Air Traffic Control pre-empted a collision by sending the Jet flight on a “go-around” instead of landing, and allowing the Indigo flight to take off to Bangalore.

The Directorate General of Civil Aviation is investigating the “runway incursion” by Indigo flight 6E415, an Airbus A 320 with 178 passengers. Jet flight 9W 616, a Boeing 737, was carrying 103 passengers from Kolkata.

Indigo blamed the failure of the lights; the flight was eventually guided by a jeep.

“The DGCA is conducting an inquiry; we will send them our reports,” said ATC general manager M G Jhungare.

“The pilot overshot taxiway N1, essentially because the taxiway lights were not working,” said Aditya Ghosh, president, Indigo. “We alerted ATC and they sent us a follow-me jeep, which guided the aircraft to the main runway, after which we were able to depart. However, in that time, there may have been other planes waiting to land on the runway. The ATC would have asked them to make a go-around.”

Mumbai International Airport Limited (MIAL) officials said they had informed the ATC about the non-functioning of a portion of lights on N1 on Wednesday. They stressed other planes had been able to depart without a hitch using the “follow-me” service, essentially a jeep that acts as a guiding light.

“Whether the ATC offered the follow-me service to the Indigo pilot or whether the pilot refused the service will be known after the DGCA completes its inquiry,” said an MIAL spokesperson. “Two aircraft before and two after the Indigo departure were able to take off with the follow-me service.”