Physiologic responses of pilots flying high-performance aircraft

This study deals with the physiologic responses to stress in F-4 fighter pilots and aircrew engaged in surface attack training (SAT) missions. Blood levels of HDL-cholesterol, LDH and LDH isoenzymes, CPK, and myoglobin were determined before and after each mission. Continuous EKG and transcutaneous PO2 recordings were made during briefing, preflight, and inflight. The personal history and habits of each participant were recorded. Each mission consisted of six successive bomb deliveries at 80-s intervals and at increasingly steep dive angles, each terminating in 5.5-6 +Gz during pull-up. Results revealed no apparent effect on HDL, COP isoenzymes, and LDH isoenzymes. Many myoglobin levels dropped as much as 50%. EKG recordings revealed ST elevations, ST depressions, T wave inversions, and marked sinus arrhythmias in some, while others showed increases in cardiac rate. Pilots flying these SAT missions in F-4C aircraft were found not to be significantly physiologically stressed.     

仪表飞行时直升机飞行员脑力负荷的主观评价

目的 脑力工作超负荷可影响人的工作绩效并威胁飞行安全;大部分飞行事故发生在脑力工作负荷强度大的起飞、仪表或手动进近和着陆阶段,而且多是由人为差错引起.因此,为提高飞行作业绩效,维护飞行安全,测量和评定飞行员空中脑力工作负荷具有越来越重要的现实意义.本研究的目的是观察直升机飞行员仪表飞行时的脑力负荷变化.方法 采用修改的美国国家航空航天局任务负荷指数(NASA-TLX)评价量表,对15名直升机飞行员仪表飞行时不同阶段的脑力负荷进行了主观评价;对总脑力负荷评价值和飞行小时数进行了线性回归分析.结果 在起飞爬升阶段、巡航平飞阶段、下滑着陆阶段飞行员的总脑力负荷值分别为34.46±17.25、32.11±13.11和53.95±17.76.下滑着陆阶段飞行员的总脑力负荷值显著高于起飞爬升阶段和巡航平飞阶段的总脑力负荷值(F=25.767,P＜0.01).3个阶段的总脑力负荷的评价值均与飞行小时数呈显著负相关.在起飞爬升阶段,总脑力负荷的评价值与飞行小时数的线性回归方程为:总脑力负荷评价值=42.20-0.012 03×飞行小时数(r=-0.810,P＜0.01);在巡航平飞阶段,线性回归方程为:总脑力负荷评价值=38-51-0.006 04×飞行小时数(r=-0.535,P＜0.05).在下滑着陆阶段,线性回归方程为:总脑力负荷评价值=62.57-0.008 14×飞行小时数(r=-0.532,P＜0.05).结论 军用直升机飞行员仪表飞行时总脑力负荷的评价值与飞行小时数呈显著负相关,在下滑着陆阶段脑力负荷最大.     

Hormonal responses of pilots flying high-performance aircraft during seven repetitive flight missions.

Hormonal responses during seven repetitive flight missions (7RFM) were evaluated on F-4EJ fighter pilots. The following biochemical constituents were measured: 1) cortisol in saliva; 2) 17-OHCS; 3) unbound cortisol; 4) catecholamines in urine; and 5) electrolytes in urine. Samples were collected at about 30 min before the mission, 20 min after each flight, and in a nonflight day for control. The levels of saliva and urine corticosteroids slightly increased during 7RFM when compared with controls. The concentrations of urine catecholamines during 7RFM were significantly higher than those of preflight and control. These data suggest that flight stresses were moderate for the pilots flying 7RFM.     

Stress and workload in pilots

Several studies have highlighted the increase in physiological activity which occurs in pilots during flight and especially during takeoffs and landings. For example, it has been clearly demonstrated that pilots' heart rates increase during the landing approach to reach a peak at or just before touchdown. These changes have been attributed to workload and to psychological or emotional stress. This paper examines a number of test pilots' heart rate responses recorded during various flight trials involving different types of aircraft. Examples include ramp takeoffs in a VTOL fighter, automatic landings in fog, supersonic flight through monsoon rain, and a sortie in which the pilot developed acute appendicitis. It is concluded that heart rate responses in experienced pilots are influenced almost entirely by workload-related factors and not by emotional stressors, such as risk and anxiety. Because of the emotional overtones of the word "stress," it is suggested that the term workload should be used when referring to the reason for increased cardiovascular activity of pilots.     

