The effect of aircraft control forces on pilot performance during instrument landings in a flight simulator

BACKGROUND: Pilots may have difficulty controlling aircraft at both high and low force levels due to larger variability in force production at these force levels. The aim of this study was to measure the force variability and landing performance of pilots during an instrument landing in a flight simulator. METHODS: There were 12 pilots who were tested while performing 5 instrument landings in a flight simulator, each of which required different control force inputs. Pilots can produce the least force when pushing the control column to the right, therefore the force levels for the landings were set relative to each pilot's maximum aileron-right force. The force levels for the landings were 90%, 60%, and 30% of maximal aileron-right force, normal force, and 25% of normal force. Variables recorded included electromyographic activity (EMG), aircraft control forces, aircraft attitude, perceived exertion and deviation from glide slope and heading. Multivariate analysis of variance was used to test for differences between landings. RESULTS: Pilots were least accurate in landing performance during the landing at 90% of maximal force (p < 0.05). There was also a trend toward decreased landing performance during the landing at 25% of normal force. Pilots were more variable in force production during the landings at 60% and 90% of maximal force (p < 0.05). CONCLUSION: Pilots are less accurate at performing instrument landings when control forces are high due to the increased variability of force production. The increase in variability at high force levels is most likely associated with motor unit recruitment, rather than rate coding. Aircraft designers need to consider the reduction in pilot performance at high force levels, as well as pilot strength limits when specifying new standards.     

Measuring the effects of neurotoxicants on flight simulator performance

The Aviation Research Laboratory has developed a methodology for evaluating toxicant effects on pilot performance. Flight data are collected using a digital flight simulator, the ILLIMAC (ILLInois Micro Aviation Computer), during holding patterns and instrument landing system approaches. The flight data are recorded by a separate microcomputer, which also presents the Sternberg memory searching task. A preliminary study examined pilot performance in the simulator and cholinesterase inhibition by insecticides in agricultural pilots. The correlation between the physiological parameters and the pilot performance data was determined. Experiments are planned to determine the effects of a variety of drugs on pilot performance. Neurotoxicants to be studied include ethanol, three antiemetic drugs, and atropine sulfate.     

Heart rate and performance during combat missions in a flight simulator

INTRODUCTION: The psychological workload of flying has been shown to increase heart rate (HR) during flight simulator operation. The association between HR changes and flight performance remains unclear. METHODS: There were 15 pilots who performed a combat flight mission in a Weapons Tactics Trainer simulator of an F-18 Hornet. An electrocardiogram (ECG) was recorded, and individual incremental heart rates (deltaHR) from the HR during rest were calculated for each flight phase and used in statistical analyses. The combat flight period was divided into 13 phases, which were evaluated on a scale of 1 to 5 by the flight instructor. RESULTS: HR increased during interceptions (from a mean resting level of 79.0 to mean value of 96.7 bpm in one of the interception flight phases) and decreased during the return to base and slightly increased during the ILS approach and landing. DeltaHR appeared to be similar among experienced and less experienced pilots. DeltaHR responses during the flight phases did not correlate with simulator flight performance scores. Overall simulator flight performance correlated statistically significantly (r = 0.50) with the F-18 Hornet flight experience. CONCLUSIONS: HR reflected the amount of cognitive load during the simulated flight. Hence, HR analysis can be used in the evaluation of the psychological workload of military simulator flight phases. However, more detailed flight performance evaluation methods are needed for this kind of complex flight simulation to replace the traditional but rough interval scales. Use of a visual analog scale by the flight instructors is suggested for simulator flight performance evaluation.     

