CHAPTER VII
Aviation Medicine
Approximately two-thirds of the Army aviation resources supporting operationsin Vietnam were assigned to the units of the 1st Aviation Brigade. Theremaining aircraft and men were assigned to those units organic to thedivisions; relatively few were assigned to artillery, engineer, aircraftmaintenance, signal, or other support units. Although the strength of the lstAviation Brigade was not much greater than 25,000 men, its approximately 50flight surgeons provided primary medical care on an area basis to more than35,000 troops. In some areas, the dispensaries of the 1st Aviation Brigade werethe only source of outpatient care. The medical units of the brigade establishedliaison and close working relationships with their nearest supporting hospitals,referring patients for consultations, inpatient care, and specialized treatment.
The flight surgeon is a physician who has received formal training in thespecialized field of aviation medicine. His mission includes the prevention andtreatment of disease, injury, and mental or emotional deterioration amongaviation flight, ground crew, and maintenance personnel. He monitors theprograms of flyers and is expected to participate in frequent flights. He isconfronted by the problems of traumatic injury; of acute and chronic disease,ranging from the common upper respiratory infections to the most uncommon oftropical diseases; of psychiatric disorders, which run the gamut fromoccupational fatigue through the minor disorders of personality to overtpsychoses; and of personal hygiene and environmental sanitation, includingdietetics, venereal disease, insect control, and a multitude of bizarre andhomely worrisome matters. The flight surgeon treats physical and mentalconditions that might endanger pilots or passengers. Whether in the examinationroom or upon the flight line, he must be able readily to detect incipient majorand minor disorders of personality in men who, in their zeal to fly, frequentlytry to conceal the disorders. He administers and prescribes medications andtreatment, and he reviews and studies the case history and the progress of thepatient. He also acts as consultant in his specialty to other medical servicesand provides aeromedical staff advice. In addition, the flight surgeon serves asmedical member of aircraft crash investigation teams and, when possible,contributes to aeromedical research and development.
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The number of flight surgeons authorized in Vietnam reached a maximum of 86in August 1968; by November, 98 were actually assigned there. This maximumcontrasted with shortages during such periods as August 1967, when theseassignments fell to 40 percent below the authorized strength.
The flight surgeon, assigned to a unit of an aviation brigade, was supportedby a medical detachment team which provided dispensary service. These teams wereassigned generally on a basis of one detachment per two aviation companies. Theunit flight dispensary was usually located next to the airfield, often in a unitbilleting area, and the flight surgeon and his staff usually lived with thetroops that they served. This arrangement, allowing for optimum rapport andmedical services, was especially advantageous when the airfields were underattack, and it proved vital during the 1968 Tet Offensive, when many airfields were isolated.
Flyer Fatigue
The aeromedical problems that faced Army aviation units in Vietnam provideda challenge to their supporting flight surgeons. No problem, however, was morecommon yet more elusive than that of flyer fatigue. It became more pronouncedafter 1965 when the buildup of U.S. forces gained momentum and remained asignificant limiting factor in the conduct of airmobile operations. By the endof 1966, aviators were flying 100 to 150 hours or more per month, and the needto know how much an aviator could fly before he was so fatigued that he was nolonger effective or safe was evident.
Army aviators were assailed by a multitude of stresses, each to some extentcapable of endangering their missions. The stress from hostile fire wasaggravated by such factors as heat, dehydration, noise, vibration, blowing dust,hazardous weather, exhaust from engines and weapons, and labyrinthinestimulation. Additional stress was caused by psychic elements, such as fear,insufficient sleep, family separation, and frustration. These stresses, actingon the aviator day after day, combined with the physical exertion of long hoursof piloting an aircraft, caused fatigue.
The ever-increasing requirements during the years 1967-68 for aviationsupport caused the accrual of extremely high aviator flying times in all units.Night operations, with their extra demand upon the critical judgment of theaviator, increased. The shortage of crews often forced an individual to undertakeboth day and night missions without adequate rest.
In response to expressed concern of the unit commanders and of aviationsafety officers, flight surgeons at all levels of aeromedical support studiedevery aspect of the fatigue problem. Because fatigue was the result of manyvariables, it defied easy definition and precise measurement.
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Emphasis, therefore, was placed on prevention-eliminating or reducing thosefactors in the aviator's environment that caused stress.
