Mumbai: Aviation regulator DGCA is probing an incident of an IndiGo plane landing and an Air India aircraft taking off from the same runway in less than a minute at the Mumbai airport, officials said on Sunday.

The watchdog has derostered the Air Traffic Controller (ATC) who was on duty at the time of the incident on Saturday, while IndiGo has initiated a probe into the matter, they added. A purported video of one plane landing and another taking off from the same runway has been shared on social media.

"We are conducting a probe and have already de-rostered the ATCO involved in the incident," the DGCA official said. Mumbai airport is a single-runway operation with two crossing runways.

On a single runway RW27 at the Mumbai airport, there are around 46 arrivals and departures per hour. IndiGo said its aircraft continued the approach and landing as per the ATC instructions.

"On June 8, IndiGo flight 6E 6053 from Indore was given landing clearance by ATC at Mumbai Airport. The Pilot in Command continued the approach and landing and followed ATC instructions," IndiGo said in a statement. At IndiGo, passenger safety is paramount to us, and we have reported the incident as per procedure.

According to an Airports Authority of India (AAI) source, as a rule, departing aircraft have to cross the end of the runway or take a turn, only after which the ATC can issue the landing clearance for arriving aircraft.

"However, in this case, this was allegedly not followed," the source said.

"Mumbai airport is one of the high-density airports, which means that the number of flight movements is high. On a single runway RW27 at the airport, there are around 46 arrivals and departures per hour," said another source.

Also, Air Traffic Controllers (ATCs) are allowed to clear up to two arrivals and two departures within three minutes as per standard operating procedures, subject to certain conditions, according to source, who added that the separation minima between two aircraft can be reduced if the visibility is good.

"In this particular case that happened on Saturday at the Mumbai airport, the visibility was good and there was no air prox situation with respect to the landing IndiGo flight and the taking off Air India flight," said the source.

"There might have been a delay in quite fair visibility. The tower controller is allowed to reduce separation minima between two aircraft's if reasonable assurance has been established by visualising both aircraft's.

In the video it can be seen that departure has crossed V2 speed -- the speed at which the aircraft may safely climb with one engine inoperative and nosed up and on the other end of runway arrival is touching down," he explained.

ATCs are under "significant pressure" when there is high density traffic at airports with the safety of aircraft and passengers, the source said, adding that the DGCA probe will be looking at whether all norms were followed by the ATC as well as the pilots concerned.