Effect of caffeine on simulator flight performance in sleep-deprived military pilot students

Caffeine has been suggested to act as a countermeasure against fatigue in military operations. In this randomized, double-blind, placebo-controlled study, the effect of caffeine on simulator flight performance was examined in 13 military pilots during 37 hours of sleep deprivation. Each subject performed a flight mission in simulator four times. The subjects received either a placebo (six subjects) or 200 mg of caffeine (seven subjects) 1 hour before the simulated flights. A moderate 200 mg intake of caffeine was associated with higher axillary temperatures, but it did not affect subjectively assessed sleepiness. Flight performance was similar in both groups during the four rounds flown under sleep deprivation. However, subjective evaluation of overall flight performance in the caffeine group tended to be too optimistic, indicating a potential flight safety problem. Based on our results, we do not recommend using caffeine pills in military flight operations.     

Relationship of CogScreen-AE to flight simulator performance and pilot age

OBJECTIVES: We report on the relationship between CogScreen-Aeromedical Edition (AE) factor scores and flight simulator performance in aircraft pilots aged 50-69. METHODS: Some 100 licensed, civilian aviators (average age 58+/-5.3 yr) performed aviation tasks in a Frasca model 141 flight simulator and the CogScreen-AE battery. The aviation performance indices were: a) staying on course; b) dialing in communication frequencies; c) avoiding conflicting traffic; d) monitoring cockpit instruments; e) executing the approach; and f) a summary score, which was the mean of these scores. The CogScreen predictors were based on a factor structure reported by Kay (11), which comprised 28 CogScreen scores. Through principal components analysis of Kay's nine factors, we reduced the number of predictors to five composite CogScreen scores: Speed/Working Memory (WM), Visual Associative Memory, Motor Coordination, Tracking, and Attribute Identification. RESULTS: Speed/WM scores had the highest correlation with the flight summary score, Spearman r(rho) = 0.57. A stepwise-forward multiple regression analysis indicated that four CogScreen variables could explain 45% of the variance in flight summary scores. Significant predictors, in order of entry, were: Speed/WM, Visual Associative Memory, Motor Coordination, and Tracking (p<0.05). Pilot age was found to significantly improve prediction beyond that which could be predicted by the four cognitive variables. In addition, there was some evidence for specific ability relationships between certain flight component scores and CogScreen scores, such as approach performance and tracking errors. CONCLUSIONS: These data support the validity of CogScreen-AE as a cognitive battery that taps skills relevant to piloting.     

The effect of repeated doses of 30 mg pyridostigmine bromide on pilot performance in an A-4 flight simulator

The effect of repeated doses of 30 mg pyridostigmine bromide every 8 h on flight skills in an A-4 simulator was tested in this crossover double-blind placebo-controlled study on 10 pilots experienced in actual and simulated A-4 flights. The pilots flew two test simulator flights 2 h after the fourth dose of pyridostigmine or placebo. The flight profile included navigation, rapid ascent, 360 degrees turns, and instrument landing. Each flight lasted approximately 20 min. Flight parameters measured included indicated air speed, true heading, barometric altitude, vertical velocity, and bank. The mean whole blood cholinesterase inhibition level was 29%. There was no decrement in performance under treatment with pyridostigmine in the percent of deviation time from the prescribed limits or in the average duration or magnitude of the deviation in each of the flight parameters. We conclude that pyridostigmine bromide in repeated doses of 30 mg every 8 h does not appear to influence pilot performance during short A-4 missions.     

模拟飞行条件下双重任务时飞行员心理生理参数的变化特点

测量了50名健康飞行员和13名康复疗养飞行员，在模拟飞行条件下双重任务时的心理生理反应。结果发现，模拟飞行各阶段心率变化趋势与实际飞行基本一致，但变化幅度较低。双重任务时，反映情绪性变化的心率、呼吸率及肺通气量明显增加，与思维活动有关的眨眼率增加。心理运动反应速度与飞行操纵质量相互影响，其程度有个体差异。同时在该负荷环境下，发现5例心律失常的无症状飞行员。结果提示，模拟飞行双重任务条件可以造成飞行员心理生理负荷，并可能有助于发现一些潜在性病症。     

