The Pilot At Work
From 1965 to 1970 the U.S. Army in Vietnam perfected techniques of aeromedicalevacuation that helped save the lives of hundreds of thousands of Americansand Vietnamese, both friend and foe, both soldiers and civilians. Manyof the techniques had been worked out in the early years of U.S. involvementin Vietnam, from 1962 to 1965, when only the 57th and 82d Medical Detachmentsoffered air ambulance service to the U.S. and South Vietnamese Armies.After the buildup of American forces began in 1965, the helicopters, procedures,and rescue equipment were improved and sometimes tested on mass casualties.Refinements of the system were made after the Tet offensive in 1968, andArmy air ambulances evacuated more patients in 1969 than in any other yearof the war. Then, as it began to withdraw its forces from Vietnam, theU.S. Army set up a training program to pass on its skills in air ambulancework to the South Vietnamese Army and Air Force. Assisting the developmentof the helicopters and rescue equipment and acquiring the skills neededto use them demanded exceptional imagination, dedication, and compassion,both of U.S. Army medical personnel and the South Vietnamese who learnedfrom them.
The UH-1 Iroquois ("Huey")
When it entered the Vietnam War the U.S. Army lacked a satisfactoryaircraft for medical evacuation. As early as 1953 the Aviation Sectionof the Surgeon General's Office had specified the desirable characteristicsof an Army air ambulance. It was to be highly maneuverable for use in combatzones, of low profile, and capable of landing in a small area. It was tocarry a crew of four and at least four litter patients, yet be easily loadedwith litters by just two people. It had to be able to hover with a fullpatient load even in high altitude areas, and to cruise at least ninetyknots per hour fully loaded. But in 1962 the Army's basic utility aircraft,the UH-1B made by Bell Aircraft Corporation, still did not meet these standards.It was, however, a small craft with a low profile, and the Army's MSC pilotscould console themselves with the fact that the Huey was a far better airambulance than the one their predecessors had flown in the Korean War.It had nearly twice the speed and endurance of the H-13 Sioux, and it
could carry patients inside the aircraft, allowing a medical corpsmanto administer in-flight treatment.
In almost all other respects it was less than perfect. One of its majorproblems was the comparatively low power of the engine. The critical factorin planning all helicopter flights with heavy cargoes is what pilots knowas "density altitude"-the effective height above sea level computedon the basis of the actual altitude and the air temperature. The warmerthe air, the less its resistance to the rotor blades and the less liftthey produce. Because of its lack of fixed wings, which permit a powerlessglide, a helicopter whose engine quits or fails to produce adequate powerat a high density altitude can easily crash. Given enough forward airspeedand height, most helicopters, including all the Huey models, can drop tothe earth and still land if the power falls, using the limited lift producedby the freely-spinning rotor blades. But this maneuver, called an autorotation,is virtually impossible to execute in a low-level, hovering helicopter.A writer for the Marine Corps suggests that this explains "...why,in generality, airplane pilots are open, clear-eyed, buoyant extrovertsand helicopter pilots are brooders, introspective anticipators of trouble."
Although the A- and B-model Huey engine often lacked enough power towork in the heat and high altitudes of South Vietnam, it was much strongerthan earlier Army helicopter engines. A great advance in helicopter propulsionhad come in the 1950s with the adaptation of the gas turbine engine tohelicopter flight. The piston-drive engines used in Korea and on the Army'sUH-34 utility helicopters in the 1950s and early 1960s had produced onlyone horsepower for each three pounds of engine weight. The gas turbineengines installed on the UH-1 Hueys, which the Army first accepted in 1961,had a much more favorable efficiency ratio. This permitted the constructionof small, low-profile aircraft that was still large enough to carry a crewof four and three litter patients against the back wall of the cabin. Butthe high density altitudes encountered in II Corps Zone in Vietnam meantthat the UH-1A and UH-1B with a full crew-pilot, aircraft commander, crewchief, and medical corpsman-often could carry no more than one or two patientsat a time.
In the early 1960s, shortly after the first U.S. Army helicopters weresent to South Vietnam, the Army began to use an improved ver-sion of theUH-1B: the UH-1D, which had a longer body with a cabin that could holdsix litter patients or nine ambulatory patients. The longer rotor bladeon the UH-1D gave it more lifting power, but high density altitudes inthe northern two corps zones, where U.S. troops did most of their fighting,still prevented Dust Off pilots from making full use of the aircraft'scarrying capacity. Finally in 1967 the commander of the 4th Infantry Divisionregistered a complaint about his aeromedical evacuation support.
The 498th Medical Company, which served this area, had performed 100hoist missions from July 1966 to February 1967 but had aborted 12 of them,3 because of mechanical failures of the hoist and 9 because of the inabilityof the helicopter to hover. In March 1967 at Nha Trang, the staff of IField Force, Vietnam, held a conference of various personnel involved inaeromedical evacuation in northern Vietnam. The conference noted the lowengine power of the UH-1D's working in the Central Highlands, especiallyof those with the 498th Medical Company and the Air Ambulance Platoon ofthe 1st Cavalry.
In July 1967 the arrival at Long Binh of the 45th Medical Com-pany (AirAmbulance), equipped with new, powerful UH-1H's marked the end to the Huey'spropulsion problem. Headquarters, I Field Force, Vietnam, soon conducteda test of the engine power of the UH-1D, the Kaman HH-43 "Husky,"and the new UH-1H with an Avco Corporation T-53-L-13 engine. The studyshowed that the maximum load of an aircraft hovering more than about twentyfeet above the ground (out of ground effect) on a normal 95º F. dayin the western Highlands was 184 pounds for the UH-1D with an L-11 engine,380 pounds for the Husky, and 1,063 pounds for the UH-1H with an L-13 engine.This meant that on such a day the UH-1D could not perform a hoist mission;the Husky could pull at most two patients.; and the UH-1H could pull fivehoist patients. The L-13, rated at 27 percent more horsepower than theL-11, consumed 9 percent less fuel. The other air ambulance units in Vietnamobviously had to start using the UH-1H.