General Neel, Surgeon, USARV, noted in the Command Health Report for August1968 that approximately 70 percent of aircraft accidents were found to be theresult of pilot error and that pilot fatigue had been implicated as acontributing factor in a large proportion of accidents. He indicated that theonly way to cope with pilot fatigue was prevention by reducing the aviator'sflying hours. His recommendation was "that immediate action be taken toprovide additional aviators to USARV insuring at least 100 percent authorizedaviator strength to reduce the degree to which pilot fatigue is contributing tothe loss of lives and expensive aircraft." This was never done.
The unit flight surgeon's close scrutiny of charts that showed each pilot'sflying hours for the previous 30 days, followed by close co-operation among theunit commander, platoon leaders, operations officer, noncommissioned officers,and flight surgeon, proved an invaluable system for collecting data on which theflight surgeon based his final recommendation to the commander. By the end of1968, this system was utilized by most of the aviation units.
Some flight surgeons, notably Captain Philip Snodgrass, MC, of the 269thAviation Battalion at Cu Chi, believed that the relationship of days flown todays off and, particularly, the provision of a scheduled "on-off" workcycle were more important than the total number of hours flown. CaptainSnodgrass's staff study of a "goal-directed" flying-hour scheduleindicated that a series of 5 or 6 days flown, followed by a scheduled day freefrom flying and from other duties, resulted in a unit that evidenced lessfatigue and could fly even greater numbers of hours. This idea was adopted bymany units and proved workable and effective.
Fatigue in the enlisted crew members was a less obvious, though very real,threat. These individuals, who accompanied the aircraft on all its missions,returned to their base camps only to work many additional hours in providingrequired maintenance and preparing for the following day's missions. With theadded requirement of aiding in perimeter defense and in the multitudinous otherdetails of combat aviation, they performed under great stress. Efforts by theunit flight surgeons in their behalf centered upon improving their livingconditions, eliminating some extra duties, and increasing their numbers.
By 1970, fatigue as an entity was still no better defined nor more capable ofmeasurement than before. Moreover, the attempt at limiting aviator flying hoursby regulation had been proved ineffective in the combat environment, and therequirement for continued study of the problem was evidently needed.
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Care of the Flyer Program
Flight Physicals
The problem of performing periodic physical examinations on flying personnelbegan with the first Army aviation unit in Vietnam. Equipment and facilitieswere not available for an adequate examination. This handicap was partiallyovercome by Department of the Army waiver of the requirement for routineperiodic examinations for rated aviators in Vietnam; however, despite thewaiver, many still requested them. Periodic examinations for crew chiefs, flightsurgeons, and aerial observers were also waived; required initial examinationswere performed as well as available equipment allowed. Modifications oforganization and the addition of equipment helped eliminate these difficulties.Aerial door gunners were not given a complete examination. After reviewing theirmedical records, the flight surgeon gave them a general examination whichincluded visual tests and their "Adaptability Rating for MilitaryAeronautics." A statement of medical qualification was then issued by theflight surgeon.
Waiver authority was retained by USARV headquarters for medical standards forpilots, crew chiefs, flight surgeons, and aerial observers. Headquarters policyon standards for pilots was strict. Policy on standards for others who wereexpected to participate in aerial flights was considerably more lenient;conditions were waived if they were not dangerous to the individual's health andwould not interfere with mission completion.
Significant Medical Conditions
The incidence of infectious disease among aviation personnel in Vietnamgenerally paralleled that of other troops in the area. Many diseases, however,were more serious for flying personnel because of possible time lost fromprimary duties. Basic preventive medicine, therefore, was of prime importance tothe unit flight surgeon.
Diarrhea and upper respiratory infections were particularly costly in termsof aviator availability. Aviation companies normally operated a single mess and,on some occasions, were rendered ineffective for short periods because ofepidemic gastroenteritis. Food and ice procured from local handlers werefrequent sources of these outbreaks despite constant screening and surveillanceby the flight surgeon. Venereal diseases, notably gonorrhea, were ofparticularly high incidence.
Breakdowns in basic field medicine practices and water supply controloccurred. Individual soldiers were occasionally charged with the treatment ofwater without adequate knowledge of the techniques involved. Failure tomaintain adequate chlorine residual and even the
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accidental use of nonpotable supplies presented problems. In April 1968, inthe 1st Cavalry Division (Airmobile), thousands of cases of gastroenteritissevere enough to cause loss from duty occurred almost simultaneously, and manymore men were symptomatic without loss of duty. Investigation implicatedcontaminated water. The 164th Aviation Group, located in the Delta region withheadquarters at Can Tho, had outbreaks of hepatitis during the summers of 1967,1968, and 1969. Mass immunization with gamma globulin was required to abortthese episodes, some of which apparently originated from using nonpotable iceand frequenting Vietnamese food establishments.
