飞行员地面错觉模拟及其反应参考值

目的 验证地面错觉训练方案在我军飞行员航空医学训练中应用的可行性,为评价地面错觉模拟训练效果提供参考值.方法 在我军现有错觉模拟训练方案基础上,参照北大西洋公约组织推荐的地面错觉模拟训练方案,依据现有的设备,对80名健康飞行员进行地面错觉模拟训练.在VTS-0型电动转椅上进行躯体旋动错觉、科里奥利错觉模拟,在VTS-Ⅲ型前庭功能检查系统上进行相对运动性错觉、自动性错觉模拟,观察错觉的诱发情况,并进行相应错觉反应参数（错觉持续时间、潜伏期）的记录.结果 躯体旋动错觉、科里奥利错觉、相对运动性错觉和自动性错觉的诱发率分别为100.0%、90.7%、72.5%和49.2%.前庭性错觉的诱发率要大于视性错觉（χ2=5.01,P〈0.05）.飞行员躯体旋动错觉、科里奥利翻转错觉、科里奥利滚转错觉的持续时间分别为（8.4±4.5）s、（4.9±2.3） s、（5.4±3.0） s;相对运动性错觉、自动性错觉的潜伏期分别为（34.8±19.0） s、（42.8±15.2） s.5种错觉反应数据的参考值分别为：躯体旋动错觉持续时间≤17.4 s,科里奥利滚转错觉持续时间≤11.4 s,科里奥利翻转错觉持续时间为0.3～9.5 s,相对运动性错觉潜伏期≤72.8 s,自动性错觉潜伏期为12.4～73.2 s.结论 立足现有训练装备,我军飞行员躯体旋动错觉、科里奥利错觉、相对运动性错觉及自动性错觉的地面模拟训练方案是有效的、可行的.5种错觉反应数据的参考值可望为飞行员地面错觉模拟效果评价提供依据.     

Hearing in military pilots: one-time audiometry in pilots of fighters, transports, and helicopters

INTRODUCTION: Pilots are exposed to potentially harmful levels of noise, the actual consequences of which are still poorly documented. We have determined the audiometric profiles of pilots as a function of age and type of aircraft (i.e., fighter, transport, helicopter) and have searched for risk factors of deafness other than noise in a pilot population. METHODS: We examined 521 French military pilots ages 20-40 yr during their annual medical check-ups. Pilots were interviewed using a standardized questionnaire and data from tonal audiograms of both ears were collected. Hearing levels were compared between groups of age and aircraft category. RESULTS: Abnormal hearing levels in pilots were found essentially at high frequencies with a marked notch on audiograms at 6 kHz. Left ears had a significantly poorer performance compared with right ears. At a given age, transport pilots had, on average, better hearing at 8 kHz than other pilots, despite a higher number of flying hours. In addition to the 6 kHz notch, helicopter pilots showed a significant hearing loss at 3 kHz. Such an enlargement of the impaired frequency range can disturb speech communication. Prevalence of otitis media in childhood was significantly higher in pilots with abnormal hearing. DISCUSSION: Pilots flying fighter and helicopter aircraft are at a higher risk of hearing loss compared with pilots flying transport aircraft. Improvements in ear protection seem particularly needed for the left ear. Hearing losses can potentially compromise speech communication in helicopter pilots.     

Systolic blood pressure in fighter pilots after 12-15 years service

Systolic blood pressure (SBP) was measured at entry and after 12-15 years in 112 fighter pilots and compared to 112 transport and helicopter pilots. The pilots were 20-24 years old on entry into the study. Mean SBP +/- 1 S.D. on entry was 122 +/- 12 mm Hg in fighter pilots and 124 +/- 12 mm Hg in transport and helicopter pilots. After 12-15 years follow-up the mean SBP was 118 +/- 12 mm Hg in both groups. We conclude that the stress of flying fighter aircraft for 12-15 years is not associated with an increased risk of hypertension.     