On 21 January 1968 the last UH-1D air ambulance in the U.S. Army, Vietnam,left the 57th Medical Department and became a troop transport in the 173dAssault Helicopter Battalion at Lai Khe. Now the entire fleet of air ambulanceshad powerful UH-1D's, solving many of the problems caused by high densityaltitudes, hoist missions, and heavy loads. Also, unlike most of the UH-1D's,the UH-1H's were fully instrumented for flight at night and in poor weather.They proved to be rugged machines, needing comparatively little time formaintenance and repairs. Like the earlier models, the H-models came withskids rather than wheels, to permit landing on marshy or rough terrain.The UH-1H's only important departure from the 1953 specifications of theAviation Section was its inability to sustain flight if part or all ofone rotor blade were missing. It was a single-engine craft with only twomain rotor blades; the loss of all or part of one main blade would createan untenable imbalance in the propulsion system. And the Army version ofthe UH-1H had a flammable magnesium-aluminum alloy hull. Still, in mostways the UH-1H proved to be an ideal vehicle for combat medical evacuation.
The terrain in Vietnam - a mixture of mountains, marshy plains, andjungles- dictated the use of the helicopter for almost all transport. Thechanges in the design of the UH-1 Iroquois and its equipment during theVietnam conflict stemmed largely from the problems presented by that difficultterrain. Early in the war the 57th Detachment recognized the need for somemeans of getting troops up to a helicopter hovering above ground obstaclesthat prevented a landing. The 57th sorely needed such a device for usein heavily forested areas, where until then medical evacuations had requiredmoving the wounded and sick to an open area or cutting a pickup zone outof the jungle. During three military operations against the Viet Cong inWar Zone D from November 1962 to March 1963, the South Vietnamese Armyand their American advisers became acutely aware of this problem. The thickjungles in the area made resupply and medical evacuation by helicopterextremely difficult. Some of the South Vietnamese units carried their woundedfor as long as four days before finding a suitable landing area for theUH-lAs. The problem was most acute when soldiers were wounded in the firstfew days of an operation, before reaching their first objective. This forcedthe ground commander either to delay his mission while sidetracking toa pickup zone, to carry the wounded with the assault column, or to leavethe casualties behind with a few healthy soldiers for protection
In attacking this problem, the armed services and their civilian contractorsdevised two fanciful and ultimately unsuccessful devices. Each entailedloading the helicopter while it hovered above the obstacles that surroundedthe wounded below. The XVIII Airborne Corps at Fort Bragg devised a collapsiblebox-like platform that the ground troops were to strap to the upper reachesof a large tree. After the helicopter had dropped the platform to the soldierson the ground, they would climb the tree, attach the platform, bring upthe wounded, and wait while the helicopter moved into a hover just abovethe platform and the crew extended a rigid ladder four feet below the aircraftskids. Supplies would then be moved down and wounded or sick soldiers upthe ladder. Tests revealed the absurdity of the device: wounded troopscould hardly be moved to the top of a tree with ease, and the platformitself proved difficult to secure in the upper reaches of dense, multi-layeredjungle.
A variation on this theme, the "Jungle Canopy Platform System,"consisted of two stainless steel nets and a large platform. From the hoveringhelicopter the crew would unroll the nets onto the top of the jungle canopy,so that they intersected at midpoint; then the crew would lower the platformonto the intersection of the nets and signal the pilots to land on it.Troops and supplies could then move to and from the aircraft. The 1st CavalryDivision tested the device in Viet-
nam during noncombat operations; actual combat reports on it could notbe obtained because no unit would use it under those conditions. Withoutthe platform the nets worked well for deploying troops but proved unreliablefor other uses, such as medical evacuation. The test report concluded:"Based on commanders' reluctance to use the system, there appearsto be no current requirement for the Jungle Canopy Platform System."
Despite these two failures, the Army did develop a piece of supplementalequipment for the Huey that both advanced the art of medical evacuationand placed extraordinary new demands on the air ambulance pilots: the personnelrescue hoist. The hoist was a winch mounted on a support that was anchoredto the floor and roof of the helicopter cabin, usually just inside theright side door behind the pilot's seat. When the door was open, the hoistcould be rotated on its support to position its cable and pulleys outsidethe aircraft, clear of the skids, so that the cable could be lowered toand raised from the ground. After a UH-1 was outfitted with the necessaryelectrical system, the aircraft crew could quickly install or remove thehoist. On a hoist mission, while the aircraft hovered, the medical corpsmanor crew chief would use the hoist cable to lower any one of several typesof litters or harnesses to casualties below. If a wounded soldier and hiscomrades were unfamiliar with the harness or litter, the crew chief wouldsometimes lower a medical corpsman with the device; then the hoist wouldraise both the medic and the casualty to the helicopter. The standard hoisteventually installed on the UH-1D/H could lift up to 600 pounds on oneload and could lower a harness or litter about 250 feet below the aircraft.
As early as November 1962 the Surgeon General's Office had said thatthe Army's air ambulances needed a hoisting device. Under further pressurefrom the 57th Medical Detachment, the Surgeon General had the Army contractwith Bell Aircraft Corporation and the Breeze Corporation for the personnelrescue hoist. The U.S. Army Medical Test and Evaluation Activity experimentedwith the new hoist at Fort Sam Houston in April and May 1965 and recommendedthat it be adopted with minor modifications.
In May 1966 the first hoists began arriving in Vietnam, and on 17 May,Capt. Donald Retzlaff of the 1st Platoon, 498th Medical Company, at NhaTrang, flew the first hoist mission in Vietnam. But within a week the hoistproved unreliable, prone to jam and break during a lift. After being groundedfor two months for repairs and redesigning, the hoist, now modified, wentback into service. It continued to be a maintenance problem for the restof the war, but it functioned well enough to save several thousand lives.
Although air ambulance pilots began to use the hoist in Vietnam in August1966, their commanders soon complained about the ex-
traordinary hazards it brought to their work. The UH-lD was alreadyburdened with a heavy single sideband (high frequency) radio and a navigationsystem; the extra weight of the hoist com-pounded the problem of the underpoweredL-11 engine. Since the crew chief worked on the same side of the aircraftas the hoist, the helicopter was heavily overweighted on one side, anda strong gust of wind from the other side could endanger the craft's stability.The operation also demanded great strength and concentration of the pilots,especially if winds were gusting or if trees or the enemy forced a downwindor crosswind hover. The danger of mechanical troubles was obvious: almostby definition no emergency landing site was nearby, and even if it were,the ship usually was hovering at a height that precluded an autorotationaltouchdown in an emergency.
