Fatigue Management Training for Maximum Endurance Flight in the Mobility Air Force Published July 16, 2026 By Maj. Ross Jensen et al Future combat operations in the Pacific will require the readiness of Mobility Air Forces (MAF) to operate on flight duty periods (FDPs) up to 48 hours in duration—double the current regulatory limitation of 24 hours.[1] These 24-to-48-hour sorties, or “maximum endurance operations” (MEOs), result in longer FDPs and elevate aircrew fatigue risk.[2] As MEO requirements have emerged, the MAF has not yet developed a corresponding fatigue management (FM) training program. This is a gap worth closing. FM training programs have been demonstrated to meaningfully reduce fatigue risk, making them a practical and proven tool for preparing crews for the demands of extended FDPs.[3] This paper argues that such a training program should be adopted and that programs from analogous communities provide a practical basis to define the training’s content, audience, and timing of delivery. Background The MAF’s requirement to operate up to 48-hour FDPs is grounded in emerging operational realities, particularly in the Indo-Pacific. MAF operations in the Pacific during wartime would be characterized by extreme distances, compressed timelines, and demand that might outstrip airlift capacity. As General Mike Minihan, former commander of Air Mobility Command (AMC) argued, mobility forces could become the most relied-upon-force in the history of modern warfare, an assessment underscoring the scale of the expected tasking.[4] These conditions may necessitate MEOs to sustain the fight at the speed of need during a contingency. MEOs incur additional risk but are not without safe precedent. In 1929, a Fokker C-2 with a crew of five flew continuously for over 150 hours.[5] Opening actions of Operation ENDURING FREEDOM included strikes by B-2s departing Whiteman AFB and flying non-stop to Afghanistan on a 44-hour mission.[6] More recently, B-2 strikes in Operation MIDNIGHT HAMMER consisted of 37-hour nonstop flights.[7] Yet, while precedent for MEO-like FDPs exists and the current problem set necessitates these longer duty periods, the MAF has yet to establish aircrew fatigue training which might reduce the risk of these operations.[8] Fatigue Management and the Utility of Training While it is impossible to eliminate fatigue from MEOs, fatigue risk can be effectively managed with the help of a training program.[9] This is evidenced by precedent within the aviation community demonstrating the value of FM training. For example, a research study, in which B-1 crews flew three simulated 36-hour missions, showed marked performance improvements on the second and third missions compared to the first.[10] The study also found that common fatigue-related effects, including subjective tension, anger, and confusion, were markedly reduced after the first mission. Based on these results, the study’s authors concluded units should implement training to minimize risk, especially before an aircrew’s first long-duration mission. In this regard, fatigue training can be beneficial in a similar way aircrew train for hypoxia using a Reduced Oxygen Breathing Device—building familiarity with the symptoms, setting realistic expectations, and helping crews anticipate how they are likely to think and behave under impairment. An Approach to MAF Fatigue Management Training This research conducted a deductive thematic analysis of data from two airlines, the B-2 community, 19 AF’s Comprehensive Readiness Aircrew Training (CRAFT), the International Air Transport Association (IATA), the U.S. aviation company Jeppesen, and the Civil Aviation Safety Authority (CASA) of Australia. The purpose of this analysis was to derive insights into key elements that an FM training program should include. From this analysis, six themes were identified that provide a practical basis for the program’s development. These themes can inform the training’s content, audience, and timing of delivery. The following discussion details these themes. Theme 1: FM training should educate aircrew on science underlying fatigue Sleep science emerged as the most prevalent topic in the reviewed FM training programs. Sleep science content commonly covered sleep quantity and quality, circadian rhythms, sleep stage architecture (REM and non-REM), and relevant biopsychosocial factors (e.g. age), along with how fatigue manifests in aircrew. Given its dominance in the analyzed training content, this study recommends a MAF FM training program prioritize types of sleep and non-REM/REM cycles, circadian rhythms, the sleep homeostatic process, and how these systems interact with operational factors. Recommendation: Provide instruction on types of sleep and the non-REM/REM cycle There are two “types” of sleep—non-REM and REM.[11] Across a normal night of sleep, these types alternate in repeating non-REM/REM cycles.