空军飞行员飞行错觉后反应分析

目的 掌握现阶段空军飞行员发生飞行错觉后反应状况,以期制定相应对策. 方法 运用"飞行错觉水平量表"对来院疗养的1275名空军飞行员进行飞行错觉问卷调查. 结果 有效量表1221份,飞行错觉总发生率为91.5%,发生错觉后看仪表不能克服的占8.1%,发生错觉后影响操纵的占32.7%,发生了错觉不知道的占6.9%,发生错觉后不能识别周围环境的占1.4%,出现不适症状的占56.6%.歼击机、强击机飞行员飞行错觉后的反应水平明显高于其他机种(P＜0.05).结论 空军飞行员飞行错觉后反应影响飞行安全,急待建立飞行错觉系统训练体系,减少飞行错觉后反应发生,降低飞行错觉反应水平. Abstract： Objective To investigate the Air Force pilots' response to the flight illusion for finding countermeasures. Methods A questionnaire entitled" the level scale of flight illusion" was inquired from 1275 pilots. Results The incidence of flight illusion was 91. 5% by analyzing 1221applicable replies. Among which even 8. 1% pilots could not overcome the illusions by observing instruments. 32.7% pilots reported illusion caused difficulties on aircraft control while 6.9% and 1.4% pilots respectively showed unawareness of illusion and lost the awareness of environment when illusion happened. 56. 6% pilots appeared discomfort. Fighter and attacker pilots showed stronger response than the other type of aircrafts' (P＜0.05). Conclusions Pilot's negative responses to flight illusions have effectively influenced flight safety. It is suggested to build up corresponding training system to control the pilot's negative response to flight illusions.     

Visual acuity, corrective lenses, and accidents in helicopter pilots

The visual acuity of 38 helicopter pilots experiencing serious air accidents was compared to that of a control group of 72 pilots, matched for age, aircraft, and hours of flight. Decrease in visual acuity was divided into two groups: 1) minor decreases in vision up to 20/25 (not requiring corrective lenses); and 2) visual acuity of 20/30 or less with correction to 20/20. Minor decreases in visual acuity were found in 23.7% (9/38) of those in the accident group compared to 25.0% (18/72) in the control group. There were more pilots in the control group who needed corrective lenses (12.5% (18/72) versus 2.8% (1/38), p less than 0.07). We conclude that helicopter pilots with corrective lenses or minor uncorrected decreases in visual acuity are not at increased risk for serious air accidents.     

Thoracolumbar pain among fighter pilots.

High +Gz forces place high stress on the spinal column, and fighter pilots flying high-performance fighter aircraft frequently] report work-related thoracic and lumbar spine pain. The aim of this study was to determine whether +Gz exposure causes work-related thoracolumbar spine pain among fighter pilots. A questionnaire was used to establish the occurrence of thoracic and lumbar spine pain during the preceding 12 months and during duties over the whole working career among 320 fighter pilots and 283 nonflying controls matched for age and sex. Thirty-two percent of the pilots and 19% of the controls had experienced pain in the thoracic spine during the preceding 12 months (odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.5-3.5; p = 0.002 for the pilots). Among the pilots, the OR increased up to 6.1 (95% CI = 1.6-23.1; p = 0.0007) with the number of +Gz flight hours. There was no difference between the groups with regard to lumbar pain during the preceding 12 months, but over their whole working careers fighter pilots (58%) had experienced lumbar pain during their duties more often than controls (48%) (OR = 1.8; 95% CI = 1.3-2.6; p = 0.002). The greater the number of +Gz flight hours, the greater the occurrence of lumbar spine pain when on duty (OR = 26.9; 95% CI = 6.2-116; p = 0.0001 for the most experienced fighter pilots). The same was not true with regard to the number of +Gz flight hours and lumbar pain during the preceding 12 months. Age had no effect on pain in the thoracic or lumbar spine. Fighter pilots flying high-performance aircraft have more work-related thoracic and lumbar spine pain than controls of the same age and sex. The difference is explained by the pilots' exposure to +Gz forces.     

