How new DGCA rules put human limits at the centre of air safety

The recent disruptions in India’s aviation sector, in particular IndiGo’s wave of flight cancellations, have placed the spotlight firmly on the new fatigue and rest norms developed by the Directorate General of Civil Aviation (DGCA).

The public frustration is understandable. The cancellations appear to have stemmed from IndiGo’s scheduling gaps and inadequate crew planning rather than any flaw in the regulations themselves. In this context, any temptation to dilute the new rules must be resisted.

Aviation safety is grounded in the inviolable principles of human physiology. The DGCA’s new framework introduces changes aimed at minimising fatigue. The weekly rest period has been increased from 36 to 48 hours. The number of night landings permitted per pilot has been reduced from six to two, and the definition of night duty has been expanded to restrict flying during biologically unsuitable hours.

Limits on consecutive night duties, mandatory fatigue risk reporting, enhanced roster oversight, and regulated transition timelines are also part of the updated structure.

These modifications mirror global practices adopted by regulators in the US and Europe after mounting evidence demonstrated that fatigued pilots were often implicated in near-miss events and operational errors. In Europe and North America, rules limiting duty hours and mandatory rest have already reduced fatigue-related incidents.

Advances in aviation engineering have allowed aircraft to operate in a wide range of demanding environments. But as humans evolved to function on the ground, the regulations need to help people adapt to the unique stresses imposed during flight, such as lower atmospheric pressure, lower temperatures, and the physiological effects of acceleration on the body.

Pilots regularly work across time zones, often intensely so in the day’s twilight hours, and often have overnight schedules as well. All these demands destabilise the body’s intrinsic circadian rhythm. Disrupting this rhythm alters melatonin secretion, delays the onset of sleep, and leads to more and more sleep debt.

The immediate physiological effects of these changes include slower reaction time, lower vigilance, impaired judgment, intermittent microsleeping, emotional irritability, and difficulty in sustaining attention. Visual strain, dry cabin air, dehydration, vibration, and noise can further intensify cognitive fatigue.

Research has also associated chronic circadian misalignment with higher blood pressure, metabolic disturbances, lower immunity, higher risk of mood disorders, gastrointestinal dysfunction, and higher cardiovascular risk. Long-haul operations create persistent jet lag and irregular meals disrupt metabolic regulation. More hours in confined postures can also feed musculoskeletal strain. Taken together, these stresses should only be expected to cause more errors during flight. Indeed, fatigue has been a recurring factor in global air safety investigations.

Although pilots are the most visible group affected by the fatigue rules, the occupational risk goes far beyond the aviation industry. People who work in hospitals, railway operations, and trucking, police personnel, BPO operators, and journalists all often work during those hours when human alertness naturally drops. Physical labour in these hours has been associated with metabolic syndrome, higher risk of depression, cardiovascular disease, menstrual irregularities, and immune suppression. Yet managing operational risks due to fatigue in these sectors remains uneven and under-regulated.

Thus the DGCA’s rules are laudable for situating human physiology at the centre of aviation policy.

Dr. C. Aravinda is an academic and public health physician. The views expressed here are personal.