U.S. flag

An official website of the United States government

Skip to main content
Return to topReturn to top

Table of Contents


The Vietnam War had its precedents in American military history. Atthe turn of this century the U.S. Army in the Philippines, only a few yearsafter 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 Americansoldiers serving in Cuba suffered the torments of tropical disease. WorldWar II in the Pacific, although conventional in nature, once more subjectedAmerican soldiers to the hardships of warfare in the tropics. But advancesin weapons and military transport made the Vietnam War a virtually newexperience for the American armed forces.

This was especially true for the Army Medical Department. Its experienceswith patient evacuation in the Korean War had only foreshadowed the problemsit would confront in South Vietnam. Helicopter ambulances in Korea hadrarely needed to fly over enemy-held areas, and the terrain of Korea, althoughrugged, lacked the thick jungles and forests that obstructed the air ambulancesin Vietnam. While Army hospitals in Korea had been highly mobile, movingoften with the troops, the frontless war in Vietnam resulted in a fixedlocation for almost all hospitals. French armed forces had used the helicopterfor medical evacuation in their unsuccessful struggle in Indochina, butsince they had used aircraft that were soon obsolete, their experiencescould offer little guidance to the Americans who arrived in Vietnam in1962.


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

Air ambulances transported most of the Army's sick, injured, and woundedwho required rapid movement to a medical facility, and also many Vietnamesecivilian and military casualties. From May 1962 through March 1973 theambulances 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 ofthe 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 21percent for 1966. As the United States started to turn over more of thefighting to the South Vietnamese, the number rose until it reached 62 percentin 1970. Unfortunately, exact percentages of wounded, injured, and sickamong the air ambulance patients are lacking. Although only about 15 percentof the cases treated by all Army medical personnel in the war were woundedin action, it seems that the percentage of wounded among the air ambulancepatients was much higher, between 30 and 35 percent, since the ambulancesgave first priority to patients in immediate danger of loss of life orlimb, a condition most closely associated with combat wounds. Up to 120,000of the U.S. Army wounded in action admitted to some medical facility-90percent of the total-were probably carried on the ambulances. This is aboutone third of the some 390,000 Army patients that the air ambulances carriedto a medical facility.

The widespread use of the air ambulances clearly seems to have reducedthe percentage of deaths from wounds that could have been expected if onlyground transportation were used. In World War II the percentage of deathsamong 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 muchmore difficult than in Korea, and despite the large numbers of hopelesspatients whom the air ambulances brought to medical facilities just beforethey died. Another statistic-deaths as a percentage of hits-shows moreclearly 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 evacuationwas only one aspect of the Army's medical care in Vietnam, but withoutthat link between the battlefield and the superbly staffed and equippedhospitals, it seems likely that the death rate would have surpassed perhapseven 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 140were stationed around the country. Over the course of the war the divisionalair ambulances of the lst Cavalry and 101st Airborne constituted only 15percent 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 helicoptermaintenance


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

Statistics also confirm the impression that the air ambulance pilotsand crewmen stood a high chance of being injured, wounded, or killed intheir one-year tour. About 1,400 Army commissioned and warrant officersserved as air ambulance pilots in the war. Theirs was one of the most dangeroustypes of aviation in that ten-year struggle. About forty aviators (bothcommanders and pilots) were killed by hostile fire or crashes induced byhostile fire. Another 180 were wounded or injured as a result of hostilefire. Furthermore, forty-eight were killed and about two hundred injuredas a result of nonhostile crashes, many at night and in bad weather onevacuation missions. Therefore, slightly more than a third of the aviatorsbecame casualties in their work, and the crew chiefs and medical corpsmenwho accompanied them suffered similarly. The danger of their work was furtherborne out by the high rate of air ambulance loss to hostile fire: 3.3 timesthat of all other forms of helicopter missions in the Vietnam War. Evencompared to the loss rate for nonmedical helicopters on combat missionsit was 1.5 times as high. Warrant officer aviators, who occasionally arrivedin South Vietnam without medical training or an assignment to a unit, weresometimes warned that air ambulance work was a good way to get killed.