不同机种飞行人员血糖水平分析

目的 了解不同机种飞行人员血糖水平情况并分析原因,为稳定飞行人员血糖水平和保证飞行安全提供依据. 方法 2011年1月至2013年8月来我院疗养的532名飞行人员.按年龄将飞行人员分为＜30岁、30～39岁、≥40岁3组;按飞行时间分为＜1 000 h、1 000～1 999 h、≥2 000 h 3组,对不同机种飞行人员FPG水平进行分析比较. 结果 ①飞行人员FPG平均水平为（4.55±0.54）mmol/L.不同年龄组、不同飞行时间组直升机飞行人员FPG水平差异均有统计学意义（F＝4.290、5.157,P＜0.05或0.01）.不同年龄组轰炸机飞行人员FPG水平差异有统计学意义（F＝4.582,P＜0.05）.其余机种飞行人员不同年龄组、不同飞行时间组之间FPG水平差异均无统计学意义（P＞0.05）.②＜30岁组的歼击机飞行员FPG水平明显高于直升机、轰炸机、预警机飞行人员（P＜0.01）;教练机飞行员FPG水平明显高于轰炸机、预警机飞行人员（P＜0.05）.30～39岁组歼击机、直升机、教练机飞行人员FPG水平均明显高于轰炸机飞行人员（P＜0.01）;直升机、教练机飞行人员FPG水平明显高于预警机飞行人员（P＜0.05）.≥40岁组,不同机种飞行人员FPG水平差异无统计学意义（P＞0.05）.③飞行时间＜1 000 h组歼击机飞行员FPG水平明显高于直升机、轰炸机和预警机飞行人员（F＝7.655,P＜0.01）.飞行时间1 000～1 999 h组歼击机、教练机飞行人员FPG水平明显高于轰炸机飞行人员（P＜0.01或0.05）;歼击机、直升机、教练机飞行人员FPG水平均明显高于预警机飞行人员（P＜0.05）.飞行时间≥2 000 h组歼击机、直升机、教练机飞行人员FPG水平均明显高于轰炸机飞行人员（P＜0.05或0.01）. 结论 不同机种飞行人员FPG水平存在不同程度差异,应予重视.     

Alcohol associated with fatal light aircraft accidents, United Kingdom-1964-1973.

A total of 86 fatal light aircraft accidents in the United Kingdom from January 1964 to December 1973 are reviewed, in which tissue alcohol determinations were undertaken on 102 pilots. Alcohol was detected in 34 cases varying from small amounts of 313 mg/100 ml. The difficulties of interpretation of post mortem tissue alcohol levels are discussed with particular reference to those cases with measured alcohols in excess of 20 mg/100 ml a level taken as possibly significant in context of accident causation. There was 12 pilots, involved in 10 of the 86 fatal accidents, considered as having ingested alcohol before flying, giving an incidence of 11.6% fatal light aircraft accidents with an alcohol involvement. Half of the pilot crashed within 18 min of takeoff, and half had less than 100 h flying experience. It is noted that five of the accidents occurred in 1973. Education of pilots to the hazards of alcohol and flying is the ultimate solution.     

