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Exposure to altered g-levels causes unusual sensorimotor demands that must be dealt with by the brain. This study aimed to investigate whether fighter pilots, who are exposed to frequent g-level transitions and high g-levels, show differential functional characteristics compared to matched controls, indicative of neuroplasticity. We acquired resting-state functional magnetic resonance imaging data to assess brain functional connectivity (FC) changes with increasing flight experience in pilots and to assess differences in FC between pilots and controls. We performed whole-brain exploratory and region-of-interest (ROI) analyses, with the right parietal operculum 2 (OP2) and the right angular gyrus (AG) as ROIs. Our results show positive correlations with flight experience in the left inferior and right middle frontal gyri, and in the right temporal pole. Negative correlations were observed in primary sensorimotor regions. We found decreased whole-brain functional connectivity of the left inferior frontal gyrus in fighter pilots compared to controls and this cluster showed decreased functional connectivity with the medial superior frontal gyrus. Functional connectivity increased between the right parietal operculum 2 and the left visual cortex, and between the right and left angular gyrus in pilots compared to controls. These findings suggest altered motor, vestibular, and multisensory processing in the brains of fighter pilots, possibly reflecting coping strategies to altered sensorimotor demands during flight. Altered functional connectivity in frontal areas may reflect adaptive cognitive strategies to cope with challenging conditions during flight. These findings provide novel insights into brain functional characteristics of fighter pilots, which may be of interest to humans traveling to space.

BACKGROUND: in-flight physiologic episodes (PHYSEPs) among high-performance aircraft pilots have been attributed hypoxia or g-induced loss of consciousness (GLOC). Accordingly, training, pilot selection, and incident response investigations have been centered around this paradigm. However, as jet life support systems and aircrew flight equipment have improved, it stands to reason that these traditionally-attributed causes of PHYSEPs may be incomplete. In the last decade, multiple PHYSEPs have been noted among 4th- and 5th-generation fighter pilots in multiple services that do not appear to be connected to hypoxia or GLOC. DESCRIPTION: In order to facilitate international information sharing and create a consensus understanding of PHYSEPs, a North American Treaty Organization (NATO) working group was formed in 2018. This group has 20+ members representing 10 NATO and partner nations. The group expects to finalize its report in 2024, which will include findings and recommendations, PHYSEP classification and definition, a matrix of exposures present in the high-performance aviation environment, supporting factors such as training, sensors, and organization, and a construct for a multi-national study. DISCUSSION: PHYSEP symptom presentation can vary widely, and the cause of PHYSEPs are multifactorial and variable; PHYSEPs are often a normal physiologic response to abnormal physiologic environments. An understanding of the multiple exposures that may lead to symptoms and of the potential outcomes of those exposures, is critical to understanding PHYSEPs. Not all relevant exposures and outcomes are well-understood, and the multifactorial nature of PHYSEPs requires an understanding of the interactions between exposures and physiologic responses; this requires specialized knowledge and a comprehensive and systematic assessment by a specialist. A current understanding of the rapidly evolving state of PHYSEP science is critical to assessment of PHYSEPs. A future aircrew experience study comparing PHYSEPs across multiple nations and airframes will be discussed. Learning Objectives 1. Understand the findings and recommendations of the NATO working group. 2. Describe the differing presentations and potential causes of physiological episodes. [ABSTRACT FROM AUTHOR]