Vestibular habituation in student pilots

The dynamics of vestibular nystagmus were measured in 42 military student pilots (age 19 to 21). Their responses were compared with 40 non-flying subjects of similar age who were also fulfilling requirements for the mandatory Swiss military service. The following differences emerged: the time constant of the nystagmus response after vestibular stimulation was shorter (p less than 0.001; t-test) in student pilots, whereas the gain tended to be higher (p less than 0.025). These changes in the response dynamics are attributed to habituation. Student pilots were additionally tested with conflicting visual-vestibular stimulation. Nystagmus response was delayed and attenuated when compared to stimulation in darkness. Under these conditions motion sickness occurred in one third of the subjects. We found no relation between the occurrence of motion sickness and the value of the time constant or gain of vestibular nystagmus. Results show that there is no single "normal" value of vestibular nystagmus. This becomes important when defining "normal" values as opposed to pathological values in vestibular testing.     

Short-term vestibular responses to repeated rotations in pilots

INTRODUCTON: It has been suggested that vestibular function in pilots differs from that of non-pilots. METHODS: Short-term vestibular responses to repeated rotations were explored in pilots and non-pilots using a rotating chair. Vestibulo-ocular reflex tests were done in 30 pilots (VOR-P) and 30 non-pilots (VOR-NP) at rotation frequencies of 0.01, 0.02,0.04, 0.08, 0.16, and 0.32 Hz. In a separate experiment, VOR tests were done at 0.16 Hz before and after four successive velocity-step tests in twenty-five pilots (STEP-P) and their results were compared with the results of twenty-five non-pilots (STEP-NP) who were studied earlier. RESULTS: VOR-P exhibited normal VOR gains (mean values 0.47, 0.57, 0.63, 0.69, 0.67, and 0.74, respectively, for the frequencies listed above) compared with those of VOR-NP (0.48, 0.54, 0.59, 0.67, 0.72, and 0.79). VOR gain at 0.16 Hz showed little change in STEP-P (0.64 +/- 0.04 to 0.58 +/- 0.032), while it increased in STEP-NP (0.59 +/- 0.03 to 0.78 +/- 0.06). DISCUSSION: VOR gain may be a useful measurement for differentiating pilots' vestibular function from that of non-pilots. After-rotary VOR may be suppressed in pilots.     

飞行学员Coriolis加速度刺激时的胃电图观察

目的观察和比较飞行学员与地勤人员在Ｃｏｒｉｏｌｉｓ加速度刺激时的前庭植物神经反应。方法在平静状态和Ｃｏｒｉｏｌｉｓ加速度刺激时，描记３２名飞行学院经过检验飞行后的飞行学员和３２名地勤人员的胃电图（ＥＧＧ），同时记录诱发性运动病的症状。结果飞行学员和地勤人员相比，平静状态的ＥＧＧ频率和振幅及加速度刺激时ＥＧＧ频率均无明显差异。但Ｃｏｒｉｏｌｉｓ加速度刺激时飞行学员的ＥＧＧ振幅及诱发性运动病症状的发生率明显低于地勤人员。结论经过选飞和检验飞行训练的飞行学员其前庭植物神经反应的稳定性高于地勤人员。     

Use of flying tests for evaluating functional capabilities of pilots

Psychophysiological parameters of 89 pilots were examined when they performed flight tasks on a trainer under normal and complicated conditions. The experiments helped to reveal a group of test subjects (11.2%) who had low capabilities and made serious errors. The results obtained suggest that psychophysiological examinations during simulated professional activity can be recommended as a method to be used for measuring adaptive and compensatory capabilities of pilots undergoing medical expertise.     

歼击机飞行员飞行不合格的疾病谱分析

目的分析歼击机飞行员飞行不合格疾病谱,为新时期航卫保障提供参考依据.方法对空军总医院收集的飞行不合格的300名歼击机飞行员病例资料按疾病类别、涉及专科及不同年龄段进行分类计数.结果①歼击机飞行员飞行不合格的常见疾病为空中晕厥、加速度耐力不良、地面晕厥、航空性中耳炎、飞行错觉、眩晕、颈椎病、屈光不正、神经衰弱和血管性头痛等.②与歼击机飞行员飞行不合格最相关的专科有神经科、耳鼻咽喉科和骨科等.③飞行不合格的飞行员多集中在25～34岁间.结论与航空环境相关的一些疾病是空军总医院收集的歼击机飞行员飞行不合格的重要原因,今后应有针对性地加强歼击机飞行员的日常训练,同时重视社会-心理因素对飞行员的影响.     