G-induced visual and cognitive disturbances in a survey of 65 operational fighter pilots

INTRODUCTION: Only one previous study has assessed almost loss of consciousness (A-LOC) in operational fighter pilots, reporting an incidence rate of 14%. Research also indicates that 8-13% of pilots have experienced G-induced loss of consciousness (G-LOC). A-LOC can be as insidious as G-LOC due to the associated altered state of awareness and relative incapacitation time, making it a significant risk factor in the high +Gz environment. Royal Australian Air Force (RAAF) pilots currently fly the F/A-18 and Hawk 127, producing +Gz accelerations up to +7.5 Gz, which places these pilots at risk of both A-LOC and G-LOC. METHODS: A survey was administered to 100 active RAAF fighter pilots requesting information on G-induced visual and cognitive disturbances, A-LOC symptoms, and G-LOC. Details regarding type of aircraft, flying maneuvers performed and mission outcome were also sought. RESULTS: There were 65 RAAF fighter pilots who completed the survey (age 20-53 yr, height 168-193 cm, weight 64-110 kg, jet hours 30-5700 h). Of these pilots, 98% indicated they had experienced at least one visual or cognitive disturbance in the high G environment: gray-out 98%; black-out 29%; and A-LOC symptoms 52%, including abnormal sensation in limbs, disorientation, and confusion. There were 9% who indicated they had experienced G-LOC (50% were the pilot flying the aircraft). DISCUSSION: These findings indicate that RAAF fighter pilots are experiencing a similar rate of visual disturbances and G-LOC when compared with other air forces. However, RAAF pilots reported a much higher incidence of A-LOC compared with the only other study of operational fighter pilots.     

Analysis of changes in the pilot population and general aviation accidents.

General Aviation pilots have been involved in a steadily decreasing number of accidents over the past 20 years. Changes in the age distribution, certification, and flying habits of these pilots make direct comparison of accident statistics inaccurate. This study reviews changes in the pilot population over the past 20 years to analyze their impact on accident statistics. Pilot age and certificate distributions from 1968 to 1987 were assembled from annual Federal Aviation Administration (FAA) surveys. Information about pilots involved in accidents was collected from annual National Transportation Safety Board (NTSB) reports. Trends in pilot age distribution, certification, aircraft use, flight planning, and weather were reviewed. The accident experience from the first 5 years of the study period was used to construct an adjusted plot of expected aircraft accidents. From 1968-87, the mean pilot age increased from 35 to 40 years and the number of pilots over the age of 60 increased five-fold. The number of pilots with Air Transport Pilot (ATP) certification tripled and instrument certification increased 80%. Accidents where an Instrument Flight Rules (IFR) flight plan was filed increased from 3.6% to 6.6% without a corresponding increase in the number of accidents in weather at or below instrument meteorologic conditions (IMC). The accident experience from 1968 to 1973 predicted 116,000 accidents from 1968 to 1987. The actual number of accidents was 40% less than predicted. The average pilot age has increased both due to more pilots over the age of 50 and less young student pilots.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pilot-induced factors in fatal light aircraft accidents in the United Kingdom: 1969-1981

The author reviews 52 personally investigated fatal light aircraft accidents involving 8 professional pilots and 44 private pilots. In 22 of the 52 accidents the presence of any pre-crash defect or malfunction of airframe, engine, or flying controls was definitely excluded. In the opinion of the author there was a "pilot-induced" factor in 35 (69.3%) of the 52 fatal accidents. The author discusses the pilot-induced factors associated with some of these accidents and refers to some of the mechanical defects encountered.     

Cervical spine degeneration in fighter pilots and controls: a 5-yr follow-up study

At 5 yr after MRI of the cervical spine, for evaluation concerning degenerative lesions, follow-up MRI was performed on asymptomatic experienced military high performance aircraft pilots (mean age 47 yr; mean accumulated flying time 3,100 h) and on age-matched controls without military flying experience. Young military high performance aircraft pilots (mean age 28 yr, mean accumulated flying time 915 h) were also re-examined. Compared with baseline MRI 5 yr earlier, there was significant increase in disk protrusions in all groups, in osteophytes in controls, and in foraminal stenoses in experienced pilots, and a significant reduction in disk signal intensity in young pilots. The difference between experienced pilots and controls was markedly reduced compared with that at baseline MRI. Thus, military high performance aircraft pilots seem to be at increased risk of premature development of degenerative lesions of the same type as are seen in an aging population. With increasing age the difference between pilots and controls diminishes.     