INTRODUCTION: This case report describes a G-LOC due to a push-pull-effect (PPE) on a Eurofighter pilot performing intercept maneuvers. The thermal burden and dehydration were aggravating factors. BACKGROUND: The push-pull-effect (-Gz to +Gz transition) is of great operational relevance. Blood pressure and heart rate respond to sudden changes of gravity. A reduced +Gz-tolerance is the result. Push-pullmaneuvers were associated with approximately 30% of the G-LOC events. CASE PRESENTATION: Due to a high administrative workload, the pilot (31-year-old male) had no time for lunch and sufficient hydration. The outside temperature was 86° F and the air conditioning of the building was insufficient. On his second flight of the day, the pilot was practicing intercept maneuvers with his wingman. In preparation for the next intercept, he intended to turn the switch for the harness lock into the lock position but inadvertently he turned off the G-protection system. He turned into an inverted flight for 9 seconds with a maximum of -1.5 Gz. The altitude decreased to 21,600 ft. His wingman was flying at 16,000 ft and the pilot started the intercept maneuvers with a g load of 6.1 Gz. At 17,400 ft, the positive G exposure stopped and the aircraft descended unexpectedly in a nearly vertical flight. In accordance with the investigation report, the stick had been in the center position for 11 seconds without any input. One second after the voice warning "pull up", the pilot tried to recover the situation with maximum stick input (9,1 Gz). The minimum altitude at this maneuver was 3,520 ft. The pilot was able to stabilize the aircraft and declared an in-flight emergency as a "physiological incidence" and returned safely to the air base. The amnesia in combination with the lack of stick activity suggests that the pilot fell into G-LOC. DISCUSSION: Military pilots are aware of the risk of +Gz exposure. The risk of the PPE significantly to reducing the pilot's Gz-tolerance is not well known among high-performance aircrew. As a matter of principle, aeromedical training shall include educating pilots about the harmful effects of push-pull-maneuvers. Contributing factors like thermal heat stress and dehydration have a negative impact on Gz tolerance and should be addressed to flight personnel. Aircrew should be reminded not to rely entirely on the G-protection system as it sometimes does not work, like in this case where the G valve was inadvertently turned off. Learning Objectives 1. The audience will learn about the harmful effects og push pull maneuvers. 2. The audience will learn about the importance of aeromedical training. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Up to 97% of fighter pilots report neck pain from high +Gz forces, but the etiology has not been clearly defined (PMID: 21614872). This study will explore the etiology of chronic neck pain and acute activity-related flare-ups using pain and functional assessments, structural and advanced MRI scans, and inflammatory and stress biomarkers using annual baseline assessments and intermittent assessments linked to flight exposures. Correlations of baseline pain and functional data with flight history are presented here. METHODS: Wisconsin Air National Guard (WIANG) fighter pilots participated in demographic and flight history surveys, anthropometric measurements, and pain and functional assessments. Pain assessments included eight validated questionnaires focused on the intensity, characteristics, and interference of neck and back pain. Functional assessments included cervical range of motion (CROM) and neck strength movements to assess neck functionality. RESULTS: Twelve males and one female participated with a mean age of 39 (range: 28-46) years, 2268 (500-3500) total military flight hours and a Neck Disability Index (NDI) of 7 (1-18). Most flight hours (69.0%) were flown in the F-16, with 5.8% in the F-35 that WIANG pilots began flying in Spring 2023. NDI was negatively correlated with all six bending CROM movements (r>0.62, p<0.04) and positively correlated with F-16 flight hours (r=0.43, p=0.14). The number of flight hours in the past year was negatively correlated with all eight neck strength assessments except flexion (r>0.7, p<0.007). DISCUSSION: These baseline results highlight the complex relationships between total and recent military flight time, neck and back pain, and functional disability. Pilots with increased flight time tended to have reduced neck strength and CROM, along with increased pain scores. These functional deficits may interfere with a pilot's effectiveness during flight. Pilots report avoiding neck rotation movements like aerial combat maneuvers and checking six due to anticipation of pain (PMID: 18717118). This study will focus on multiple flight exposures per year to understand the etiology of this pain and differentiate between pain profiles linked to chronic versus acute flight exposures. This information can guide further research in finding methods to reduce the burden of neck and back pain in military aircrew. Learning Objectives 1. The audience will understand the type of pain experienced by fighter pilots due to their exposure to +Gz forces using results from pain assessments. 2. The audience will understand the functional effects experienced by fighter pilots due to this pain and repeated exposure to +Gz forces. [ABSTRACT FROM AUTHOR]