Adding to the tenseness of such a mission, the crews knew that the mostvulnerable target in the war was a helicopter at a high hover. The precautionsthat had to be taken against sudden enemy fire proved especially taxingon the pilots. The men in the rear of the aircraft cabin would set theintercom switches on their helmets to "hot mike," allowing themto communicate with the rest of the crew without depressing their microphonebuttons. While working the hoist or putting down suppressive fire the crewchief and medical corpman could keep the pilot informed of his nearnessto trees or other hazards. While listening to this chatter, the pilotsalso had to be in radio contact with the people on the ground. In December1966 an officer of the 1st Cavalry Division in the Central Highlands complained:
We are very dissatisfied with the hoist and any of itsassociated equipment. Mainly because we've been shot up pretty badly twiceduring Operation THAYER while in position for hoist extraction. Fortunatelyso far we've had only two crew members slightly wounded. On both occasionsthe VC haven't fired a shot in the last ten to thirty minutes. Then, justas the hook enters the pickup site, he cuts loose. He is so close to ourtroops on the ground ... the armed escort ships can't fire for fear ofhitting our own troops.
The hook on the end of the hoist cable could accept several types ofrescue devices. A traditional rescue harness worked well for pulling uplightly injured soldiers, but it proved difficult and often impossibleto lower through the thick upper vegetation of Vietnam's forests and jungles.Seriously wounded soldiers usually had to be placed in the rigid wire Stokeslitters and raised horizontally; but this too caused problems in thickjungles and forests. For the lightly wounded and the less seriously wounded,the air ambulances almost always used a device designed early in the war-a collapsible seat called the forest penetrator, which could easily belowered through dense jungle canopy. Developed by the Kaman Corporation,the penetrator weighed twenty pounds, and had three small, paddle-likeseats that
could be rotated upwards to lock into place against the sides of thepenetrator's narrow, three-foot long, bullet-shaped body. Once to the ground,the seats could be lowered and the wounded strapped on with chest belts.Although the version accepted by the Army had no protection for the casualty'shead as he was raised up through the foliage, this seldom proved a problem.The first eight forest penetrators arrived in Vietnam in mid-June 1966,but extensive testing of the device with the new hoists was delayed untilSeptember and October. Medical personnel then found the device satisfactoryand it became the normal means of lifting a conscious casualty. Unconscioussoldiers were often lifted head up, in a device known as the semi-rigidlitter: a flexible canvas jacket with a lining of wood straps and a rigidhead cover.
Even when the penetrator was used, a hoist mission took considerablylonger than usual at the pickup zone. Pilots flying the first missionsfound their ships often subject to accurate enemy fire. On 1 November 1966the 283d Detachment at Tan Son Nhut got a request from a ground unit notfar outside Saigon's noise and bustle. The unit had casualties deep underthe jungle and needed a hoist to get them out. In the 283d, Capt. JamesE. Lombard and 1st Lt. Melvin J. Ruiz had the only ship fitted with a hoist.
As soon as they left the ground at Tan Son Nhut they radioed the groundunit and asked whether it had any gunships standing by or had asked forany. The unit answered that it had requested them but had no idea how longthey would take getting there. Three minutes later Lombard and Ruiz arrivedover the pickup site. Lombard told the troops on the ground that he wouldhave to have gunship support before he could land. He radioed a gunshipunit at Bien Hoa, a five minute flight away, and asked them to launch ateam to cover his mission. He was told there would be a thirty minute delay.The ground unit commander than started a sales pitch: there had been onesniper, but they had got him, the area was secure now, they had two criticallywounded. Lombard agreed to come down.
The ground unit popped a smoke grenade, and the Dust Off ship came toa hover over the spot where wisps of colored smoke drifted up through thetrees. The crew chief played out the hoist cable. The forest penetratorwas ten feet below the skids when an automatic weapon opened up on thehelicopter from the right side. Bullets whined and zinged through the aircraft,and the pilot's warning lights lit up like a Christmas tree. Lombard brokeoff the hover. The hydraulics were gone and the crew heard crunching andgrumbling sounds from the transmission. They headed east toward a safehaven at Di An, a four minute flight away. Suddenly the engine quit. Luckilywithin reach of their glide path lay an open area to which they shot anautorotation. With the controls only half working, Lombard had to makea running landing, skidding along the ground. The ship tipped
well forward on its skids then rocked back to a stop. The engine compartmentwas on fire. The crew got out as fast as possible, the pilots squeezingbetween the door frame and their seats' sliding armor side plates, whichwere locked in the forward position. They started to run from the aircraftwhen they realized that their rifles and ammunition were still inside.The medical corpsman dashed back inside, grabbed the rifles and bandoliers,jumped back out, and distributed the arms.
They looked around and decided that they had overflown the enemy, whonow separated them from the friendly unit with the casualties. Rather thanhead into a possible ambush, they started toward a knoll in the directionof Lon Binh. Unknown to them another platoon of the friendly company wasout on a sweep headed in their direction. On the ground the crew was completelyout of their environment. Their loaded M16's cocked on automatic, theywere ready to shoot the first blade of grass that moved. Suddenly theyheard the thump, thump, thump of troops running toward them. They stopped,waited, then saw U.S. troops coming at them through the bush.
They all went back to the landing zone, where they set up a small defensiveperimeter. Later that afternoon, the platoon that had called in the requestcut its way out of the jungle and joined them. Its two wounded had diedon the way out. The company commander radioed Di An and asked its mortarsto start laying a protective barrage around the perimeter. The first salvolanded on the company and wounded many of them. The commander radioed foranother Dust Off. Two hours later as dusk approached, a Dust Off ship fromthe 254th Detachment flew in with a gunship escort. In several trips itevacuated nineteen wounded soldiers, the two dead, and the crew from the283d. Lombard and Ruiz had flown the first of many hoist missions thatresulted in the downing of an air ambulance. But the hoist had clearlyadded a new dimension to utility of the helicopter in Vietnam. Despitethe new danger it brought to their work, the air ambulance crews respondedwith courage and dedication.
Air ambulances received their missions either aloft in the aircraft,at the ambulance base, or at a standby base, usually near or at a battalionor brigade headquarters. The coverage given by the ambulances was eitherarea support (to all allied units in a defined area) or direct support(to a particular unit involved in an operation). Direct support, in effect,dedicated the aircraft to a particular combat unit, and it usually relievedthe aircraft commander of the need to receive mission authorization fromhis operations officer. Both air ambulances organic to combat units andnonorganic aircraft flew direct support missions.
