MUMBAI: The operational meltdown by IndiGo, India?s largest airline, in the first week of December has brought back to the fore the need for experienced specialists running the country's aviation regulator and not let it stay the revolving door for government bureaucrats at its helm.

Experts have raised concerns that ten generalist officials have served at the top office at the Directorate General of Civil Aviation (DGCA) in the last 17 years?all serving or retired bureaucrats, lacking specialist knowledge critical in running a sector like aviation, from the government's elite Indian Administrative Service, or IAS, cadre.

The last non-IAS officer to head the DGCA was Kanu Gohain, a technocrat who rose through the ranks of the aviation regulator to the top job before retiring in 2008. Since then, all 10 director generals have been bureaucrats, including the incumbent, Faiz Ahmed Kidwai, who took over in January.

In early December, IndiGo canceled more than 4,500 flights due to a pilot shortage, failing to meet new DGCA regulations capping pilots' flying hours from midnight to 6AM. A nationwide uproar prompted the aviation ministry and DGCA to launch an investigation, slash IndiGo's daily flights by 10%, and demand explanations from IndiGo chief executive officer (CEO) Pieter Elbers and the airline's chief operating officer Isidre Porqueras.

?They did not spot the craters in time, they did not prune the expanded schedules in time nor they did not verify if they had the pilots for the schedule, even when they saw the troubles brewing in November,? said Sanjay Lazar, aviation safety specialist and CEO of Avialaz Consulting.

Six months ago, Air India's Flight 171 crashed seconds after takeoff from Ahmedabad, with at least 260 fatalities. The Aircraft Accident Investigation Bureau is still investigating what caused the country?s worst civil aviation disaster.