[12] Sleep typically starts in lighter stages of sleep, and subsequently enters into deep sleep approximately 30 minutes after falling asleep.[13] After 80 to 90 minutes of sleeping, a person transitions from deep sleep to the first period of REM sleep.[14] Over the course of a night this cycle repeats, with each subsequent cycle having more REM sleep and less deep sleep.[15] Understanding this cycle matters because it builds individual knowledge of the restorative value of sleep and provides a practical basis for planning naps and rest opportunities. Recommendation: Provide instruction on circadian rhythm With this foundation in how sleep is structured, FM training should then explain underlying human processes resulting in fatigue, beginning with the circadian rhythm. The circadian rhythm is a pacemaker in the brain monitoring day-night cycles driving the body’s preference for sleeping at night and increased activation during the day.[16] As a result, alertness follows a predictable daily pattern, typically peaking in the late afternoon and reaching its lowest point in the pre-dawn hours.[17] The circadian rhythm poses a fatigue challenge for flight operations in two ways. First, when flights occur at night—during a period the circadian rhythm strongly promotes sleep—aircrew may remain aligned to the local day-night cycle.[18] Consequently, they should expect increased sleepiness and fatigue symptoms on night flights, to include a greater risk of microsleeps.[19] For these reasons, most fatigue-related mishaps occur at night when the circadian rhythm is at its lowest point.[20] Secondly, a disruption of the circadian rhythm contributes to jet lag. Jet lag occurs when trans-meridian travel produces misalignment between internal circadian time and the local light-dark cycle, and it is most likely when aircrew cross multiple time zones within a single FDP.[21] For example, a crew might depart on a long-haul westbound mission and, after multiple time-zone crossings, spend much of the cruise phase operating in darkness. This misalignment can degrade performance both during the FDP and after its completion. Recommendation: Provide instruction on the sleep homeostatic process In addition to the circadian rhythm, the sleep homeostatic process is another physiological driver of fatigue symptoms.[22] This process can be described as accumulation of sleep pressure throughout the day that, after reaching a certain threshold, results in sleepiness. More simply, the longer individuals are awake, the more homeostatic sleep pressure exists, and they will feel more tired as a result. The only way to dissipate homeostatic pressure is through deep sleep, from either napping or a full night of rest.[23] If crewmembers are coming off a previous night of inadequate sleep quality or quantity, they can be expected to be more susceptible to fatigue resulting from homeostatic pressure build-up during the FDP.[24] For example, if a crew is flying a night mission and they awoke during a natural circadian time in the morning, by the time the crew flies the following night they will have been awake for many hours. This means the crew is beginning their FDP at a heightened homeostatic sleep pressure and at a heightened risk of fatigue.[25] Recommendation: Provide instruction on how sleep science interacts with operational factors A way to understand the practical implications of aircrew fatigue on a given mission is to view fatigue risk as a function of operational factors interacting with individuals’ circadian rhythm and homeostatic processes. Several operational factors contributing to fatigue have been identified in studies, including sleep deprivation, early wakeups, time pressure, multiple legs during a single mission, consecutive FDPs without a recovery, night flights, jet lag, inadequate rest facilities, and ineffective scheduling.[26] Many of these factors increase time awake and elevate homeostatic sleep pressure, shift operations to circadian low points, or do both—creating a compounded fatigue risk. These operational factors offer practical lenses FM training might leverage to frame how the MAF should conceptualize and manage fatigue problems. For example, lessons could demonstrate how a given flight's route and timing interact with local day-night cycles and consequently affect the post-mission recovery period.[27] Theme 2: FM training should include FM-related policy education A second prevalent theme in our analysis was the importance of clearly communicating organizational policies governing FM. “Policies” here include FDP limitations, organizational fatigue reporting, and organizational fatigue risk management procedures. Additionally, for airlines this subject encompasses teaching the concept of “just culture”—an organizational culture promoting self-disclosure of errors, and allowing for due consideration of honest mistakes, especially in complex environments.