Most air ambulance missions, however, originated during area support.An American or allied patrol would take casualties, usually in daylight,from enemy sniper fire, mines, or other antipersonnel devices. The patrolcommander and medical corpsman would decide whether the casualties neededto be evacuated by helicopter. If a Dust Off or Medevac aircraft were needed,the patrol would, if its radio were powerful enough, send its request directlyto the air ambulances or their operations control. If this were not possible,the patrol would use its tactical radio frequency to send the request backto its battalion headquarters. Whichever method was used, the request hadto contain much information: coordinates of the pickup site, the numberand types (litter or ambulatory) of patients, the nature and seriousnessof the wounds or illness, the tactical radio frequency and call sign ofthe unit with the patients, any need for special equipment (such as thehoist, whole blood, or oxygen), the nationality of the patients, visualfeatures of the pickup zone (including any smoke, lights, or flares tobe used by the ground unit), the tactical security of the pickup zone,and any weather or terrain hazards. The first four elements were critical:with them a mission could be flown; without them no air ambulance couldguarantee a response.
Two elements of any request were open to considerable interpretationby the ground commander and his medical corpsmen: the seriousness of themedical problem and the security of the pickup zone. Three levels of patientclassification were used: urgent, priority, and routine. Urgent patientswere those in imminent danger of loss of life or limb; they demanded animmediate response from any available air ambulance. Priority patientswere those with serious but not critical wounds or illness; they couldexpect up to a four-hour wait. In theory a medical corpsman had to ignorethe suffering of a patient in determining his classification: a soldierin great pain, with a foot mangled by a mine, warranted, if his bleedingwere stanched, only a priority rating. In practice, despite the considerableefforts of aeromedical personnel, any patient bleeding or in great painusually received an urgent classification. just as many patients were overclassified,many dangerous pickup zones were reported as secure, and this too was understandable.Although some air ambulance units tried to fight the policy, Army doctrinelimited the ground unit's responsibility in reporting on a pickup zone:if the unit's soldiers could safely stand up to load the casualties, thepickup zone could be reported as secure. So the air ambulance crew couldnever be sure that the airspace more than ten feet above the ground wouldbe safe. It was highly important for an aircraft commander approachinga pickup zone to establish radio contact with the ground unit and learnas much as possible about enemy forces near the zone.
If the ground unit with the patient had to send its evacuation requestthrough its battalion headquarters, the headquarters would make sure therequest had all essential information and then either send it directlyover the established air ambulance radio frequency or, if it lacked theproper radios, forward it to brigade headquarters, who almost always couldcommunicate directly with the air ambulance operations officer.
Once an air ambulance received an urgent request, its personnel droppedany priority or routine tasks and headed toward the pickup zone. The aircraftcommander performed a variety of duties of such a mission. He supervisedthe work of the pilot and two crewmen, and worked as copilot and navigator.En route he monitored both the tactical and air ambulance frequencies,and talked to the ground unit with the patient. Once over the pickup zone,he surveyed the area and decided whether to make the pickup, with due regardto urgency, security, weather, and terrain. If he decided to land he hadto choose directions and angles of approach and takeoff. If problems developedat the pickup zone he had to decide whether to abort the mission. Oncethe pickup was made, he had to choose and receive confirmation on the suitabilityof a destination with medical facilities. He usually sat in the left frontseat, leaving the right seat to the pilot, who needed a view of the hoiston the side and the flight control advantages of the right side position.Usually the commander left the en route flying to the pilot, but sometimesflew the final approach and the takeoff, especially at an open pickup zone.During a hover on a hoist mission he and the pilot alternated on the controlsevery five minutes.
This practice of flying with two pilots originated in the early daysof U.S. military involvement in Vietnam. Since the Korean War, helicopterdetachments had flown with one pilot in the cockpit. The transportationaviation units which were in Vietnam when the 57th medical detachment deployedthere in 1962 already had made it a policy to fly their H-21's with twopilots in the cockpit. There were convincing reasons. If a solo pilot werewounded or killed by enemy gunfire his crew and ship would probably belost, but a second pilot could take over the controls. A solo pilot alsostood a good chance of getting lost over the sparsely populated Vietnamesecountryside, where seasonal changes in precipitation produced great changesin the features of the terrain, making dead reckoning and pilotage difficulteven for a pilot with excellent maps and aerial photographs. A second pilotcould act as a navigator en route to and from a pickup zone.
The 57th quickly learned the value of two-pilot missions and asked forauthorization to fly them. The denial they received referred to the officialoperator's manual for the UH-1, which said that the helicopter, althoughequipped for two pilots, could be flown by one. Nevertheless, with sevenaviators and only four aircraft, and one of those
usually down for maintenance, the 57th usually flew their missions withtwo pilots up front. All the air ambulance units that followed adoptedthis practice, and eventually they obtained authorizations to do so.
Besides the two pilots, an air ambulance usually carried a crew chiefand medical corpsman. The crew chief's most important preflight duty waspreventive maintenance: keeping the aircraft flight-worthy through properand timely inspections and repairs. He also had to make sure that the aircrafthad all essential tools, equipment, and supplies on board. The medicalcorpsman's only vital preflight duty was to supply the craft with the smallamount of medical supplies that could be used in the short time taken bymost evacuation flights: a basic first aid kit, morphine, intravenous fluids,basic resuscitative equipment, and scalpels and tubes for tracheostomies.At the pickup zone the crew chief and corpsman often worked together toload the casualties. If the hoist had to be used, one of them would operateit on the right side of the aircraft while the other stood in the oppositedoor, armed with a rifle to suppress enemy fire and to see that the aircraftstayed at a safe distance from obstacles. Once the patients were loaded,the crew chief helped the corpsman give their medical aid.
The standard operating procedure of an air ambulance unit usually requiredone aircraft crew to be on alert at all times in "first up" status,ready to respond immediately to an urgent request. Like all ambulance crews,the men sprang into action as soon as the siren in their lounge went off.Most units practiced often to cut the precious minutes needed to get theiraircraft, warm the engine, and lift off. Many could get off in less thanthree minutes, unless the unit commander demanded a certain amount of preflightplanning. Once aloft, the aircraft commander would open his radio to theDust Off frequency and receive his assignment from the radio operator backat the base.
