New Delhi, Jan 19 (PTI) Two IndiGo planes averted mid-air collision over the Bengaluru airport just after their take-off on the morning of January 9, senior officials of aviation regulator DGCA said on Wednesday.The incident was not logged in any logbook and it was not reported by the Airports Authority of India (AAI) either, they said.Meanwhile, DGCA chief Arun Kumar told PTI that the regulator is investigating the incident "and shall take strictest action against those found delinquent".IndiGo and the AAI did not respond to PTI"s request for a statement on this matter.Officials of Directorate General of Civil Aviation (DGCA) said that the two IndiGo planes -- 6E455 (Bengaluru to Kolkata) and 6E246 (Bengaluru to Bhubaneswar) -- were involved in "breach of separation" at Bengaluru airport.Breach of separation happens when two aircraft cross the minimum mandatory vertical or horizontal distance in an airspace.Both these aircraft departed from the Bengaluru airport within a span of approximately 5 minutes on the morning of January 9, the officials mentioned."Both aircraft after departure were on converging heading i.e. moving towards each other. Approach radar controller gave diverging heading and avoided mid-air collision," one of the officials noted. PTI DSP ZMN