[28] Recommendation: Provide instruction on safety reporting, and use relevant examples from these reports In addition to fatigue-related rules and limitations, FM training should emphasize safety reporting. The MAF already has mechanisms in place to facilitate a just culture. The Aviation Safety Action Program (ASAP) is a channel for aircrews to report safety-related incidents in a protected, non-punitive manner. Fatigue-related reports would serve as realistic training examples. This proposal would be in-line with IATA’s recommendation to include instruction on the role of fatigue in safety-related incidents. Therefore, application of this theme to MAF FM training would be to provide clear explanations of reporting pathways and protections, while also incorporating fatigue-related case examples drawn from reporting data. Recommendation: Deepen understanding of crew complement’s impact In addition to reporting, FM policy should address assumptions embedded in crew augmentation and crew complement decisions. Organizations should not add additional aircrew without an evidence-based plan for how augmentation will improve fatigue risk.[29] In general, in-flight sleep quality and quantity is poor and additional allocated bunk time does not reliably translate to actual additional sleep.[30] Research on ultra-long range airline flights shows, even when aircrew were allocated seven rest hours, actual sleep time was less than 50% of time allotted.[31] While the ideal MEO crew size is outside the scope of this study, this underscores the need for the chain-of-command and scheduling apparatus to receive FM training improving understanding of the relationship between crew complements and fatigue during extended FDPs. Theme 3: FM Training should include behavioral measures countering fatigue If Theme 1 and Theme 2 lay the foundation for understanding the fatigue problem, Theme 3 answers the question, “What can we do about it?” Fatigue mitigation techniques can be grouped into two complementary approaches: preventive strategies and operational countermeasures.[32] Preventive strategies are longer-term, planned actions before and after FDPs, such as organizational scheduling practices and crew management.[33] In contrast, operational countermeasures are short-term actions taken during FDPs aimed at reducing sleepiness and enhancing alertness.[34] For the purposes of the following discussion, “preventive strategies” refers to actions before and after FDPs. “Operational countermeasures” refers to actions taken during FDPs. Both are important components of FM. Recommendation: Provide instruction on preventive strategies A fundamental preventive strategy should be to instruct smart scheduling practices. Within the data set, subject matter included instruction on purposeful scheduling practices addressing fatigue. These practices include identifying disruptive schedules relative to crews’ circadian rhythm, as well as considerations for aircrew FDP extensions, re-tasking aircrew to new missions, or placing aircrew on standby/alert duty. Additional preventive strategies also include long-term individual behaviors, such as adjusting sleep schedules, pre-duty napping strategies, nutrition, exercise, and the use of No-Go medication. Strategies for aircrew adaptation after trans-meridian travel should be taught to assist recovery from the previous FDP and rebound for the next FDP. Multiple strategies are recommended to assist the aircrew resynchronization process, to include properly-timed bright light[35] and other naturally occurring circadian cues like eating, socializing, and exercising to adjust their bodies to the new desired active time of day.[36] Recommendation: Provide instruction on operational countermeasures, to include in-flight sleep This study’s data analysis found that organizations teach operational countermeasures including discussions on controlled cockpit rest, in-flight napping, various types of stimulant use, use of well-timed rest or activity breaks, nutrition, hydration, and techniques for aircrew to monitor one another for signs of fatigue. Among these operational countermeasures, in-flight sleep warrants detailed examination for the purposes of MAF FM training.[37] Two common in-flight sleep countermeasures are controlled cockpit rest and bunk sleep, and both methods have been shown effective in attenuating fatigue effects.[38] Controlled cockpit rest is where one of two pilots at a set of controls may nap up to a maximum of 45 minutes at a time during non-critical phases of flight.[39] Research shows short naps in the pilot seat produced an average of 26 minutes of sleep during a 40-minute rest period.[40] When compared to pilots without a nap, this nap period objectively improved vigilance in test subjects and significantly reduced occurrences of microsleep in the final, critical portion of the flight. Moreover, these naps are short enough to avoid subsequent grogginess, and provide significant benefit for pilots flying the next critical phase of flight.