, especially in the area of lifesaving equipment and techniques. But the more complicated demands of restorative and recuperative care will probably long remain a duty of medical facilities in the communications zone and the zone of the interior. Helicopter evacuation and modern medical technology have only modified, not destroyed, the value of Letterman's system, particularly in medical care close to the scene of battle.

Because helicopter ambulances usually kept a combat unit within a half hour's flight time from an allied base in Vietnam, it was no longer necessary to set up the traditional hierarchy of medical facilities-a Letterman chain of evacuation. Battalion aid stations and division clearing stations found many of their old duties assumed by immobile and often distant surgical, field, and evacuation hospitals, where most patients, except those in remote areas such as the Central Highlands, were flown directly from the site of wounding. The speed of the helicopter ambulances combined with a proficient medical regulating system after 1966 allow the larger hospitals to specialize in certain types of wounds. Despite these advantages, the simplification of the Letterman chain of evacuation also had its dangers. At times, as during the battle around Dak To in 1967, the nearest hospitals able to take casualties might be too far away to permit direct flights from the battlefield. In times of large-scale casualties, such as the Tet offensive of 1968, central medical facilities unsupported by the triage and surgical services of lower echelon medical facilities, even if there were adequate warning, could find themselves overwhelmed. Sometimes, as during the strike into Laos in 1971, faulty casualty estimates could result in a local shortage of medical helicopters. Furthermore, the less seriously wounded patients of an air ambulance, especially those not requiring major surgery, could often find themselves evacuated farther to the rear than necessary.

Whether the modification of the Letterman system that occurred in Vietnam saves money-by specializing wound care, fixing the location of most surgically equipped hospitals, and reducing the care furnished at the division clearing stations and some of the smaller surgical hospitals-is debatable, given the attendant need to upgrade the larger hospitals in the combat zone and expand the expensive helicopter evacuation system. A more important question is whether the modification improves medical care and saves lives. The Dust Off story suggests that it did help reduce the Army's mortality rate in Vietnam. But it is doubtful whether that experience, in an


undeveloped country and in a war against an enemy with few effective antiaircraft weapons, would prove wholly applicable in a large scale conventional conflict in a more developed theater. In such a conflict there might be a role for truly mobile surgical hospitals, which were not used in Vietnam. Working close to the front, such hospitals would be within range of both ground and air ambulances. The ideas of Jonathan Letterman would still merit the closest attention.