He then turned the ship toward his objective, and at some point en routeswitched to the tactical frequency of the ground unit with the casualties.This allowed him to reassure the unit that help was on the way, assistthe medical aidman on the ground in preparing for the evacuation, and checkwith the ground commander on dangers from the terrain, weather, or enemy.The method of approach to the pickup zone varied. Some units specifieda standard approach, such as a steep, rapid descent from high altitude.But some of the most respected commanders believed in letting the aircraftcommander use the many variables of the situation to determine the fastest,safest means of getting down to the wounded.
On the ground the medical corpsman and the crew chief usually left theaircraft, put the patients on litters, and loaded them onto the ship. Abouthalf the time the casualty would not have received any medical treatmentbefore he reached the air ambulance. When the hoist first went into operation,medical personnel publicized it and
offered training in its use to ground combat and medical personnel.This reduced the likelihood that the medical corpsman would have to belowered during a hoist mission to help load the patients, allowing eitherthe corpsman or the crew chief to put down suppressive fire while the otherlowered and raised the hoist cable. A few units, especially the organicair ambulances, routinely carried a fifth crewman during a hoist mission-agunner to protect the ship, its crew, and its casualties.
Once the patients were aboard and safely secured, the pilot took off.The corpsman tried to find and treat the most serious patient, and reportthe nature of the problem to the aircraft commander. The decision on whereto fly the patients then entered the medical regulating network. The aircraftcommander radioed the nearest responsible medical regulating officer, whoconfirmed or altered the commander's choice of destination. This choicewas based on the commander's knowledge of the specialized surgical capabilitiesof the hospitals in his area and on his daily morning briefing as to thecurrent surgical back- log in these hospitals. Standard practice was totake the most serious patient directly to a nearby hospital known to haveall the equipment and care he immediately needed. If that hospital thendetermined that he needed more sophisticated care than it could offer,he was backhauled as far to the rear as possible. A secondary objectivewas to take the patient to the hospital in the area that had the smallestsurgical backlog, to reduce the time between wounding and the start ofsurgery. The supporting medical group in each area of operations usuallyassigned, at least after 1966, a forward medical regulating officer toeach combat brigade headquarters, and those regulators kept aware of themost current surgical backlogs in all nearby hospitals. Since they hadmore current information on surgical backlogs than the aircraft commanders,the regulators had the authority to change the commander's choice of destination.
Since most pickups were made within range of a surgical, field, or evacuationhospital, the ambulances usually overflew the battalion aid stations anddivision clearing stations, which could offer only basic emergency treatmentthat was already available on the helicopter, and deposited the patientsat a facility that offered definitive resuscitative treatment. Althoughthe less serious patients often found themselves overevacuated, the practicesaved thousands of patients who demanded immediate life-saving surgery.
The effective functioning of an air ambulance depended heavily on itsbank of four radios: FM, UHF, VHF, and single sideband (high frequency).The FM radio contained the frequencies of the Dust Off operations center,the tactical combat unit, and most hospitals. VHF and UHF were infrequentlyused. And the single sideband contained the medical regulating frequencies.The ambulance would
usually stay on its Dust Off frequency for flight following until heapproached the pickup zone, when it would switch over to the tactical frequencyof the unit with the casualties. After the pickup the ambulance would switchbriefly to the frequency of the forward medical regulator, which was closelymonitored by his group medical regulating officer. Then the ambulance wouldswitch back to the Dust Off frequency for flight following until it approachedthe hospital, when it would switch to the hospital's frequency, usuallyon the FM radio, to warn the doctors of the approach.
Although most of these procedures for area support missions also appliedfor direct support missions, there were a few important differences. Earlyin the war the 57th and 82d Medical Detachments, under the operationalcontrol of aviation battalions in the Delta, flew many such missions. Thebattalions would warn the detachments of planned airmobile operations andtheir requirements for aeromedical support. During a combat insertion,one or more Dust Off ships orbited near the landing zones at two or threethousand feet, out of effective small arms range, with the pilots monitoringthe helicopter- to- ground talk on the FM band, helicopter gunship talkon UHF, and any airplane- to- gunship talk on VHF. If a patient pickupbecame necessary during a ground fight, the command- and-control helicopterof the flight would designate two gunships to accompany the Dust Off shipinto and out of the area. The gunships would switch over to the Dust Offfrequency and make a slow pass over the area to draw fire, find the source,and suppress it. Then Dust Off would go in covered by the gunships. Laterin the war organic air ambulances sometimes accompanied the flight of transporthelicopters into the landing zones, and stood by waiting for casualties.More often they orbited the area of operations or stood by at the nearestbattalion or divisional clearing station. While affording excellent aeromedicalcoverage for the supported unit, direct support missions limited the abilityof the air am-bulances to respond to emergencies elsewhere.
All helicopter pilots in Vietnam had to cope with problems for whichthey might be unprepared or poorly equipped. By the nature of their work,air ambulance pilots experienced such problems more often than transportand gunship pilots. Except for the Medevac helicopters of the 1st CavalryDivision, the air ambulances carried no armament heavier than the pilots'M16 rifles, and most of the air ambulance missions were executed by a singleship rather than a well-prepared team, known as a "gaggle." Soldierswere shot and injured without regard to the terrain or weather, and theair ambulances were
expected to make their way to the casualties as soon as possible. Thepoor navigation equipment on the Hueys and the shortage of instrument-trained pilots early in the war exacerbated the difficulty of coping withSouth Vietnam's weather. While maintenance problems. plagued all the helicoptercrews in South Vietnam, the special demands of air ambulance work, suchas hoist missions, compounded the problems. Speed was important to inboundas well as outbound flights, making stops for refueling a dangerous luxury.While few of these problems could be totally solved, the air ambulanceunits often found ways to minimize them. When refueling during a missioncould not be avoided, the unit often called ahead to an established fueldepot and made an appointment for refueling at an en route landing strip.When a unit was jointly based with a gunship battalion, arrangements couldsometimes be made for an armed escort, especially on a hoist mission.