[41] Bunk sleep is the second in-flight sleep countermeasure of note. Ideal duration for bunk naps is 2-4 hours, allowing for roughly two non-REM/REM sleep cycles including periods of deep sleep, which help blunt rising homeostatic pressure.[42] As previously noted, aircrew do not typically sleep longer than this duration in one bunk period.[43] While bunk sleep is usually of lesser quality than standard sleep, aircrew can still leverage this sleep period to partially attenuate homeostatic pressure.[44] In-flight sleep quality is reduced by noise, turbulence, temperature, and lighting.[45] Inclusion of these factors in FM training would facilitate aircrew in more effectively considering countermeasures. Aircrew chains-of-command might also use this information to procure equipment mitigating these impediments to sleep quality (e.g. eye masks to block light, ear protection to minimize sound, mattresses or sleeping bags to improve sleep comfort, etc). Recommendation: Provide instruction on practical approaches to in-flight work-rest plans A critical policy tool to manage fatigue is known as in-flight rostering--commonly referred to as the aircrew’s “work-rest plan”. This is an in-flight schedule detailing when individual aircrew are allocated specific times for sleep. The work-rest plan’s goal is to systematically place nap windows throughout FDPs to ensure crewmembers are not performing critical phases of flight after periods of extended wakefulness.[46] While the specific definition of “critical phase of flight” varies by aircraft type, for MAF this generally includes terminal area operations including taxi, takeoff and landing, low-level flight, air refueling, and airdrop.[47] However, work-rest plans are only effective if developed during flight planning, aircrew is educated, and aircrew adheres to the plan in-flight.[48] Construction of an adequate work-rest plan should be given careful consideration in planning due to the complexity associated with multiple critical phases occurring throughout the FDP, and the potential layering of timed use of pharmacological agents. Recommendation: Practice crew resource management under fatigue conditions An FM training program specifically focusing on crew resource management (CRM) would aid in mitigating fatigue risks. CRM is the effective use of all available resources (e.g. people, aircraft systems, facilities, equipment and environment) to safely and efficiently accomplish an assigned mission or task.[49]A recent study of three fatigue-related aircraft crashes arrived at similar conclusions; namely there is a pressing need to train pilots on communication and decision-making under fatigued conditions. While fatigued, aircraft pilots in command (PICs) demonstrated lack of leadership, insufficient management of contingency situations, inadequate briefing, and deficient workload management.[50] While these topics are not foreign to MAF aircrew, they deserve special attention during a MEO, as crew coordination is likely to suffer as they experience fatigue. This is further supported by the NTSB, which reported errors by the pilot monitoring (PM) as pervasive during crew-involved major accidents between 1978 and 1990.[51] During major accidents, 90% of the errors PMs failed to challenge were either causal or contributing factors to the accident. Most errors by the PM were failing to challenge an error of omission by the PIC.[52] Thus, it can be concluded in fatigue-related crashes, crew coordination, and specifically communication break-downs, are common contributors. However, CRM training for MEOs should extend beyond introductory communication skills, and cultivate more precise strategies for conveying information effectively, especially when operating fatigued. For MAF crews, policy requires crewmembers to notify the pilot in command when they become fatigued.[53] But, considering individuals are often poor judges of their own level of alertness, awareness of high levels of fatigue may not become self-evident until after errors occur.[54] In these situations, more “critical” communication should occur. Critical communication is a modality of team communication, characterized by high levels of brevity and clarity, occurring when urgent or emergent problems arise that constrains available time to act.[55] This type of communication is common in medical operating rooms, where tone, tempo, volume, and many of the accepted characteristics of routine communication are ignored.