Nearly a fortnight ago today, FlyDubai flight 981 was preparing to land in Rostov-on-Don, Russia. However, after being hampered by high winds, the crew aborted their landing attempt. Two hours later, they tried again. Video footage shows the airplane nose-diving into the ground and exploding in a giant fireball. All 63 passengers and crew on board were killed. Although the local air safety watchdog is yet to release its findings, some are suggesting that fatigue may have been a contributor.

By one account, pilots are being “overworked” and “50% of the airline's workforce are suffering from acute fatigue.” The claim comes despite the fact that the airline’s scheduling practices fall within regulatory limits aimed at managing fatigue.

These limits are the product of four decades’ worth of scientific research. Millions of dollars were spent on initiatives dedicated to understanding pilot fatigue. The efforts were groundbreaking for their time, as researchers studied the effects of sleep loss and interruption on muscle activity and brain function. They found that when it came to fatigue on the flight deck, the conditions surrounding when pilots flew mattered as much as how long that they flew for. Safety regulators today leverage this information to keep the skies safe.

Restrictions are placed on everything from how many hours a day a pilot may work to how much time off that pilot must get between consecutive shifts. The total amount of annual flying hours permitted is also capped. With such stringent safeguards in place, why does fatigue continue to make headlines?

Fatigue has long been linked to deficiencies in sleep quality, sleep quantity and sleep opportunity. The science underlying regulatory limits considers how these factors impact a pilot’s ‘wakefulness state,’ scientific slang for mental alertness. The focus on alertness is near absolute. Of the hundreds of studies that examine pilot fatigue, an overwhelming majority relies on alertness tests as the measurement tool of choice.

Yet, as Dr. Atul Khullar, a Fellow at the American Academy of Sleep Sciences points out, “The extent to which these tests accurately predict how safely an airplane is flown is less clear.” This ambiguity raises questions about the applicability of the science used to justify regulatory limits. Overwork may lead to more errors on the job. Acute fatigue may reduce responsiveness in an emergency. Yet, airlines and regulators alike have no way of knowing because investigations into these issues are the exception rather than the norm.

Anecdotes do tell of sleepy captains forgetting to extend flaps before takeoff and weary first officers nodding off at the controls while in command. However, regulations must be based on methodologically sound research, not anecdotes, and as yet, the relevant research is lacking.

The 24/7 nature of the airline industry means workers will always face challenges when it comes to getting adequate rest. This explains why according to a National Sleep Foundation survey, more than one out of three pilots report that their work schedules do not allow adequate time for sleep and one out of two rarely or never get a good night's sleep on work nights.

Yet these figures, troubling as they may be, are hardly the fault of airlines. Airlines abide by the restrictions put forward by safety regulators and regulators rely on science to help define what these restrictions should look like. If the crash in Rostov-on-Don were ultimately linked to pilot fatigue, it would prove one thing. More regulation isn’t the answer. Better science is.