Nearly 330 passengers had a narrow escape after two IndiGo planes averted a mid-air collision over the Bangalore airspace on Tuesday, prompting authorities to launch a probe into the incident, industry sources said. The aircraft involved in the incident were operating on Coimbatore-Hyderabad and Bangalore-Cochin routes. Spokespersons of IndiGo as well as the Bangalore International Airport Limited (BIAL) confirmed the incident. The Hyderabad-bound plane had 162 passengers while the other aircraft was carrying 166 passengers. Sources told PTI that the vertical separation between the two aircraft was only about 200 feet and a mid-air collision was averted after the Traffic Collision Avoidance System (TCAS) alarms went off. Sources said Aircraft Accident Investigation Board (AAIB) has started an investigation into the incident that happened on July 10. "The TCAS-Resolution Advisory system was triggered on two of our aircraft operating Coimbatore-Hyderabad and Bangalore-Cochin routes, respectively, on July 10, 2018. "Following normal procedure this has been reported to the regulator," the airline spokesperson said in a statement. In a statement issued in Bengaluru, the BIAL spokesperson said an incident involving two A320 aircraft operated by Indigo Airlines occurred in South Indian airspace on July 10 some distance away from Kempegowda International Airport, Bengaluru. "The aircraft were routing Coimbatore-Hyderabad and Bangalore-Cochin respectively at an altitude in excess of 27,000 ft. Pilots on board both aircraft were alerted to the presence of the other by on-board systems and, subsequently reported the occurrence to the DGCA in accordance with standard operating procedures," the spokesperson added. The Directorate General of Civil Aviation (DGCA) is the aviation regulator.