[56] The same principles of team-based critical communication that achieve desirable patient outcomes are relevant to aircrew managing emergent in-flight problems, and should be considered for codification in MAF FM policy and training. Recommendation: Integrate technology to enhance fatigue feedback Recent advances in health monitoring technology support development of useful fatigue management tools. Mobile, application-based tools providing tailored feedback and advice regarding exposure to daylight, sleep, physical activity, and nutrition have demonstrated the ability to significantly improve aircrew fatigue levels.[57] AMC is presently exploring an array of wearable technology to track and optimize human performance characteristics during MEO. New and improved fatigue modeling tools are being developed for extended FDPs. However, it stands to reason that a FM training program is a prerequisite to effective use of any of these tools. Theme 4: FM training should be organization- and MDS-specific This theme identifies that content within an FM program should conform to the specific mission and objectives distinctive to a given mission design series (MDS).[58] Any FM program should allow enough flexibility to account for unique operational characteristics germane to each MDS community, even if it is uncommon in conventional FM training programs.[59] For the MAF, an example of such a novel requirement is illustrated by the need for 48-hour multi-stop FDPs with several crewmembers to manage. The B-2 provides a demonstrative case of this concept in their community’s use of a long-duration Weapons System Trainer, which is the centerpiece of its Long Duration Qualification Training (LDQT). LDQT is an event where aircrew execute simulated missions lasting a minimum of 24 hours. The event emphasizes ground testing of Go-Pills, in addition to practicing other pre- and in-flight countermeasures. For these reasons, a similar long duration simulator event might be of interest to MAF. But more broadly, MDS-specific training could be included in MAF FM in areas like in-flight work-rest planning for augmented crews, CRM exercises, and Go-Pill usage. Recommendation: Consider benefits and implications of stimulant and hypnotic use A more in-depth education on pharmacological stimulants (Go Pills) and hypnotics should be addressed to mitigate the unique operational characteristics of a MEO. One challenge of operationalizing Go Pills are dealing with common misconceptions and stigma.[60] FM training should objectively inform target audiences and dispel Go Pill misconceptions by describing benefits, risks, and the most-effective use of both Go Pill options: Dextroamphetamine and Modafinil. An illustrative example from a recent campaign shows how a de-stigmatized training focus on stimulants could provide improved FM results. For B-2 long-duration missions flown during Operation Iraqi Freedom, 97% of pilots reported benefitting from Dextroamphetamine use, with only 6% reporting experiencing jitteriness.[61] Meanwhile, in the same study one pilot was documented as using 2.9g of caffeine within a single FDP, an amount more than 7 times what the FDA considers safe for daily consumption in adults. In this instance, a stigmatized FM tool (Dextroamphetamine) was used safely and effectively in low doses; meanwhile, a tool with greater social acceptance (i.e. caffeine) was used in excessive and unsafe amounts. A similarly stigmatized substance, nicotine is shown to sustain monotonous task performance and produce improved cognitive function, in both speed and accuracy of information processing.[62] Tobacco use is prohibited on all USAF aircraft; however, multiple non-tobacco nicotine options exist which could be used to maintain increased alertness (e.g. nicotine pouches or nicotine gum).[63] Effective MEO FM training should present evidence-based information on all available countermeasures without exception. Where stigma exists around tools like Dextroamphetamine, training is the appropriate venue to replace assumption with data. Theme 5: FM training should be a whole-of-organization requirement FM training should not just be targeted at aircrew who operate during MEO missions. Rather, the entire organization has a role in mitigating fatigue, and should therefore receive FM training. At U.S. airlines, FM training’s mandated audience is described in 14 CFR Part 117. This regulation requires aircrew, dispatchers, flight crew schedulers, individuals involved in operational control, and any other employee providing direct management oversight of these areas to receive FM training. This multi-stakeholder requirement was consistent with the international airline in our data set, which requires FM training for flight crew, managers, schedulers, and anyone else with direct responsibility within the company's fatigue risk management system. Comparing this to the military organizations we examined (the B-2 and 19 AF’s CRAFT program), both accomplish FM training; however, neither mandate FM training for personnel other than aircrew. This likely reflects the reasonable assumption that aircrews’ chain-of-command and scheduling functions typically consist of other aircrew members. However, the MAF’s unique operational profile, including multi-stop FDPs, larger crew complements, and global scheduling complexity, argues for a broader training audience. Recommendation: Broaden the target audience of FM training FM training for MEO should extend beyond affected aircrew. To enhance FM program success, personnel at multiple organizational levels should be educated and trained on fatigue hazards and mitigation.