A B-2 crew straps in at Whiteman Air Force Base, Missouri. Thirty-six hours later, they will land at the same base, having crossed the Atlantic twice, refueled multiple times, penetrated the most heavily defended airspace in the Middle East, and dropped the heaviest precision bombs in the American arsenal. Between takeoff and landing, they do not leave the cockpit. There is no relief crew. There is no way to stop.

That is what a 36-hour combat mission does to the human body. And it is not an outlier — it is the operational tempo of Operation Epic Fury.

The Science of Running on Empty

The research is unambiguous. After 17 hours without sleep, cognitive performance degrades to the equivalent of a blood alcohol concentration of 0.05%. At 24 hours, it reaches 0.10% — legally drunk in every American state. Reaction times slow. Decision-making narrows. The brain begins to prioritise the most immediate task and lose awareness of the broader picture — a phenomenon researchers call “attentional tunnelling.”

For a pilot, attentional tunnelling is not an inconvenience. It is a potential death sentence. The ability to simultaneously manage navigation, weapons systems, threat awareness, communication, and fuel state is what separates a competent combat aviator from a disaster. Fatigue erodes exactly that capacity — the higher-order cognitive function that combat flying demands most.

Studies conducted by the U.S. Air Force School of Aerospace Medicine have shown that fatigued pilots make more errors on instrument approaches, respond more slowly to simulated threats, and are measurably worse at assessing risk. In a training environment, these errors are correctable. In combat, they can mean a missed threat, a dropped weapon on the wrong coordinates, or a midair collision during a night refueling.

What Epic Fury Demands

The air campaign against Iran has pushed crew endurance to its limits across every airframe in the inventory. B-2 crews are flying the longest combat missions in aviation history — 30 to 36 hours, nonstop, from the continental United States. KC-135 tanker crews are logging 18-hour refueling sorties, often at altitudes and in airspace where the threat of hostile action is constant. Fighter pilots at Gulf bases are flying multiple daily combat sorties, with turnaround times measured in hours rather than the days that peacetime training assumes.

Air Force Instruction 11-202 Volume 3 — the regulation governing flight operations — mandates a minimum of 12 hours of crew rest, including 8 hours of uninterrupted sleep opportunity, before a flight. But the same regulation includes provisions for combat waivers that allow commanders to reduce those minimums when operational necessity demands it. In a sustained campaign like Epic Fury, “operational necessity” is the default condition.

A Problem as Old as Air Combat

Pilot fatigue has been a known killer since the earliest days of military aviation. In World War II, the U.S. Army Air Forces discovered that bomber crews became measurably less effective after 25 combat missions — a finding that led to the rotation policies depicted in novels and films about the air war over Europe. In Vietnam, the demanding schedule of carrier-based operations contributed to accident rates that sometimes exceeded combat losses.

More recently, fatigue was identified as a contributing factor in multiple incidents during the wars in Iraq and Afghanistan, where the combination of long missions, irregular schedules, austere living conditions, and the chronic stress of operating in a combat zone created a fatigue environment that no amount of crew rest regulation could fully mitigate.

The pattern is consistent across every conflict: the longer a campaign runs, the more fatigued crews become, and the more the risk of a fatigue-related mishap rises. Epic Fury is now in its sixth week. The crews are tired. The mission does not stop.

Managing the Unmanageable

The Air Force is not blind to the problem. Stimulant use — specifically dextroamphetamine (“go pills”) — has been an acknowledged part of combat aviation pharmacology since at least the first Gulf War, though the practice remains controversial. More recently, the service has invested in fatigue-management software that models crew alertness based on sleep history, circadian rhythm, and mission timing, giving schedulers a tool to identify crews who are approaching dangerous fatigue thresholds before they fly.

But no software can solve a fundamental mismatch between what the mission demands and what the human body can sustain. When the target list requires 36-hour B-2 sorties and the tanker schedule requires 18-hour KC-135 orbits, the only real options are more crews, more aircraft, or accepting a level of risk that no one wants to talk about in public.

The machines can fly indefinitely. The people inside them cannot. That gap is where the danger lives.

Sources: USAF School of Aerospace Medicine, Air Force Instruction 11-202 Vol 3, Air & Space Forces Magazine, IFALPA Position Paper on Crew Fatigue in Conflict Operations