仪表飞行条件下飞行错觉与仪表注视的相关分析

目的 分析仪表飞行条件下飞行错觉发生情况与仪表注视的相互关系。方法 对45名飞行员进行仪表飞行试验,记录其飞行错觉情况、仪表扫视情况及眼动情况,并对以上指标进行偏相关分析。结果 飞行员仪表飞行错觉水平与飞行错觉后反应（r=0.620,P=0.000）、升降速表注视时间（r=0.372,P=0.014）呈显著正相关;与高度表反应正确率（r=-0.304,P=0.047）、地平仪反应正确率（r=-0.311,P=0.042）呈现显著负相关。结论 飞行员仪表飞行错觉的发生与高度表、地平仪及升降速表的正确判读具有一定关联,视觉搜索效率较低可能是飞行错觉发生的重要原因或重要中介因素。     

高性能战斗机飞行员仪表视觉空间定向能力训练效果观察

Objective To explore effectiveness of improving the abilities of instrument visual spatial orientation (IVSO) training for high performance fighter pilots. Methods An IVSO training device was developed.Based on the principles of computer graphics and characteristics of cognition,4 kinds of instrument flight condition patterns were adopted as training profiles.Eleven pilots were trained along these four training profiles for five times,include recognizing and flying by instrument and head-up display respectively in complicated flight sortie or with interference.The reaction time,rate of correct operation,deviation angle of attitude and the adjunctive task completion rate were recorded and compared. Results In pre-and post-IVSO training,the reaction times got with instrument and head-up display in complicated flight sortie were (1.42±0.24)s vs.(0.99±0.13)s and(1.54±0.29)s vs.(1.05±0.12)s respectively while the rates of correct operations were 53.91%±9.12%vs.90.00%±5.88%and 73.09%±12.02%vs.89.18%±6.10% respectively.Deviation angles of roll and pitch in maintaining flight attitude by instrument training were 3.25°±0.60°vs.2.07°±0.25°and 2.41°±0.63°vs.1.87°±0.30°respectively,comparing to 3.08°±1.03°vs.2.06°±0.35°and 2.84°±0.67°vs.1.99°±0.20°in attitude maintenance by head-up display.Adjunctive task correct rates with believing instrument and head-up display were 63.90%±11.15%vs.88.27%±10.23%and 59.73%±12.81%vs.82.09%±9.62% respectively.All differences between pre-and post-IVSO trainings are statistically significant (t=2.47 to 11.03,P<0.01 or P<0.05). Conclusions The adopted instrument flight training can remarkably improve pilot's IVSO abilities.     