[64] ICAO guidelines explicitly require FM training for aircrew, schedulers, fatigue safety action group, those responsible for operational risk assessment and resource allocation, and senior management. Applied to MAF, this would equate to aircrew, the entire scheduling apparatus, the safety apparatus, and the chain-of-command receiving FM training. Similarly, in Europe airlines are mandated, to conduct both initial and recurrent FM training for aircrew, personnel responsible for preparation and maintenance of crews, and management functions.[65] A particular FM training emphasis should be placed on those responsible for flight scheduling. Scheduling factors are often cited as top contributors to pilot fatigue.[66] If sleep-wake cycles and duty periods are not properly managed by MAF units, they should expect a negative impact to aircrew operational readiness.[67] A 1992 case study of Navy pilots operating during aircraft carrier operations in Operation Southern Watch illustrates this point. Poor sleep-wake management by unit schedulers resulted in a majority of scheduled pilots reporting negative performance impacts and fatigue, which manifested in headaches, alertness difficulties, and falling into uncontrollable sleep during flight.[68] Theme 6: FM training should be accomplished both initially and recurrently This theme addresses timing which personnel within MAF might receive FM training preparing them for MEO. For organizations administering FM training, initial training commonly occurs early in employment. For example, the international airline accomplishes classroom training within the first six months of employment, while the US airline administers FM training via CBT during initial flight training. Considering the military organizations, both 19 AF and the B-2 community include FM training in initial flying training. 19 AF directs 20.5 hours of FM training during Undergraduate Pilot Training, while the B-2 community places it directly after Initial Qualification Training. Additionally, recurrent training is common among airlines, and is often administered via CBT. The US airline examined in this study mandates annual training, in accordance with 14 CFR Part 117, while the international airline dictates recurrent training every two years. Notably, the military FM programs do not have a recurrent component. For example, the B-2’s LDQT is intended to be a one-time training to carry over for consecutive tours in the B-2.[69] The other military example studied here envisions a recurrent aspect, but lacks authority to mandate it. 19 AF’s FM syllabus implies the program’s vision is not intended to be a one-time event, but instead the start of a learning process beginning in Undergraduate Pilot Training and evolving through an Airman’s career. In an environment of competing currency demands and finite training time, if a MAF FM program is not explicitly mandated, it is unlikely to be instituted. Recommendation: Consider recurrent training and different training mediums The MAF should examine the means of FM subject-matter delivery at multiple points of aircrew development to achieve the greatest benefit. Research offers three different distinct mediums for teaching FM subject matter. First, training can be delivered by trained subject-matter experts, which can include supplementary material distributed for self-paced study.[70] A second alternative is use of mobile devices and wearable technology enabling individually tailored FM feedback.[71] Finally, flight simulation enabling long duration simulator training can allow crews to apply FM principles in simulated operations.[72] Each medium is useful at different points in the training and education process, and an ideal FM training program makes use of each. For example, a training program could use self-paced CBTs to introduce FM topics, then have an expert-led live session, followed by a long duration simulator profile where aircrew apply both individually tailored feedback and concepts taught in training. A final point regarding recurrent training is the need to practice good communication practices. To this end, lessons from the medical community might translate seamlessly to a MAF MEO context. As previously discussed, critical communication aids in error prevention and recovery while fatigued. The medical field makes extensive use of simulations, including