One of the problems that persisted throughout the war was the expectationthat the air ambulances would transport the dead. Nothing in USARV regulationsauthorized the ambulances to carry the dead; but both ARVN and Americansoldiers expected this service. Nonmedical transport helicopters and gunshipsoften evacuated both the dead and the wounded. If Dust Off ships had routinelyrefused to carry the dead even when they had extra cargo space, the combatunits might have decided to rely exclusively on their transports and gunshipsto evacuate both the wounded and the dead, resulting in a marked declinein the care provided the wounded. Combat operations might also have suffered,for ARVN soldiers often would not advance until their dead had been evacuated.So most air ambulance units practiced carrying the dead if it did not jeopardizethe life or limb of the wounded.
The language barrier also hampered the work of the air ambulance crews.Almost one-half the sick and wounded transported by the air ambulancescould not speak English, and the crews usually could not speak enough Vietnamese,Korean, or Thai to communicate with their passengers. Early in the warUSARV regulations prohibited a response to an evacuation request unlessan English-speaking person were at the pickup site to help the air ambulancecrew make its approach and evaluate the patients needs, or unless the requestingunit supplied the air ambulance an interpreter. But the scarcity of goodinterpreters in the South Vietnamese Army meant that Dust Off evacuatedmany Vietnamese whose needs were only vaguely understood. Even when theair ambulance unit shared a base with an ARVN unit, the language problemproved serious. A former commander of the 254th Detachment remembered suchan experience:
The periodic attacks on the airfield were experiencesto behold. Trying to get
from our quarters to the airfield was the most dangerous.The Vietnamese soldiers responsible for airfield security didn't speakEnglish and with all the activity in the night-vehicles driving wildlyabout, people on the move, machine gun fire and mortar flares creatingweird lighting and shadows - the guards were confused as to who shouldbe allowed to enter the field and who, had no reason to enter. If one couldget to the field before the road barriers and automatic weapons were inplace all was well. Later than that, one might just as well not even tryto get on the field. We had several instances of the guards turning ourofficers back at gunpoint! We tried to get ID cards made but the Vietnameserefused to issue any cards. We sometimes felt we were in more danger tryingto get to the airfield during alerts than we were picking up casualties.
The pilots and crews also had to contend with the ever-present dangerof a serious accident. Until later in the war most of the pilots lackedthe instrument skills needed to cope with the poor visibility typical ofnight missions and weather missions. The DECCA navigation system installedin the UH-IB's and UH-ID's proved virtually useless early in the war. Morepilots died from night- and weather-induced accidents than from enemy fire.
To cope with this danger, most of the pilots new to Vietnam quicklylearned the virtue of a cool head and even a sense of humor. One formercommander of a unit recalled the day that his alert crew at Qui Nhon receiveda request for the urgent evacuation of an American adviser who had falleninto a punji trap. (Such traps held sharpened wood stakes driven into theground with the pointed ends facing up, often covered with feces, ontowhich the victims would step or fall.) It was late afternoon, approachingdusk, but Maj. William Ballinger and his pilot scrambled on the emergencycall. They flew down the coast then turned inland to the pickup point.The casualty turned out to be a Vietnamese lieutenant with no more thana rash. Since they were already there, the crew picked him up and startedback to Qui Nhon.
On the way down the weather had turned bad, and when they headed northrain began. Night fell and the rain grew worse. Wondering whether theyshould set down or continue, they called the Qui Nhon tower operator andasked for the local weather. The operator reported a 3,000 foot ceilingand five miles visibility. The pilots thought they were in the middle ofan isolated storm and they expected to break out shortly. After flyingon and still not clearing the storm, they radioed the tower again and gotthe same report. Now their visibility was so bad they had to drop low andfly slowly up the beach. As they passed a point they knew to be only fivemiles from Qui Nhon, with the rain still pelting down, they again radioedthe tower operator and got the same report: ceiling, 3,000 feet and fivemiles visibility. Ballinger asked for the source of the weather report,
and the operator replied, "This is the official Saigon forecastfor Qui Nhon." Ballinger told the man to look outside the tower andthen tell him what the weather was. The operator replied, "Oh, sir,you can't see a damned thing out there." The pilots had to fly lowand slow to the base and were relieved when their skids touched the runway.Only then could they indulge in a good laugh.
Night missions quickly became a major problem in themselves. The difficultiesof such missions in a rural society were obvious: roads and populationcenters rarely were well lighted enough to aid in navigation to a pickupzone; terrain, especially in mountainous areas, became a great danger toambulances that lacked adequate navigation instruments; and adequate lightingat the pickup zone rarely existed. In the dry season a landing light reflectingoff the dust thrown up by the rotorwash could quickly blind a pilot justbefore touchdown. Throughout the war a considerable number of pilots andcommanders refused to fly night missions or else flew them only for urgentcases. Others, however, thought that night flying offered many advantagesthat at least compensated for its problems. A few, such as Patrick Brady,even preferred night missions.
Early in the war the 57th Detachment routinely flew night evacuations,so much so that at one staff meeting General Stilwell, the Support Groupcommander, asked why the 57th could fly so well at night when few otherscould or would. He quickly learned that one of the aids used by the 57thwas the AN/APX-44 transponder, which allowed Air Force radar stations tofollow the aircraft at night or in bad weather and vector them to and froma pickup site. Early in 1964 General Stilwell charged the medical detachmentwith the task of conducting a test on the feasibility of making combatassault insertions at night. In the Plain of Reeds the pilots experimentedwith parachute flares, tested the available radio and navigation equipment,and concluded that although night missions were suitable for medical evacuationthey were not suitable for combat assaults.
Night missions called for a few specialized techniques. En route atnight to a pickup zone an air ambulance would fly with either its externalrotating beacon or position lights on. Once below 1,000 feet on its approachto the zone, it would douse these lights and dim its interior instrumentpanel lights as soon as the ship drew within range of enemy fire. Aboutfive hundred feet from the touchdown, the pilot would briefly turn on hislanding light to get a quick look at the pickup zone. Then he would dousethe landing light until the last 200 feet of the approach. In an articlein Army Aviation Digest, Capt. Patrick Brady recommended a finaldescent at right angles to the ground unit's signal, since a pilot couldsee much better through the open side window than through the windshield,especially one covered with bulletproof Plexiglas. On the ground the soldierswould
use flashlights, small strobe lights, or vehicle headlights to markthe pickup zone. Some lights, such as flares, burning oil cans, and spotlights,tended to blind the pilot on final approach. A pilot in contact with soldierson the ground would try to warn them of this early enough to allow a changeof lights if necessary. On takeoff the lighting sequence on the ambulancewould be reversed.
