Hundreds of Indian airline pilots plan to form an association to challenge flying duty regulations they say cause fatigue and jeopardise safety after an IndiGo pilot collapsed and died before his flight.
Former pilots have taken to social media and newspaper columns to publicly raise concerns that airlines, though operating within regulatory frameworks, are stretching them to the brink as air travel booms in India.
The sudden death last week of an IndiGo pilot heightened those worries although India's biggest airline says he had a 27-hour break before duty and was in good health.
Captain Shakti Lumba, a retired vice president at IndiGo, has garnered the support of hundreds of pilots who plan to come together with an existing group of 600 to raise awareness and lodge concerns over fatigue with authorities and airlines.
"The main focus of the group will be compliance with international standards and recommended practices, flight safety and pilot fatigue - which is a clear and present danger to (the) safety of aircraft operations in India," said Lumba, who was involved in setting up IndiGo's operations from 2005.
India's aviation watchdog did not respond to a Reuters request for comment.
In the United States, regulators allow flights manned by two pilots to serve maximum duty time of 14 hours during the day and 9-10 hours for late-night flights. India does not differentiate on the basis of day or night-time and allows pilots to be on duty for 13 hours within a 24-hour span.
While airline pilot fatigue is a global problem, India is uniquely at the heart of the matter as the world's fastest-growing aviation market, where hundreds of new planes are on order by IndiGo and Tata group-owned Air India.
About a dozen Indian pilots with whom Reuters spoke in recent weeks shared worries not just about work hours but flight schedules they say are erratic and worsened sometimes by consecutive late-night departures without sufficient rest.
A Reuters review of a chat group with over 400 pilots showed growing stress after the IndiGo pilot's death. One pilot wrote "consecutive midnights are a killer", while another said "it's time to start fixing things that are ailing Indian aviation".
India's Vistara airline told Reuters that management of fatigue - which it says it has kept at among the lowest levels in the industry - remains a high "focus area". Vistara said duty timings for pilots are planned well within the norms to accommodate any unforeseen disruptions.
IndiGo, which operates 1,900 flights a day, said it has a comprehensive fatigue management system which tracks various parameters in line with international best practices.
Aviation Minister Jyotiraditya Scindia told Reuters in March that the government wants India, the world's most populous country, to become a global aviation hub and foresees "an explosion of air traffic".