Neck pain and related disability in helicopter pilots: A survey of prevalence and risk factors

INTRODUCTION: Today's demands on helicopter missions-often using helmet-mounted visual technology-place much physical stress on the cervical spine. The objective of the present analytical survey was to estimate the prevalence of, and associated risk factors for, helicopter pilots' neck pain and related disability. METHODS: There were 127 Swedish helicopter pilots consecutively enrolled for the study who completed a structured questionnaire during their regular medical health checkups. The questionnaire concerned flight-related and individual risk indicators, frequency of neck pain episodes, and disability. Multivariate regressions, with the potential to control for confounding factors, were used to estimate relative risks (RR). RESULTS: The 3-mo prevalence of neck pain was 57%, with 32% reporting frequent pain. A history of previous neck pain (RR = 1.8, 95% CI = 1.2-2.7) and recent shoulder pain (RR = 1.6, 95% CI = 1.1-2.4) were significant risk factors, while the use of night-vision goggles and muscle strength-training showed a non-significant associated trend, the latter toward a decreased risk. In neck pain cases, 58% and 55% reported that their pain interfered with their flying and leisure, respectively, and those with frequent pain risked pain interfering with flying duty (RR = 1.6, 95% CI = 1.1-2.5). However, only 25% of the cases had ever been on sick leave due to neck pain. CONCLUSIONS: Neck pain is common among helicopter pilots, and certain factors are identified for use in risk reduction. The link between cases with frequent pain and reported interference with flying duty highlights the need for early prevention of neck pain when planning and implementing helicopter pilots' health care. More clinical trials of good design are required.     

战斗机飞行员颈椎退变研究

目的 了解战斗机飞行人员颈椎退变情况。方法对5年前作过MRI检查的战斗机飞行员（甲组,平均年龄47岁,平均累计飞行时间2100h,乙组,平均年龄27岁,平均累计飞行时间830h）。和无飞行经验年龄相仿的对照组人员（丙组）进行复查。结果与5年前MRI结果比较,每组的椎间盘突出数增加,但丙组的骨赘、老飞行员的椎管狭窄数明显增加。与5年前比较,老飞行人员与丙组间的MRI差别降低。结论战斗机飞行员的椎间盘退行性病变的发展可能较早。但是,随着年龄的增加,与对照组的差别逐渐缩小。     

直升机与歼击机飞行员改装体检血尿酸及血脂资料比较分析

目的比较分析直升机与歼击机飞行员改装体检的血尿酸和血脂资料,初步了解上述指标在不同机种飞行员之间的差别。方法收集在我院进行改装体检的82名飞行员的血尿酸及血脂资料,分两组（直升机组和歼击机组各41人）,比较各项指标的组间差别。结果两组年龄及飞行时间均无统计学差别。组间血尿酸及血脂指标（TC、TG、HDL-C）的差别无统计学意义。直升机组血脂异常者共17人（占41.46%）,歼击机组血脂异常者共20人（占48.78%）。直升机组高尿酸血症者3人（占7.32%）,歼击机组高尿酸血症者5人（占12.20%）。组间高尿酸血症及血脂异常发病率的差别无统计学意义。结论参加改装体检的直升机飞行员与歼击机飞行员的血尿酸及血脂指标没有显著差别,但总体高尿酸血症和血脂异常的发生率较高,应注意改装后的健康管理,重点随访。     

MRI cervical spine findings in asymptomatic fighter pilots

MRI of the cervical spine for evaluation concerning degenerative lesions was performed on asymptomatic experienced military high performance aircraft pilots (mean age 42 yr with mean accumulated flying time of 2600 h), and for comparison on age-matched controls without military flying experience. Young military high performance aircraft pilots (mean age 23 yr with 220 h of flying per person) were also examined. There were significantly more osteophytes, disk protrusions, compressions of the spinal cord and foraminal stenoses in the experienced pilots than in the age-matched controls. Low frequency of low grade degenerative lesions was found in the young and inexperienced pilots.     