specifically practicing non-technical CRM skills like task management, situational awareness, and teamwork in the context of high-risk environments. Applied to the MAF, simulation could allow for focus on applying CRM principles under fatigue conditions and would be a worthwhile contribution to an FM training program. Summary of Findings See Table 1 for a summary of the themes identified within the data, which describes these themes as they relate to the research questions. From these themes, a framework was developed to illustrate various components of FM training and how they comprehensively relate to reduce fatigue risk (Figure 1). Table 1. Summary of Themes Conclusion As the MAF prepares to meet the demands of maximum endurance operations, a formal FM training program is a logical next step. This study demonstrates that analogous communities have already solved this problem, and that their programs offer a research-grounded basis for MAF FM training development. The six themes identified here address content, audience, and delivery frequency, and provide MAF leaders a practical framework to act on. Building the syllabus, policy, and courseware is the next step. Maj Ross “SMOKE” Jensen, USAF, is a C-17 pilot and Airpower Strategist in the Strategy Division of Air Force Futures. He is a graduate of the USAF Weapons School, Air Mobility Command’s (AMC) Advanced Study of Air Mobility (ASAM) program, and the School of Advanced Air and Space Studies. He holds an MS in Operations Management from the Air Force Institute of Technology (AFIT) and an MPhil in Military Strategy from Air University. Lt Col Jacob Maywald, USAF is a Logistics Readiness Officer and an assistant professor at the AFIT’s Department of Operational Sciences. He holds a MS in Logistics and Supply Chain Management from AFIT, and a PhD in Logistics Systems from the University of North Texas. Lt Col Sean "SPAZ" McConville, USAF is a C-17 pilot and an assistant professor at the AFIT’s Department of Operational Sciences. He is a graduate of the USAF Weapons School, and AMC’s ASAM program. He holds an MS in Operations Management from AFIT, as well as a PhD in Logistics Systems from the University of North Texas. Col Ian "Slaz" Slazinik, USAF is a KC-135 pilot, the director of DIICE, and an assistant professor at AFIT’s Department of Operational Sciences. He holds a MS in Operations Management from AFIT, and a PhD in Logistics Systems from Auburn University. Lt Col Stephen “Hyper” Kasteler, USAF is a flight surgeon and Chief of Aerospace Medicine at the Special Warfare Human Performance Support Group. He holds an MD from the Uniformed Services University of the Health Sciences and an MPH from the Harvard T.H. Chan School of Public Health, where he also completed residency training in occupational and environmental medicine. [1] Paula Arce, “22 ARW Completes First 45-Hour Nonstop KC-46 Flight Around the World,” Air Mobility Command, U.S. Air Force, July 1, 2024; David Roza, “Mobility Pilots Prepare to Fight Fatigue in All-Out Pacific Conflict,” Air & Space Forces Magazine, January 2024. For this study “MAF” is used as an umbrella term encompassing C-130, C-17, C-5, KC-135, and KC-46 aircraft and crews. All references to duty length or Flight Duty Period (FDP) will be referring to the period between when aircrew first report for official flight duty and ending at final engine shut down of the mission in accordance with AFMAN 11-202 V3 AMC Supplement. [2] Megan B. Morris, Mark D. Wiedbusch, and Gerald Gunzelmann, “Fatigue Incident Antecedents, Consequences, and Aviation Operational Risk Management Resources,” Aerospace Medicine and Human Performance 89, no. 8 (2018): 708–16. [3] Mark R. Rosekind, Kevin B. Gregory, and Michael M. Mallis, “Alertness Management in Aviation Operations: Enhancing Performance and Sleep,” Aviation, Space, and Environmental Medicine 77, no. 12 (2006): 1256–65. [4] Gen. Mike Minihan, Commander, Air Mobility Command, remarks at AMC’s Human Performance Industry Day, personal communication, December 12, 2023. [5] Ellery Wallwork, “Flight of the ‘Question Mark,’” Air Mobility Command History Office, December 24, 2008. [6] Daniel Haulman, “44 Hours,” Air Force Magazine (2017): 33–37 [7] Eric Schmitt and Ronen Bergman, “For B-2 Pilots, a 37-Hour Nonstop Mission to Iran and Back,” New York Times, June 24, 2025 [8] Fatigue -- This study uses the International Civil Aviation Organization’s (ICAO) definition of fatigue, describing fatigue as “a physiological state of reduced mental or physical performance capability resulting from sleep loss, extended wakefulness, circadian phase, and/or workload that can impair a person’s alertness and ability to perform safety related operational duties.” International Civil Aviation Organization (ICAO), Fatigue Management Guide for Airline Operators (Montreal: International Civil Aviation Organization, 2015).; Specifically, aircrew