While night magnified the dangers of weather and terrain, Captain Bradycorrectly noted that it reduced the danger of enemy fire. Although theenemy would always hear the approach of the noisy Huey, he could rarelysee it in the dark. An exhaust flame or the moonlight would sometimes betraya blacked-out aircraft, but the enemy could rarely direct accurate fireat the ship. Only night hoist missions allowed the enemy to get an accuratefix on an air ambulance, and the extreme hazards of hovering an aircraftclose to ground obstacles at night made even the best air ambulance pilotsavoid such missions unless a patient were in imminent danger of loss oflife.
A scarcely less dangerous form of night mission, a night pickup in themountains in bad weather, was also beyond the capacity of most air ambulancepilots. Brady, however, developed a technique for such a mission that madeit feasible if not safe for a highly competent pilot. One night in thefall of 1967, in Brady's second tour in Vietnam, his unit, the 54th Detachmentat Chu Lai, received a Dust Off request from a 101st Airborne Divisionpatrol with many casualties in the mountains to the west. Heavy rains andfog covered the area, and after a few attempts Brady decided that he wouldnever get to the casualties by trying to fly out beneath the weather. Hewould have to come down through the fog and rain with the mountains surroundinghim. He took his aircraft up to 4,500 feet and vectored out to the mountainson instruments. As he approached the mountains he took his ship up to 7,000feet. From his FM homing device he knew when he was directly over the pickupsite. Then he radioed an Air Force flare ship in the area and asked itspilot to meet him high above the pickup zone and foul weather below. TheAir Force pilot agreed and at Brady's suggestion took his plane to 9,000feet directly overhead and began to drop basketball-size parachute flares,larger and brighter than the Army's mortar and artillery flares. Bradypicked one out and started to circle it with his ship, dropping lower andlower into the fog, rain, and mist. The flare's brilliant light reflectingoff the fog and rain wrapped the Dust Off ship in a ball of luminous haze.Brady dropped still lower, gazing out of his open side window, alert forthe silhouette of crags and peaks. Suddenly the ship broke through theclouds. Brady recognized the signal lights of the unit below him, and settledhis ship onto the side of the mountain. He picked up the casualties andtook off. Now that he was under the clouds he could see better, and hemanaged to fly back to Chu Lai at low level. Back at
the base the rain was so heavy he could hardly see to land. While thepatients were being unloaded, and the ship readied for a second trip outto the mountains, the 54th's commander, Lt. Col. Robert D. McWilliam, wentout to Brady's ship and through the left window and asked the copilot howit was going. The young lieutenant just shook his head and said he couldn'tbelieve it. Knowing that the man was gung-ho, McWilliam thought he wouldnot leave the ship until the mission was over. He asked him, "Wouldyou like me to take over for you?" Instantly the man was out of theaircraft, and McWilliam took his place.
As he and Brady flew back to the mountains, the ground controller vectoredthem into the middle of the thunderstorm. Lightning flashed around them,but Brady flew on to the pickup site, where he again managed to get downthrough the clouds using the Air Force flares. But this time he could notfind the 101st patrol before the flares burnt out. Flying around in thedark only a few hundred feet off the valley floor, he and McWilliam strainedto see the signal light of the beleaguered unit. just as they saw it, anenemy .50-caliber machine gun opened fire on them. Brady jerked his craftaround to avoid the fire, and he and McWilliam lost the signal. Havinglost the enemy fire as well, they circled for several minutes trying tofind the signal again Suddenly the .50-caliber opened up at them again,and Brady knew that the U.S. forces had to be near. He managed to stayin the area this time, and soon the signal light flashed again. The DustOff ship landed and flew out more casualties.
Dust Off pilots often used Army artillery flares to light their pickupzone. But Major Brady had performed a far from standard night mission,using Air Force flares to descend through fog and rain in the mountains.In an article he wrote for Army Aviation Digest, Brady notedthat such a mission did have its dangers, especially if the flares burnedout before the ship had broken through the clouds. He wrote: "Nothingis more embarrassing than to find yourself in the clouds at 1,500 feetin 3,000-foot mountains and have the lights 90 out." The pilot's onlyrecourse then was to climb as steeply as possible; if he tried to maintainposition while waiting for another flare to come down, he ran the riskof drifting into the side of a mountain. Brady had demonstrated two qualities-imaginationand courage-that helped many Dust Off pilots cope with the challenges ofcombat aeromedical evacuation.
Although pilot error and mechanical failure accounted for more aircraftand crew losses in Vietnam than enemy fire, the air ambulance pilots worriedmore about the latter danger than the other
more controllable ones. Once the buildup got under way in 1965, anyair ambulance pilot who served a full, one-year tour could expect to havehis aircraft hit by the enemy at least once. When hoist missions becamea routine part of air ambulance work in late 1966, enemy fire became especiallydangerous. Although the pilots devised ways of reducing the danger, suchefforts barely kept pace with improvements in enemy weaponry and marksmanship.
Before the buildup began the pilots had little more than homemade weaponsto fear. In 1962 and 1963 the 57th Air Ambulance Detachment suffered lessfrom enemy fire than the nonmedical helicopter units, partly because ofthe limited number of missions the unit flew in this period. The unit'sfive ambulance helicopters flew a total of only 2,800 hours those two years,and no pilot or crewman was wounded or killed in action. To get their minimumflight time and provide themselves some insurance against a lucky enemyhit, the pilots started flying two ships on each mission. But once thebuildup got under way in late 1964 the unit went back to single ship missions,and most of the division and nondivisional air ambulance units that laterjoined them also followed this practice.
The return to single-ship missions demanded a few unorthodox procedures.International custom and the Geneva Conventions, which the United Statesconsidered itself bound to observe, dictated that an ambulance not carryarms or ammunition and not engage in combat. But in Vietnam the frequentenemy fire at air ambulances marked with red crosses made this policy unrealistic.Early in the war the crews started taking along .45-caliber pistols, M14rifles, and sometimes M79 grenade launchers. The ground crews installedextra armor plating on the backs and sides of the pilots' seats. The hoistmissions, introduced in the late fall of 1966, produced a high rate ofaircraft losses and crewmember casualties. Although at this stage of thewar gunship escorts for air ambulance missions were still hard to arrange,only the Air Ambulance Platoon of the 1st Cavalry responded to the newdanger by putting machine guns on their aircraft. At first the unit simplysuspended two M60's on straps from the roof over the cargo doors. Laterthey installed fixed mechanical mountings for the guns. A platoon aircraftalso usually carried a gunner as a fifth crewmember to handle one of theM60's. Later in the war many of the air ambulance units, both divisionaland nondivisional, tried to arrange gunship escorts, especially for hoistmissions, to pickup zones that had been called in as insecure. Throughoutthe war, however, such escorts proved hard to obtain, because aeromedicalevacuation was always a secondary mission for a gunship in a combat zone.