One air ambulance operation, the hoist mission, added greatly to thesedangers. Although hoist missions were rarely flown, one out of every tenenemy hits on the air ambulances occurred on such occasions. Standard missionsaveraged an enemy hit only once every 311 trips, but hoist missions averagedan enemy hit once every 44 trips, making them seven times as dangerousas the standard mission. That some 8,000 aeromedical hoist missions wereflown during the war further testifies to the bravery of the air ambulancepilots 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 fittedtheir needs. Only in August 1963 did the 57th Medical Detachment receivea 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 prohibitedthe use of the air ambulances for nonmedical administrative and logisticalpurposes, and it outlined the steps to be taken by ground commanders inmaking a request for an air ambulance. As the war progressed, the regulationwas updated periodically to cover various emerging problems. By the endof the war it was twice as long as the August 1963 version, and it elaboratedon several problems that had been ignored or treated only briefly in theoriginal-hoist operations, evacuation of the dead, pickup zones reportedas insecure, and misclassification of patients. A new category of patienthad been designated: tactical urgent, meaning that the evacuation was urgentnot because of the patient's wound but because of immediate enemy dangerto the patient's comrades. The old categories of urgent, priority, androutine were now defined at length. An appendix and a diagram outlinedthe requesting unit's responsibilities in preparing a pickup zone. Littlewas 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 commandersand pilots. Controversies over the use of the air ambulances that had surfacedearly in the war were at its end untreated and unresolved by any Army regulationor field manual.

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

After the war several former aviation consultants to the Surgeon Generalstated that the company structure had provided administrative and logisticaladvantages that outweighed its disadvantages. Most former detachment commandersand some of the former company commanders, however, emphasized the weaknessof the company structure. Because of the dispersed nature of the fightingin Vietnam, the platoons of the companies often were field-sited far fromtheir company headquarters, creating a communication problem and also reducingthe effectiveness of the company's organic maintenance facilities thatwere located at the home base. The detachments, however, had their ownlimited 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 medicalevacuation battalions had produced encouraging results, but the experimentapparently was too limited to firmly establish the battalion as the idealmedical evacuation unit. No formal statement from the Surgeon General hadresolved the issue by the end of the war: a policy of flexibility seemsto have evolved by default, allowing the use of whatever type of organizationbest fitted the geographic region and phase of the war.

In 1957 Page and Neel had also written: "The consensus is thatthere is no real requirement for a separate communications net for thecontrol of aeromedical evacuation." But the air ambulance units inVietnam quickly found that tactical command networks were often too busyto permit their use by medical personnel. In September 1966 the commanderof the 3d Surgical Hospital wrote: "Casualty control and medical regulatingof patient load would be well served by a separate radio net exclusiveto the medical service. Accurate knowledge of incoming loads of patientswould allow proper notification of hospital personnel and preparation ofcritical supplies in advance. Multiple switchboards and untrustworthy landlinesnow prevent the dissemination of information which might aid in the optimalcare of patients." Shortly thereafter the USARV regulation on aeromedicalevacuation 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 medicaldoctrine that remained, despite some complaints by combat commanders, inviolatethroughout the war: "Within the Army, the Army Medical Service hasthe basic technical responsibility for all medical evacuation, whetherby surface or aerial means .... The Army Medical Service requires sufficientorganic aviation of the proper type to enable it to accomplish its continuingmission of rapid evacuation of the severely wounded directly to appropriatemedical treatment facilities." The Medical Service received its helicoptersin the buildup from 1965 through 1969, and most of the aviators who servedas air ambulance commanders, whether commissioned or warrant officers,had received medical training comparable to that given a battalion surgeon'sassistant. Only in the first years of the war were the detachments underthe operational control of nonmedical aviation units. Medical control ofair evacuation did not preclude having nonmedical aviation units evacuatelarge numbers of patients with only routine wounds, injuries, and illnesses.Page and Neel had written: "The Army Medical Service does not requiresufficient organic aviation for the entire Army aeromedical evacuationmission .... The movement of nonemergency patients by air can be accomplished


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

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


nonurgent. He thought that all missions should be flown as urgent, resourcespermitting, and that the requestor should be allowed to set his own timelimit on nonurgent patients.