INTRODUCTION: This is a case of a fatal F-16 mishap due to G-induced loss of consciousness (GLOC), that highlights physiologic factors which may decrease a pilot's tolerance of G forces. BACKGROUND: G forces continue to be a significant threat in fighter aviation. Safety data shows that 157 G-related mishaps occurred between FY01 and FY11 with five Class As and three fatalities costing $86.2M. Almost all military pilots, as part of their flight training, will undergo some exposure to the high +G environment. Fast jet operations, however, are where the vast majority of high +G exposure occurs. Fighter pilots are given extensive tools and training to overcome the effects of +G, including centrifuge training, advanced technology anti-G suits (ATAGS), positive pressure breathing for +G, physical conditioning, and refresher training on the anti-G straining maneuver (AGSM) continuously throughout their careers. CASE PRESENTATION: The mishap pilot was a physically fit 34-yr-old man. He had over 600 total flying hours. He was a pilot instructor on T-6A and completed training the T-38 prior to entering training in the F-16. On a regular training sortie, the pilot executed a maneuver that caused him to experience negative G followed immediately by + 9G at which point he experienced GLOC. The pilot regained some level of consciousness prior to crashing and tried to eject, however, it was unsuccessful. The aircraft was destroyed and the pilot dead. He was current on all Aerospace Physiology training. Prior to the mishap sortie. After the crash, a postmortem tissue examination detected the consumption of a nutritional supplements. No carbon monoxide, ethanol, or illegal substances. The mishap aircraft was an F-16CM built in1991. DISCUSSION: This tragic accident is one of many that have occurred in military fighter pilots. As flight surgeons, we should be award of all factors that may negatively contribute to a pilots abilities in the jet, and be ready to educate air crew about how to stay healthy. In this presentation we will discuss some specific factors that affect G tolerance, including the push-pull effect, the effect of lifestyle on physiologic compensation and decision making under stress, as well as potential effects of common nutritional supplements. Learning Objectives 1. The audience will learn about the presentation, diagnosis, and/or treatment of an interesting Aerospace Medicine case. 2. The audience will learn about the similarities and differences in medical standards and pilot medical clearances for civilian, US and foreign military aviation professionals. [ABSTRACT FROM AUTHOR]