None of these defensive measures reduced the rate of air ambulance lossesin the war; they only prevented it from approaching a prohibitive level.Most of the Viet Cong and North Vietnamese
soldiers clearly considered the air ambulances just another target.A Viet Cong document captured in early 1964 describing U.S. helicoptersread: "The type used to transport commanders or casualties looks likea ladle. Lead this type aircraft I times its length when in flight. Itis good to fire at the engine section when it is hovering or landing."Fortunately Viet Cong weapons early in the war made a helicopter kill virtuallyimpossible. Late in 1964, however, the North Vietnamese began to supplythe Viet Cong with large amounts of sophisticated firearms: Chinese Communistcopies of the Soviet AK47 assault rifle, the SKS semiautomatic carbine,and the RPD light machine gun. The introduction of these new enemy weaponsin 1965-66 and of the hoist missions in late 1966 caused a dramatic increasein 1967 in the rate of enemy hits on air ambulances. Only in April 1972,however, when the United States was well along in turning the war overto the South Vietnamese, did the air ambulance have to contend with theSoviet SA-7 heat-seeking missile. This antiaircraft device was about fivefeet long, weighed thirty-three pounds, and had a range of almost six miles.A pilot had little warning of the missile's approach other than a quickglimpse of its white vapor trail just before it separated the tail boomfrom his aircraft. This weapon downed several air ambulances in the lastyear of U.S. participation in the war.
The missile also disrupted the most elaborate effort the Army made duringthe war to reduce the losses of air ambulances: a change of their color.The 1949 Geneva Conventions did not require that air ambulances be paintedwhite, and for their first nine years in Vietnam the Army's air ambulanceswere the standard olive drab, medically marked only by red crosses on smallwhite background squares. Early in the war many of the pilots thought thatthe crosses improved the enemy's aim at their ships, and the unit commandershad to resist pressure to remove the markings. Arguing that they wouldbe unable to keep aircraft that looked like transports dedicated to a medicalmission, the commanders prevailed, and the red crosses remained for therest of the war.
By mid-1971, however, the high loss rate for air ambulances over thelast six years produced much doubt about the olive drab color scheme. Believingthat making the aircraft more distinctive might be the answer, the ArmyMedical Command in Vietnam secured approval. in August to paint some ofits aircraft white. The Command also was allowed to try to persuade theenemy that the white helicopters were for medical use only and should notbe fired on. Thousands of posters were to be distributed and millions ofleaflets dropped over enemy-held territory. The most elaborate leafletread:
Some new medical helicopters not only have Red Cross markings on allsides but they also are painted white instead of green. This is to helpyou recognize them
better than before in order to give the wounded a better chance to getfast medical help. Like all other medical helicopters, these new whitehelicopters are not armed, do not carry ammunition, and their only missionis to save endangered lives without distinction as to civilians or soldiers,friend or foe.
MEDICAL HELICOPTERS ARE USED FOR RESCUE MISSIONS AND THEY ARE NOT ENGAGEDIN COMBAT. YOU SHOULD NOT FIRE AT THEM.
An enemy soldier still intent on bringing down any U.S. helicopter wouldnow find the white helicopters excellent targets against a background offorests, hills, or mountains. All armaments now had to be removed fromthe ambulances, and gunship escorts could no longer furnish close support.Unless the information campaign were successful, the air ambulances wouldencounter more rather than less resistance. But the risk, while undeniable,seemed justifiable in view of combat loss statistics: from January 1970through April 1971 the air ambulance combat loss rate was about 2.5 timesas great as that for all Army helicopters. Something had to be done.
The test program for white helicopters, begun on 1 October 1971, soonproduced encouraging preliminary results. In November the Army medicalcommand received permission to paint all of its remaining fifty air ambulanceswhite. However, the drawdown of U.S. forces was now in full swing. Thetest, which terminated the following April, had begun too late in the conflictand with too few helicopters to produce conclusive results. The white helicoptersat least had not proven any more dangerous than those painted olive drab.On 28 April 1972 the MACV Surgeon recommended to the Surgeon General thatwhite helicopters continue to be used for medical evacuation by the dwindlingnumber of Army units in Vietnam.
But in the same month the enemy's introduction of the heat-seeking SA7missile to South Vietnam put Army medical planners in a new quandary. Tonavigate properly, most air ambulance pilots could not fly to and froma pickup zone at altitudes low enough to enable the enemy on the groundto discern the white color and the red crosses. Except at the pickup zone,the white ambulances were as vulnerable as any other Army olive drab aircraft.Between 1 July 1972 and 8 January 1973 the enemy fired eight heat-seekingmissiles at white air ambulances. The only protection against the SA7 wasa new paint that reflected little of the engine's infrared radiation butdried to a dull charcoal green. In January 1973 USARV/MACV Support Commanddirected that all U.S. Army air ambulances in Vietnam be painted with thenew protective paint. Research began on a white protective paint, but beforeany significant progress could be made the war ended.
A Turning Point
By early 1968 the basic techniques of aeromedical evacuation developedduring the Vietnam War had been perfected. The helicopters, rescue equipment,and operating procedures were now ready for a full test of their utility.Their first trial came in February 1968 when the enemy launched a coordinatedassault on allied bases and population centers throughout the country.With little warning the Dust Off system had to cope with thousands of casualtiesin all four Corps Zones. The enemy offensive resulted in more helicopterambulances being shipped to South Vietnam, and by January 1969 the systemwas only one platoon short of its peak strength. That year Dust Off carriedmore patients than in any other year of the war. Although the fightingthen began to wane for U.S. forces, the Dust Off system still had to facetwo more ordeals: large operations in Cambodia and Laos. The final yearsof Dust Off in Vietnam proved to be the most difficult, and they earnedhelicopter evacuation a lasting place in modern medical technology.