Aircrews frequently encountered skin disorders, often miliarial or fungal inetiology. The long hours of flying while dressed in protective equipment and theintense dust clouds raised by helicopter operations contributed to the adversedermatological environment. External otitis sometimes caused restriction offlying duties.
Malaria was significant only sporadically. Basic mosquito control measureswere effective in secure base areas, and it was there that aircrews usuallyspent their evenings. The continuous presence of the aviation unit flightsurgeon with constant emphasis on preventive medicine techniques and healtheducation for the aviator undoubtedly contributed to the low incidence.
Medication and Therapy
Traditional aeromedical philosophy on the use of drugs by flying personnelis conservative. AR 40-501 and AR 40-8 specifically limit their use. The flightsurgeon's duty was to promote a state of individual fitness that allowed theflyer to meet the myriad stresses of combat flying. Ideally, the use of systemictherapeutic agents should have been prohibited in Vietnam, as they areelsewhere, but realistically, the unit commander needed the maximum number ofpersonnel to carry out his mission. It was the duty of the flight surgeons toevaluate the risk of using therapeutic and prophylactic agents against theimpact of losing personnel to flying duties while undergoing treatment. On thisbasis, the flight surgeon frequently administered certain drugs withoutrestricting the aviator from flying, and other drugs after careful evaluation ofthe pilot's condition and his particular response to the drug. When the acutemedical condition of an aircrewman did not prohibit flying status, he was oftenallowed to fly after a period of drug use to determine his susceptibility toside effects. Antibiotics and decongestants were used but antihistaminics,sedatives, and tranquilizers were prohibited.
Aviation personnel had to take the weekly malaria chemoprophylactic tablet;those who exhibited significant side effects were evaluated by the
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unit flight surgeon and placed on chloroquine tablets if the reaction was dueto the primaquine component. Many aviation units required their men to take thechloroquine-primaquine tablet on Monday night rather than on Monday morningbecause of the diarrhea that sometimes occurred shortly after ingestion. Theincidence of glucose-6-phosphate dehydrogenase deficiency was low.
Dapsone, when introduced in Vietnam, was used only where recommended by theappropriate medical authority; a very low incidence of methemoglobinemia wasevaluated in the 7/17th Air Cavalry Squadron by the unit flight surgeon and theWRAIR team in Saigon. The incidence of fungus infections prompted therapy withgriseofulvin in selected aviators, who continued to fly during long-termtreatment. Throughout the years of Army aviation operations in Vietnam, thepractical approach to the question of therapeutic agents turned out to beeffective.
Safety
Accidental injury was a source of significant personnel loss. Aircraftaccidents, until the spring of 1968, caused more aircrew injury and death thandid enemy action. Less spectacular but also significant were those casualtiescaused by weapons accidents, vehicle mishaps, and sports. Relatively simpleinjuries removed the patients from flying duties for the duration of treatment.
All flight surgeons participated in the flight safety program at all levelsof command. In addition to their constant fatigue monitoring and their vigilantprotection of the mental, emotional, and physical health of all aircrews, theyserved as advisers in evaluating and proposing protective armor for bothaircraft and aircrew.
Aircrew Wound Experience
The vulnerability of the helicopter when used as a tactical aircraft isextremely serious. The ways in which the vulnerability of the crew may bereduced is a significant matter. During 1965 and 1966, studies were made on theeffectiveness of armor for both men and equipment. Although helicopter crashesfrequently were caused by enemy fire, evidence existed that few were the resultof injury to the pilot. By the end of 1965, crashes had caused 101 fatal and 79nonfatal injuries, and "missiles and shells" had caused 43 fatal and673 nonfatal wounds. Effectiveness of seat armor was implicit in the notation"most fatalities due to wounds of head, throat, and upper torso."
Medical input requested by the 1966 Army Materiel Command study group for astudy in Vietnam was provided by representatives of
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USAMRDC (U.S. Army Medical Research and Development Command).
In April 1966, Captain James W. Ralph, MC, produced a staff study on aviationcasualty reporting for the Army Concept Team in Vietnam in an attempt todetermine whether or not the data being compiled was being analyzed and could beapplied to studies of protective equipment. With the collaboration of Major(later Colonel) James E. Hertzog, MC, Surgeon, 1st Aviation Brigade, andAviation Medicine Consultant, USARV, a form was developed for reporting wounds.