Phobic fear of flying in aircrews: epidemiological aspects and comorbidity

BACKGROUND: Phobic fear of flying may affect aircrew members during any phase of their flying careers. Symptoms are beyond voluntary control and may lead patients to avoid flying and seek medical advice. METHODS: Of 1101 psychiatric files from our institute for 1985-2002, 150 represented cases of fliers who suffered from phobic fear of flying. Data collected from those files included assessment of fear-evoking situations, type of aircraft, class of aircrew duties, aircraft accident history, past medical history, age, and associated psychiatric comorbidity. RESULTS: We compared a group of 56 pilots with 94 other aircrew members. Results included 143 cases of flight phobia behavior and 7 cases of anxiety about parachuting. Flight phobia was less frequent among pilots (37.4%) than the other aircrew members (62.6%). We found a history of aircraft accident to the patient or an acquaintance in 25% of the cases. Observed comorbid psychiatric disorders (54%) consisted of depressive disorders (22%), anxiety disorders (16%), and personality disorders (7.4%). Fixed-wing pilots and aircrews members had a higher incidence of depression than did rotary-wing pilots and crewmembers (p < 0.05). Rotary-wing pilots and crewmembers had a higher rate of anxiety disorders (p < 0.05). DISCUSSION: Flight phobia encompasses a wide spectrum of clinical origins that may lead pilots or other aircrew members to refuse to fly. We recommend a careful psychiatric evaluation and close follow-up to adequately diagnose fliers with flight phobic reactions, as well as establishing adequate medical and/or psychological treatment.     

G-induced loss of consciousness: case-control study of 78 G-Locs in the F-15, F-16, and A-10

INTRODUCTION: This study determined the trends of reported G-induced loss of consciousness (G-LOC) mishaps from 1980--1999, and determined potential risk factors in pilot characteristics; specifically, 30/60/ 90-h and sortie history, total flight hours, total hours in the aircraft, age, height, weight, and BMI. METHODS: Using aircraft malfunction mishaps to reflect a cross-section of USAF pilots, potential risk factors were determined using a case-control method; cases were all G-LOC mishaps and controls were aircraft malfunction mishaps. The data consisted of 2002 mishap pilots in the history of the F-16, F-15, F-15E, and A-10 from 1980-1999. RESULTS: During this time, G-LOCs represented only 2.5% of all mishaps. The mean engagement number for G-LOC mishaps was three at an average of 8 Gs. A poor anti-G straining maneuver was cited in 72% of the mishaps, fatigue and G-suit malfunction in 19%, low G-tolerance at 14%, and 37% were student pilots. Within pilot characteristics, only two factors were found to be statistically significant: the time in the aircraft and pilot age. In the F-16, there was a 3.5 times greater chance of experiencing a G-LOC mishap if the pilot had less than 600 h in the aircraft [3.5 (1.7-7.2, 95%CI)], and a 9.5 times greater chance in the F-15 [9.5 (2.2-41.9, 95%CI)]. There was a 4.5 times greater chance of experiencing a G-LOC mishap if under the age of 30 in the F-16 [4.5 (2.3-8.5, 95% CI)] and a 3 times greater chance in the F-15 [2.8 (1.2-6.8, 95% CI)]. DISCUSSION: Though it is difficult to predict who will experience G-LOC, emphasis on prevention must be concentrated in training and in pilots new to the aircraft.     