高性能战斗机飞行员仪表视觉空间定向能力训练效果观察

目的 探讨训练和提高飞行员仪表视觉空间定向能力的方法,并观察训练效果. 方法 对某部11名高性能战斗机飞行员分别进行仪表复杂状态的判断和操纵、平视仪复杂动作的判断和操纵、坚信仪表及坚信平视仪4个项目各5次的训练,在训练前后分别记录其判断反应时、操作正确率、飞机姿态偏差角和附加任务正确率等参数并进行比较. 结果 训练前后,仪表复杂状态判断的操纵判断反应时和操纵正确率分别为(1.42±0.24)s和(0.99±0.13)s、(53.91±9.12)%和(90.00±5.88)%;平视仪复杂状态判断的操纵判断反应时和操纵正确率分别为(1.54±0.29)s、(1.05±0.12)s、(73.09±12.02)%和(89.18±6.10)%;坚信仪表飞行姿态坡度偏差和俯仰角偏差分别为3.25°±0.60°和2.07°±0.25°、2.41°±0.63°和1.87°±0.30°;坚信平视仪飞行姿态坡度偏差和俯仰角偏差分别为3.08°±1.03°和2.06°±0.35°、2.84°±0.67°和1.99°±0.20°;坚信仪表和坚信平视仪飞行附加任务正确率分别为(63.90±11.15)%和(88.27±10.23)%、(59.73±12.81)%和(82.09±9.62)%.训练前后各参数比较差异均有统计学意义(t=2.47～11.03,P<0.01或P<0.05). 结论 通过飞行员仪表视觉空间定向能力训练可明显提高飞行员的仪表视觉空间定向能力水平. Abstract： Objective To explore effectiveness of improving the abilities of instrument visual spatial orientation (IVSO) training for high performance fighter pilots. Methods An IVSO training device was developed.Based on the principles of computer graphics and characteristics of cognition,4 kinds of instrument flight condition patterns were adopted as training profiles.Eleven pilots were trained along these four training profiles for five times,include recognizing and flying by instrument and head-up display respectively in complicated flight sortie or with interference.The reaction time,rate of correct operation,deviation angle of attitude and the adjunctive task completion rate were recorded and compared. Results In pre-and post-IVSO training,the reaction times got with instrument and head-up display in complicated flight sortie were (1.42±0.24)s vs.(0.99±0.13)s and(1.54±0.29)s vs.(1.05±0.12)s respectively while the rates of correct operations were 53.91%±9.12%vs.90.00%±5.88%and 73.09%±12.02%vs.89.18%±6.10% respectively.Deviation angles of roll and pitch in maintaining flight attitude by instrument training were 3.25°±0.60°vs.2.07°±0.25°and 2.41°±0.63°vs.1.87°±0.30°respectively,comparing to 3.08°±1.03°vs.2.06°±0.35°and 2.84°±0.67°vs.1.99°±0.20°in attitude maintenance by head-up display.Adjunctive task correct rates with believing instrument and head-up display were 63.90%±11.15%vs.88.27%±10.23%and 59.73%±12.81%vs.82.09%±9.62% respectively.All differences between pre-and post-IVSO trainings are statistically significant (t=2.47 to 11.03,P<0.01 or P<0.05). Conclusions The adopted instrument flight training can remarkably improve pilot's IVSO abilities.     

飞行模拟机医学检查在外科体检鉴定中的应用

肌力应当满足行使执照权利的需要. 结果 5例中上肢肌力异常的1例,下肢肌力异常的2例,下肢髋关节活动度下降的2例,接受飞行模拟机医学检查均合格,最终外科结论合格.随访时间4个月～8年,飞行良好,未出现因飞行操作能力下降所致的飞行事故或飞行事故征候. 结论 对于某些骨骼肌肉系统异常可以通过飞行模拟机医学检查进行评价,如果疾病为良性进程,接受D级全动飞行模拟机医学检查提示能够满足飞行需要可考虑评定为合格,并密切随访.     

The effects of single-dose fexofenadine,diphenhydramine, and placebo on cognitive performance in flight personnel

BACKGROUND: Sedation and functional impairments are side effects associated with the use of first-generation antihistamines that preclude their use in aviation. Selected second-generation antihistamines do not have such side effects and have been proposed for use in aircrew. METHODS: Forty-two healthy naval aviation personnel served as subjects in this double-blind, randomized, placebo-controlled crossover study. Subjective drowsiness, cognitive performance, and vigilance were measured under three conditions: 180 mg fexofenadine (F), 50 mg diphenhydramine (D) as a positive control, or placebo (P). RESULTS: Subjects receiving F vs. D tended to have a faster mean hit reaction time (adjusted mean difference +/- SE, -10.5 +/- 6.8 ms, p = 0.127). Subjects performed faster and better with F vs. D on measures of omission errors and commission errors (p < 0.05). Variable symbol digit coding delayed recall accuracy was better for F vs. D (p = 0.023), and approached significance for shifting attention and divided attention tasks (p = 0.062 and p = 0.057, respectively). Subjects reported significantly more drowsiness (p < 0.005) with D than F. CONCLUSIONS: Diphenhydramine administration resulted in significant psychomotor decrements compared with fexofenadine, while the effects of fexofenadine were similar to placebo. These results provide additional support for the safe use of fexofenadine by aviation personnel.     