duty length is noted as a major cause of fatigue. Morris, Wiedbusch, and Gunzelmann, “Fatigue Incident Antecedents,” 708–16; Torbjörn Åkerstedt, “Consensus Statement: Fatigue and Accidents in Transport Operations,” Journal of Sleep Research 9, no. 4 (2000): 395. [9] ICAO, Fatigue Management Guide for Airline Operators. [10] John French et al., “Crew Fatigue during Simulated, Long Duration B‑1B Bomber Missions,” Aviation, Space, and Environmental Medicine 65, no. 5 (1994): A1–A7. [11] ICAO, Fatigue Management Guide for Airline Operators. [12] ICAO, Fatigue Management Guide for Airline Operators. [13] ICAO, Fatigue Management Guide for Airline Operators. [14] ICAO, Fatigue Management Guide for Airline Operators. [15] ICAO, Fatigue Management Guide for Airline Operators. [16] ICAO, Fatigue Management Guide for Airline Operators.; Caldwell, “Fatigue in Aviation.” [17] Torbjörn Åkerstedt, “Work Hours, Sleepiness and the Underlying Mechanisms,” Journal of Sleep Research 4, suppl. 2 (1995): 15–22. [18] ICAO, Fatigue Management Guide for Airline Operators [19] ICAO, Fatigue Management Guide for Airline Operators; John Caldwell and J. Lynn Caldwell, Fatigue in Aviation.: A Guide to Staying Awake at the Stick (London: Routledge, 2016). Microsleeps are short periods of time when the brain disengages from the environment and slips uncontrollably into light non-REM sleep. [20] E. Gene Lyman and Capt. Harry W. Orlady, Fatigue and Associated Performance Decrements in Air Transport Operations, NASA Contractor Report 166167 (Mountain View, CA: Ames Research Center, National Aeronautics and Space Administration, 1981). [21] ICAO, Fatigue Management Guide for Airline Operators [22] The idea of a homeostatic process is associated with the concept of homeostasis. Homeostasis is how the body regulates internal systems so they function correctly by reaching and maintaining a state of balance. Homeostatic processes are automatic and result from the body sensing a change and trying to counteract or reverse the unwanted change. In this case of the sleep homeostatic process is a process of the body sensing the change in accumulation of sleep pressure and forcing a reversal through sleep. Cleveland Clinic, “Homeostasis,” last reviewed February 28, 2023. [23] ICAO, Fatigue Management Guide for Airline Operators [24] Caldwell, “Fatigue in Aviation.” [25] Caldwell, “Fatigue in Aviation.” [26] S. Bourgeois-Bougrine et al., "Perceived Fatigue for Short and Long Haul Flights: A Survey of 739 Airline Pilots" Aviation, Space and Environmental Medicine (2003) 74(10): 1072-1077; Sangyong Lee and Jae K. Kim, "Factors Contributing to the Risk of Airline Pilot Fatigue," Journal of Air Transport Management 67 (March 2018): 197–207. [27] Alexander Samel and Hans M. Wegmann, "Bright Light: A Countermeasure for Jet Lag?," Chronobiology International 14, no. 2 (1997): 173–83. [28] Federal Aviation Administration, “Compliance Program,” accessed February 16, 2026, [29] John A. Caldwell et al., "Fatigue Countermeasures in Aviation," Aviation, Space, and Environmental Medicine 80, no. 1 (2009): 29–59. [30] Caldwell et al., "Fatigue Countermeasures." [31] T. Leigh Signal et al., "In-Flight Sleep of Flight Crew During a 7-Hour Rest Break: Implications for Research and Flight Safety," Sleep 36, no. 1 (2013): 109–15.; P. Ho et al., "The Singapore Experience: Task Force Studies Scientific Data to Assess Flights," Flight Safety Digest 24, no. 8–9 (2005): 20–40. A ULR operation is one in which a single sector exceeds a scheduled flight time of 16 hours. In some cases, these FDPs can be up to 22 hours. [32] Mark R. Rosekind et al., Crew Factors in Flight Operations IX: Effects of Planned Cockpit Rest on Crew Performance and Alertness in Long‑Haul Operations, NASA Technical Memorandum TM‑108846 (Washington, DC: National Aeronautics and Space Administration, 1994). [33] Mark R. Rosekind et al., Crew Factors in Flight Operations X: Alertness Management in Flight Operations, report no. IH‑022 (2001). [34] Rosekind et al., Crew Factors in Flight Operations X [35] Samel and Wegmann, "Bright Light,"; [36] Josephine Waterhouse, Tim Reilly, and Greg Atkinson, "Jet-Lag," The Lancet 350, no. 9091 (1997). [37] Caldwell, “Fatigue in Aviation.” [38] Caldwell et al., "Fatigue Countermeasures." [39] AFMAN 11‑202V3 AMC Sup, Flight Operations. [40] Rosekind et al., Crew Factors in Flight Operations X [41] Rosekind et al., Crew Factors in Flight Operations X [42] Caldwell et al., "Fatigue Countermeasures."; ICAO, Fatigue Management Guide for Airline Operators. [43] Signal et al., "In-Flight Sleep,"; Ho et al., "The Singapore Experience,". [44] Mark R. Rosekind et al., "Crew Factors in Flight Operations XII: A Survey of Sleep Quantity and Quality in On-Board Crew Rest Facilities," NASA/TM-2000-209611 (2000); French et al., "Crew Fatigue,". 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