飞行人员耳气压伤的诊治和医学鉴定

目的 通过对40年间住我院飞行人员耳气压伤资料分析,了解耳气压伤的发病情况,并进一步探讨其临床诊治和医学鉴定. 方法 对1967年8月-2007年7月住我院的235例(375耳)耳气压伤飞行人员的资料进行分析:①统计患病年龄、住院年代、飞行机种、飞行职务和飞行时间等与飞行结论 的关系;②按原发性耳气压伤(由咽鼓管周围鼻咽科疾病所致)和继发性耳气压伤(由咽鼓管本身疾病所致)进行分类,并统计其疗效和飞行结论 的关系. 结果 ①耳气压伤在35岁以下占77.0%;在1997年8月-2007年7月仅占14.0%;歼击机飞行员占43.0%,飞行员占70.6%;飞行时间少于1000 h的占51.3%.②继发性耳气压伤治愈率68.9%(164耳/238耳)、停飞率11.2%(18例/160例),原发性耳气压伤治愈率29.2%(40耳/137耳)、停飞率57.3%(43例/75例),差异均有统计学意义(x2=53.8、73.5,P＜0.01). 结论 飞行人员耳气压伤常见,近10年耳气压伤的发生率呈下降趋势,多发生于年轻的歼击机飞行员,且继发性耳气压伤治愈率高于原发性,停飞率低于原发性耳气压伤. Abstract： Objective To summarize the clinical diagnosis, treatment and medical evaluation of barotraumas of ear (BE) by analyzing the inpatients' medical data in past 40 years. Methods The BE cases of 375 ears from 235 aircrews who were hospitalized from August of 1967 to July of 2007,hospitalization, duty, as well as the served aircraft type and flying hours, was respectively analyzed.(induced by the diseases of Eustachian tube itself) were classified and their curative effects were also was younger than 35 yrs. Only 14.0% BE occurred during the period from August of 1997 to July of 2007. In all BE cases, pilots took 70. 6% and the pilots with the flying hours less than 1000 h accounted for 51.3%. 43.0% (101 out of 235) fighter pilots appeared BE and 32.7% of them were permanently grounded, and this percentage was significantly higher than that on other types of aircraft caused 11.2% grounding rate (18 cases out of 160). The primary BE caused 57.3% pilots grounded while its healing rate was 29.2%. The differences were significantly (P＜0. 01). Conclusions BE is common in aircrew, especially in young fighter pilots. It shows a decreased trend in recent 10 year.Secondary BE has higher healing rate than primary BE's and causes lower grounding rate.     

Hypoxia symptoms reported during helicopter operations below 10,000 ft: a retrospective survey

INTRODUCTION: During routine aviation medicine training, rotary-wing aircrew are instructed that the impact of hypoxia on them from flying in unpressurized cabins up to 10,000 ft (3048 m) above mean sea level (AMSL) is relatively small and has few implications for aviation safety. Such reassurance is based on data derived from experiments conducted on resting subjects and may not reflect the true impact of hypoxia in aircrew engaged in operational tasks. METHOD: A survey listing common symptoms of hypoxia was distributed to Australian Army helicopter aircrew who had operated at altitudes up to 10,000 ft AMSL. RESULTS: There were 53 surveys that were returned (71% response), representing 25 loadmasters, 23 pilots, and 5 aircrewman technicians. All respondents were Australian Army aircrew. One or more symptoms consistent with hypoxia were reported by 86.6% of non-pilot aircrew and 60.9% of pilots. 60% of non-pilot aircrew reported four or more symptoms, compared with only 17% of pilots. The most commonly reported symptoms were difficulty with calculations (45%), feeling light-headed (38%), delayed reaction time (38%), and mental confusion (36%). Loadmasters reported more symptoms (mean 5.4) than pilots (mean 2.2) (p < 0.001). From the narratives provided (n = 21), aircrew experienced potentially operationally significant symptoms at a mean altitude of 8462 ft (2579 m). CONCLUSION: The helicopter aircrew surveyed reported symptoms consistent with hypoxia at altitudes within the so-called physiological zone; loadmasters reported more effects than pilots. It may be inappropriate to emphasize the benign nature of the physiological zone during aviation medicine training of a non-resting population such as helicopter aircrew.