Spatial disorientation (SD) is one of the important causes of critical aircraft mishaps. In these five years (2019-2023), Japan Air Self-Defense Force (JASDF) has lost three fighter pilots due to mishaps. The Accident Investigation Board concluded that one of the causes of these mishaps was unrecognized SDs. Since then, JASDF decided to start SD training for duty fighter pilot using the SD Trainer (GL-4000, ETC, USA.). But, there is no clear evidence whether the SD training would be effective for pilots to recognize SDs during flight. To evaluate the effectiveness of SD training, we asked the trainees of SD training to participate in the questionnaire survey. The SD training consists of the 1-hour lecture and SDs experience by SD Trainer. The questionnaire was answered while the trainees had been engaged in the ordinary flight duties approximately 3 months after SD training. Among 234 research participants, we received 32 answers and analyzed them (as of October 31, 2023). 13 pilots (40.6%) experienced the actual SDs after SD training and most of them (11; 34.3%) felt it is easy to recognize SDs compared to before. Especially, some of them answered their SDs would induce the severe mishap unless they could recognize them. However, some pilots (2; 6.25%) could not realize the effectiveness of SD training. SD training was seemed to be potentially effective to easily recognize SDs during flight, but effectiveness of singletime training might be limited. To prevent the severe mishaps related to SDs, it would be important to establish the system to undertake SD training repeatedly. Learning Objectives 1. The audience will learn about the Spatial Disorientation Training On ground how effect to recognize the SD in flight. 2. The audience will learn about the SDs' episode in JASDF in flight. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Fighter pilots are routinely exposed to high levels of oxygen. The U.S. Navy uses the on-board oxygen generating system's maximum output, nominally 94%, at all altitudes. However, the effects of repeated exposure to the oxygen partial pressures (PO2) at this concentration have yet to be fully evaluated. This study explored some acute and cumulative effects of elevated PO2 compared to air. The PO2 of interest was that for 94% O2 at 8,000 ft above mean sea level, equivalent to 73% O2 in our laboratory. METHODS: This IRB-approved, between-subjects, single-blinded study included 57 healthy adults ages 19 to 44 (median 29) years. Participants were randomized into two groups, 73% O2 or 21% O2. Participants completed five consecutive days of testing with a twohour seated gas exposure in each of the first four days. Measurements were respiration during the exposures, grip strength, ventilatory response to exercise, spirometry, lung diffusing capacity, orthostatic tolerance, plasma erythropoietin concentrations, and a set of inflammatory markers. Each exposure day included pre- and post-tests of one variable. Not all variables were tested each day. RESULTS: Two-way, repeated measures ANOVA examined the effects of O2 condition and time. Variables not listed here showed no significant effects. No interactions of time and condition were found. End-tidal CO2 (etCO2) showed a main effect of condition, F(1, 47)=14.571, p<.05; participants exposed to 73% O2 had etCO2 levels 8.7% lower than did those breathing air. Main effects of time were found for ventilatory response to exercise (minute ventilation per O2 uptake rate, V'E/V'O2) [F(3, 141)=4.020, p<.05] and for some spirometry variables. V'E/V'O2 increased with time for both O2 conditions. The spirometry variables decreased over time for both O2 conditions while remaining within normal standardized ranges. DISCUSSION: The results indicate no acute or cumulative difference between O2 conditions other than on etCO2. Participants exposed to 73% O2 hyperventilated slightly, as anticipated, without signs or symptoms. Time effects on spirometric variables and V'E/V'O2 may indicate fatigue or prolonged sitting, not O2- related inflammation. Overall, the evidence indicates that repeated acute hyperoxic exposure has no substantive effect on the measured factors imperative to mission success. Learning Objectives 1. This experiment explored exposure to acute hyperoxia as relevant to aviation and suggested that those conditions do not have a substantial effect on the measured physiologic factors. 2. This experiment suggested that pulmonary inflammation is not evident after single or repeated two-hour hyperoxic exposures to a PO2 of 500 Torr (94% O2 at 8,000 feet MSL). [ABSTRACT FROM AUTHOR]

In northern regions, air convection embankment (ACE) has been implemented to mitigate road subsidence caused by permafrost degradation. The seasonal snow cover largely alters the surface energy balance and adversely affects the thermal stability of the road. However, thermal characteristics of a closed ACE and the quantification of their impacts on talik development remain largely unknown, especially in the present and future context of global warming. Here, impacts of snow cover on the pattern and strength of the air circulation were investigated and quantified. Snow cover greatly weakened the cooling effect of the closed ACE side slopes. The pore air velocity of the crushed-rock layer was reduced by half and the mean annual heat flux increased by approximately 1.6 W/m2, in comparison to the snow-free case. Conversely, the U-shape closed ACE had a better cooling performance due to a stronger air convection in winter, which increased heat loss from the snow-free surface of the embankment center. Our simulations suggest that the U-shape ACE embankment is a potential long-term solution to mitigate permafrost thaw over the life service (50 years) of road embankments in sub-arctic regions. The net results of this study are imperative to improve engineered design and road maintenance in cold regions. Our manuscript presents three important novel findings:1) Snow cover weakened the cooling effect of the closed ACE side slopes and causes the accelerated and potentially irreversible permafrost thaw.2) Pore air velocity of a closed ACE side slope with a snow cover was reduced by a half and the mean annual heat flux was increased by approximately 1.6 W/m2 compared with the snow-free case.3) High pore space connectivity of a closed U-shape ACE enhanced the air movement and increased heat extraction. [Display omitted] • Total heat loss from a side slope ACE and a U-shaped ACE was quantified. • Snow cover weakened the cooling effect of the closed ACE side slopes. • Pattern and velocity of air flow in the ACEs were quantified. • Snow insulation triggered permafrost thaw and talik development. • High pore space connectivity of a closed U-shape ACE enhanced the air movement. [ABSTRACT FROM AUTHOR]