This controversy arose partly from the tension between those aviatorswho, preserving the Kelly tradition, paid scant attention to the securityof the landing zone, the weather, or the time of day in deciding whetherto accept a mission, and those units and aviators who adopted a cautiousapproach. The USARV regulation and the published operating procedures ofsome of the units favored the more cautious approach, calling for gunshipescorts on all hoist missions, discouraging night missions except for urgentpatients, and prohibiting flight into an insecure pickup zone. Night, badweather, and reports of recent enemy fire in a pickup zone would keep thecautious pilots from even lifting off on a mission. But none of these wouldprevent the bolder pilots from making an immediate liftoff, even for aroutine 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, MajorBrady, and Mr. Novosel, would even fly into the teeth of enemy bulletsto get to wounded. The bolder pilots also adhered closely to the sectionof the Geneva convention that required all air ambulances to carry no weapons.Although almost all the pilots took along sidearms, many declined the useof gunship escorts or externally mounted M60 machine guns.

The tension between these two approaches to air ambulance work couldhardly have been resolved by any command edict, and no attempt was madeto do so. The USARV regulation left the ultimate decision on whether toreject or abort a mission entirely in the hands of the individual aircraftcommander who received the request. On Brady's first tour in Vietnam, oneof his comrades told him that if he kept on taking so many risks he wouldeither be killed or win the Medal of Honor. Consciously preserving theKelly tradition, and drawing on his vast store of skill and luck, Bradysurvived and indeed won the nation's highest military award. Most of thepilots, while not quite measuring up to the Kelly tradition, acted bravelyand honorably enough to win widespread respect and gratitude from thosewho 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 controlledambulances and an orderly chain of evacuation that takes each patient nofarther to the rear than necessary-are still sound. There will always bea hierarchy of


medical facilities in wartime: the more specialized the care, the morelikely it will be infrequently used, and centralized at a point well tothe rear of a battlefront, often completely outside the war zone. Moderntechnology has made it possible to improve enormously the quality and rangeof care provided at hospitals in or near a war zone, especially in thearea of lifesaving equipment and techniques. But the more complicated demandsof restorative and recuperative care will probably long remain a duty ofmedical 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 medicalcare close to the scene of battle.

Because helicopter ambulances usually kept a combat unit within a halfhour's flight time from an allied base in Vietnam, it was no longer necessaryto set up the traditional hierarchy of medical facilities-a Letterman chainof evacuation. Battalion aid stations and division clearing stations foundmany of their old duties assumed by immobile and often distant surgical,field, and evacuation hospitals, where most patients, except those in remoteareas such as the Central Highlands, were flown directly from the siteof wounding. The speed of the helicopter ambulances combined with a proficientmedical regulating system after 1966 allow the larger hospitals to specializein certain types of wounds. Despite these advantages, the simplificationof the Letterman chain of evacuation also had its dangers. At times, asduring the battle around Dak To in 1967, the nearest hospitals able totake casualties might be too far away to permit direct flights from thebattlefield. In times of large-scale casualties, such as the Tet offensiveof 1968, central medical facilities unsupported by the triage and surgicalservices of lower echelon medical facilities, even if there were adequatewarning, could find themselves overwhelmed. Sometimes, as during the strikeinto Laos in 1971, faulty casualty estimates could result in a local shortageof medical helicopters. Furthermore, the less seriously wounded patientsof an air ambulance, especially those not requiring major surgery, couldoften find themselves evacuated farther to the rear than necessary.

Whether the modification of the Letterman system that occurred in Vietnamsaves money-by specializing wound care, fixing the location of most surgicallyequipped hospitals, and reducing the care furnished at the division clearingstations and some of the smaller surgical hospitals-is debatable, giventhe attendant need to upgrade the larger hospitals in the combat zone andexpand the expensive helicopter evacuation system. A more important questionis whether the modification improves medical care and saves lives. TheDust Off story suggests that it did help reduce the Army's mortality ratein Vietnam. But it is doubtful whether that experience, in an


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