Modafinil's effects on simulator performance and mood in pilots during 37 h without sleep

INTRODUCTION: Modafinil is a relatively new alertness-enhancing compound of interest to the military aviation community. Although modafinil has been well-tested in clinical settings, additional studies are required to establish its safety and efficacy for use in pilots. OBJECTIVE: The purpose of this study was to determine whether modafinil (100 mg after 17, 22, and 27 h without sleep) would attenuate the effects of fatigue on fighter-pilot mood and performance during 37 h of continuous wakefulness. METHODS: A quasi-experimental, single-blind, counterbalanced design tested the effects of modafinil in 10 Air Force F-117 pilots. RESULTS: Modafinil attenuated flight performance decrements on six of eight simulator maneuvers. Overall, modafinil maintained flight accuracy within approximately 15-30% of baseline levels, whereas performance under the no-treatment/placebo condition declined by as much as 60-100%. Modafinil decreased self-ratings of depression and anger, while improving ratings of vigor, alertness, and confidence. Benefits were most noticeable after 24 to 32 h of continuous wakefulness. One potential drawback of modafinil was that, at least at the 100-mg dose level, the drug's effects were not subjectively salient. Since this may lead personnel to escalate the dose without flight surgeon approval, personnel should be cautioned regarding this particular drug characteristic. CONCLUSION: Although modafinil did not sustain performance at predeprivation levels, the present study suggests that modafinil should be considered for the military's armament of short-term fatigue countermeasures. Future research will evaluate whether 200-mg doses are more beneficial than the 100-mg doses used here.     

飞行定向的空间认知特征研究

目的 寻求飞行定向认知特征的检测方法，预测飞行员的空间认知水平。方法 采用认知分化测验(CLB)、团体镶嵌图形测验(GEFT)以及飞行定向水平的模糊评价技术，对85名飞行员的认知特征、场独立性和飞行空间定向水平进行了评价。结果 ①高水平的视觉空间认知能力及较强的场独立性特征不仅有助于获得一个良好的飞行定向水平，而且还构成了预测定向水平差异的有效指标；②轻度错觉的飞行员与中、重度错觉水平组飞行员在空间认知、认知分化和场独立性上的得分分别构成了显著的差异，表明轻度组飞行员在空间定向中表现出了良好的视觉空间信息组织、加工和某些元认知技能方面的优势。结论 本研究方法可应用于预测飞行员的空间认知水平。     

Evaluation of pharmacological aids on physical performance after a transmeridian flight

PURPOSE: The purpose of this study was to evaluate physical performance (static and dynamic) of U.S. Air Force reservists after an eastbound air travel across seven time zones and to estimate the pharmacological aids slow-release caffeine and melatonin versus placebo in attempt to overcome the decline in performance. METHODS: 27 American volunteers were randomly divided into three groups: caffeine 300 mg, melatonin 5 mg, and placebo (lactose capsules). Two days before the flight and 10 d after, three tests were performed: hand grip strength test (static performance), squat jump test (maximal height), and multiple jump test (power and endurance). All measures were repeated twice a day: morning and afternoon. RESULTS: In placebo conditions, the static performance of the dominant hand decreased significantly during the first three mornings and tended to decrease the fourth morning. Simultaneously, the caffeine group's static performance increased significantly, whereas the melatonin group maintained its levels. No significant differences were observed the afternoons. No statistical differences appeared for the nondominant hand in the mornings or afternoons. Dynamic capacities presented no significant degradation after the travel. In the placebo group, for the squat jump test, performance increased from the fourth day. No real explanation can be given about this result. CONCLUSIONS: We demonstrated that slow-release caffeine and melatonin might be used to compensate for jet-lag troubles and particularly for the static physical performance decrease. The slow-release caffeine seems to be the best treatment, but its effects are only demonstrated on previously damaged performance. These preliminary results need further investigation, but we are the first to report a beneficial effect of slow-release caffeine and melatonin on physical performances after jet-lag.