Using newly collected data on death rates and aerial victories of more than 5,000 German fighter pilots during World War II, we examine the effects of public recognition on performance and risk-taking. When a particular pilot is honoured publicly, both the victory rate and the death rate of his former peers increase. Fellow pilots react more if they come from the same region of Germany, or if they worked closely with him. Our results suggest that personal rivalry can be a prime motivating force, and that non-financial rewards can lead to a crowd-in of both effort and risk-taking via social connections. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Physiological episodes are an issue in military aviation. Some non-pressure-related in-flight symptoms are proved to be due to hyperventilation rather than hypoxia. The aim of this study was to validate a new training method provoking hyperventilation during normobaric hypoxia (NH) training in an F/A-18 Hornet simulator. METHODS: In a double-blind setting, 26 fighter pilots from the Finnish Air Force performed 2 setups in a WTSAT simulator in randomized order with full flight gear. Without the pilot's knowledge, 6% O2 in nitrogen or 6% O2 + 4% CO2 in nitrogen was turned on. Ventilation (VE) was measured before, during, and after hypoxia. Spo2 and ECG were monitored and symptoms documented. The subjects performed a tactical identification flight until they recognized symptoms of hypoxia. Thereafter, they performed hypoxia emergency procedures with 100% O2 and returned to the base with a GPS malfunction and executed an instrument landing system (ILS) approach with the waterline HUD mode evaluated by the flight instructor on a scale of 1 to 5. RESULTS: Ventilation increased during normobaric hypoxia (NH) from 12 L · min−1 to 19 L · min−1 at Spo2 75% with 6% O2, and from 12 L · min−1 to 26 L · min−1 at Spo2 77% with 6% O2 + 4% CO2. ILS flight performance was similar 10 min after combined hyperventilation and hypoxia (3.1 with 6% O2 + 4% CO2 and 3.2 with 6% O2). No adverse effects were reported during the 24-h follow-up. DISCUSSION: Hyperventilation-provoking normobaric hypoxia training is a new and well-tolerated method to meet NATO Standardization Agreement hypoxia training requirements. [ABSTRACT FROM AUTHOR]

"Hit my smoke: Australian pilots targeting the enemy in Vietnam" is a book that tells the story of 36 Australian airmen who served as airborne Forward Air Controllers (FAC) in Vietnam from 1966 to 1971. The FACs were responsible for directing the precise delivery of aerial ordnance by tactical strike aircraft against enemy targets while ensuring the safety of friendly forces. The book, written by Peter Condon with Chris Clark, was first published in 1997 and revised in 2021 to include additional material from Peter Condon and the accounts of six airmen. It provides firsthand accounts of the pilots' experiences and the intensity of their missions. The book is well-written, easy to read, and includes photographs. It would be of interest to readers interested in military history and provides a unique perspective on Australian participation in the Vietnam War. [Extracted from the article]