In June 1966, USARV Regulation 40-42, "Wound Evaluation andAnalysis," was published, requiring that specific data be reported on allcrewmembers wounded in Vietnam, and placing the responsibility forimplementation upon the unit flight surgeon. By early 1967, only a small percentof wound incidence had been reported because of communication and transportationdifficulties. The number and locations of the medical facilities hindered theflight surgeons' interviewing and recording the pertinent data on every woundedaircrewman. Late in the year, the regulation was amended to provide forreporting by the commander of the medical facility receiving an injuredaircrewman; the amendment resulted only in total failure of the reportingsystem. Although the amount of wound data reported by flight surgeons in 1966was meager, the available information showed that both personnel armor andaircraft armor were of great protective value.
Life Support Equipment
At the onset of Army aviation operations in Vietnam, crewmembers flew theirsupport missions in H-21 aircraft, dressed in fatigues or U.S. Air Force issuecoveralls, leather gloves, and 1959 model APH-5 flight helmets. With theexception of occasional flak jackets of Korean War vintage, any additionalprotection was provided by makeshift means. The aircraft were not armored andwere relatively vulnerable to enemy fire. In general, survival kits were alsomakeshift. The need for measures to increase the survivability of aircrewmembers was evident.
In 1962, the Army Materiel Command initiated a long-term research anddevelopment project to reduce the vulnerability of Army aircraft and aircrew.The results of this project and the related efforts of other commands, such asUSAMRDC, provided much of the equipment lacking in those early years. Flightsurgeons in the field provided impetus to this development effort.
While crash-injury fatalities in aircraft hit by ground fire were three timesthose caused by bullet wounds, the need for protection from small arms fire wasrecognized through work done by the U.S. Army Ballistic Research Laboratories.By 1965, the H-21 helicopters had been phased
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out of Vietnam, and all UH-l aircraft were equipped with armored seats forthe pilot and copilot. Unfortunately, the great need for an armored seat for thegunner and crew chief on UH-1 aircraft was never met in the field, althoughdevelopment was undertaken.
Body armor of bullet-protective plates in a canvas carrier was introduced in1965 for protection of the torso. It was widely accepted by aircrews. The pilotand copilot of the aircraft utilized the chest protection only, since they wereotherwise protected by the armored seat. Body armor containing both front andback protective plates was worn by other crewmen of the aircraft. There are manydocumented cases of individuals sustaining direct hits on these protectiveplates without injury other than bruises.
In January 1966, the Department of the Army approved a project for thedevelopment of flight clothing which would provide fire protection, becompatible with cockpit design, and resemble the uniform worn by the footsoldier. Deliveries to Vietnam of a two-piece Nomex uniform began early in 1968,and by year's end adequate quantities were on hand to meet all requirements. In1969, the fire-resistant flight uniform, having been well received by aircrews,was made Standard A for the Army.
Individually carried survival kits were considered necessary by most flightsurgeons and aircrewmen in Vietnam early in the war. A variety of survival kitswere developed and made available in quantity. However, as experienceaccumulated in Vietnam, it was noted that survival kits were seldom utilized bythe survivors of downed aircraft. Few persons were rescued if downed in hostileterritory more than a few hours. The consensus of flight surgeons and otheraeromedical personnel was that items of signal equipment were most valuable. Thesurvival radio, if working, appeared to be the most important item in thelocation and rescue of downed aircrewmen. Recognition of this fact led toemphasis upon the continuing development of more reliable survival radio sets.
Before 1961, flight surgeons had cited the need for better head protection,including fragmentation protection. Early in 1967, after more than 6 years ofdevelopment, the AFH-l helmet, which met specifications, was delivered toaviation units but proved to be too small for many of the aircrewmen. Major(later Lieutenant Colonel) Anthony A. Bezreh, MC, who, as aviation medicineconsultant and 1st Aviation Brigade surgeon, had provided primary impetus to theimprovement of items of safety equipment, reported the results of a survey doneon this helmet. Later attempts at modifying it were largely unsuccessful, anduntil 1969, aircrews were wearing a mixture of APH-5 and AFH-1 helmets.
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In 1969, a new flight helmet, the SPH-4, incorporating markedly improvedretention and noise attenuation qualities, was procured for use in Vietnam andreceived immediate acceptance in the field. It proved effective in theprevention of injuries and became Standard A early in 1970.