飞行员肾脏小结石带石飞行初步观察

目的 观察飞行因素对肾脏小结石移位的影响,探讨飞行员肾脏小结石特许飞行标准. 方法 回顾性分析2005年9月-2012年6月因肾结石入住空军总医院、经治疗后特许带石飞行的空军17例飞行员临床及随访资料. 结果 患者均为男性,年龄23～46岁,平均34.4岁.左肾结石7例,右肾结石4例,双肾结石6例.单座机飞行员9人,双座机飞行员8人.平均特许飞行时间110 h(30～240 h).所有患者均为经体外冲击波碎石术+药物排石或微创手术综合治疗后仍有残留结石;残石大小2～4 mm,经运动试验后复查CT结石无移位,尿常规红、白细胞数量正常,准予特许飞行.单座机飞行员每3个月复查,双座机飞行员每6个月复查,观察项目包括症状、泌尿系统CT扫描以及尿常规检查.所有患者随访期间均无飞行过程中肾绞痛发作.3例双座机飞行员在地面排石时出现腰部不适,但无绞痛发作,复查CT结石消失;其余14例患者均无症状,定期泌尿系统CT检查提示结石大小、位置无变化,尿常规正常. 结论 肾脏小结石＜4 mm,排石时一般无绞痛发作,飞行因素不影响小结石移位;对结石＜3 mm的飞行员,在严密观察下特许飞行是可行的.     

Pneumomediastinum in student aviators: 10 cases with return to flying duty

Pneumomediastinum (PnM) is an uncommon phenomenon, though it is one of the most common causes of chest pain in young adults. It may be particularly important among aviators, as it may result in in-flight incapacitation. Spontaneous PnM is a variant usually associated with the Valsalva maneuver, used during high-performance flight. This may increase the risk of PnM recurrence and raises concern regarding the return to flight duties of aviators after an episode of spontaneous PnM. We present 10 student aviators who experienced a single episode of uncomplicated PnM unassociated with flight. All were returned to flying duty following a normal pulmonary evaluation and are still in active duty. Follow-up was conducted for a mean period of 74.7 mo without any adverse consequences. These findings support the return of aviators to flying duty after a single episode of uncomplicated spontaneous PnM.     

Trapezius muscle metabolism measured with NIRS in helicopter pilots flying a simulator

INTRODUCTION: This study examined metabolic and hemodynamic responses during night vision goggle (NVG) induced neck strain among military helicopter pilots. We hypothesized that near infrared spectroscopy (NIRS) would be capable of identifying metabolic differences in the trapezius muscles of pilots between simulated flights with and without NVG. METHODS: There were 33 pilots who were monitored on consecutive days during Day and NVG flight simulator missions. NIRS probes were attached bilaterally to the trapezius muscles at the C7 level to record total oxygenation index (TOI, %), total hemoglobin (tHb), oxyhemoglobin (HbO2), and deoxyhemoglobin (HHb). RESULTS: Significant differences in tHb were found between Day (0.51+/-2.31 micromol x cm (-1)) and NVG (4.14 +/- 2.74 micromol x cm(-1)) missions, and for HbO2 (Dayend 2.63+/-1.64 micromol x cm(-1); NVGend 5.77+/-1.98 micromol x cm(-1)). Significant left and right side differences between Day and NVG were found for tHb (NVGleit -1.83+/-2.55; NVGright 10.45+/-2.86 micromol x cm(-1)), HbO2 (NVGleft 1.77+/-1.90; NVGright 9.95+/-2.07 micromol x cm(-1)), and HHb (Dayleft -1.84+/-0.95; Dayright -2.32+/-0.87 micromol x cm (-1); NVGleft -3.60+/-1.05 micromol x cm(-1); NVGright 0.49+/-1.16 micromol x cm(-1). DISCUSSION: These results support NIRS's utility in assessing the significant metabolic and hemodynamic effects of NVG on neck musculature during real-time missions for 1) left and right side differences; and 2) Day vs. NVG missions. The additional mass of the NVG equipment does increase the metabolic stress of these muscles during simulated missions.