BACKGROUND: Occupational hazards facing high performance aircraft pilots ("fighter" pilots) can cause injury, time lost from flying, and voluntary or involuntary career termination. The high cost of training and retaining fighter pilots has spurred interest in the cost effectiveness of preventative and rehabilitative health solutions. METHODS: We investigated the potential cost effectiveness of a 5-yr, $24.9M U.S. preventative health program using equivalent annual worth (EAW) analysis. The program benefits were assessed with a combination of actual and estimated medical cost data and projected pilot retention improvement rates. Sensitivity analysis of variables such as discount rate, medical cost avoidance, and pilot retention improvement rate was conducted. RESULTS: Annualized costs of approximately $5M U.S. were used as the basis of comparison for annualized benefits. A medical cost database was searched to find expected annual direct medical (outpatient) costs related to injury of roughly $531K U.S. for the pilots covered by the program. Using Centers for Disease Control recommendations, approximately $4.7M U.S. was estimated to be the annual work loss cost. The program would presumably reduce a significant portion of these annual costs, but not all. Assuming various proportions of reduced costs by the program, the EAW was found to be consistently negative. However, when pilot retention improvement is included, EAW is positive using conservative assumptions. DISCUSSION: While outpatient and work loss costs will unlikely be completely covered by preventative health programs in this context, a minor improvement in pilot retention (about 1-3 additional retentions per year) produces a net positive annual benefit. [ABSTRACT FROM AUTHOR]

This article analyzes the combat emotions of Royal Norwegian Air Force Fighter pilots (hereafter RNoAF) during their bombing campaign over Libya in 2011. Using grounded theory in our interviews with them, we identified 12 categories of their emotions and behaviors, with variations in pride and fear emerging as the two key themes. We show how those two emotions thread through the literature of emotions in combat, and show further how our data, and the resulting matrix from an analysis of it, both apply to and extend that literature. We also show how the high and low variations of pride and fear interact to both support and counter each other. Our findings thus make an important contribution to the combat emotions literature on the action and behavior of fighter pilots. [ABSTRACT FROM AUTHOR]

This paper presents the development of a dynamic Active Noise Control (ANC) algorithm aimed towards reducing the broadband noise inside the helmet earcups of a fighter aircraft pilot helmet. The dynamic ANC involves a Variable Step-Size Griffiths (VSSG) FxLMS algorithm to attenuate noise entering directly through helmet, a LMS based adaptive noise canceller to attenuate noise entering through the pilot microphone, and energy detectors for failure protection and optimized battery power usage. The algorithms are implemented on Texas Instruments’ TMS320C6748 processor and are tested in a helmet ANC experimental setup. [ABSTRACT FROM AUTHOR]

Abstract Background Pain and impaired function in the cervical region are common in Air Force personnel (AFP), but evidence is limited regarding the thoracic region. This cross-sectional cohort study examined associations between cervico-thoracic pain and physical performance among Swedish AFP and explored possible differences and similarities in test performance between fighter pilots (FP), helicopter pilots (HP) and rear crew (RC). Methods AFP (n = 73) from one airbase performed eight tests of movement control of the spine, active cervical range of motion (ROM) in all six directions and isometric strength and endurance of the cervical flexors and extensors. The association between test performance and cervico-thoracic pain (based on the ‘Musculoskeletal screening protocol’ questionnaire) were analysed in a multiple binary logistic regression model. Results For AFP with cervico-thoracic pain (30%), movement control was impaired in the ‘neck flexion test’ (OR [95%CI] =3.61 [1.06–12.34]) and the ‘forward lean test’ (OR [95%CI] =3.43[1.04–11.37]), together with reduced flexion ROM (OR [95%CI] =0.93 [0.87–0.99]). Test performance was in general similar between the three groups, but FP and HP could control the ‘forward lean test’ to a significantly higher degree than RC (p = 0.000). Further, FP showed significantly greater ROM in lateral flexion to the right compared to HP and RC (mean: 40.3°, 36.2° and 33.4°, respectively, p = 0.000), and they showed higher, although not significant, flexor strength than RC (p = 0.026). Conclusions The impaired function associated with cervico-thoracic pain highlights the need for a deeper understanding of such relationships when designing tools to systematically optimize the physical performance and prevent pain among AFP. Studies with a longitudinal design are warranted to examine any causative associations between pain and impairments.