A mid-air disaster was averted in the nick of time as two IndiGo aircraft came dangerously close to a collision over Bengaluru airspace on Tuesday. As many as 328 passengers were on board the two flights, vertically separated by a mere 200 feet.
Alert pilots took immediate evasive manoeuvres to avert a tragedy. An IndiGo Coimbatore to Hyderabad Airbus A-320 flight (6E-779) was cruising at 27,300 ft when it came in the way of another IndiGo flight (6E-6505) heading to Kochi from Bengaluru.
It was a near escape. When the onboard collision avoidance systems started beeping, the two aircraft were just about eight km away from each other.
The vertical separation was too narrow for comfort, as the flight speed exceeded several hundred kilometres per hour. The air traffic control (ATC) ordered the 6E-779 to climb up to 36,000 ft and the 6E-6505 to 28,000 ft.
IndiGo, in an official statement, said the TCAS-Resolution Advisory system was triggered on the two aircraft. “Following normal procedure, this has been reported to the regulator,” the airline said. TCAS (Traffic Collision Avoidance System) is designed as a defence against mid-air collisions.
The system monitors the airspace around an aircraft for other aircraft equipped with a corresponding active transponder, independent of the ATC. It then warns pilots of the presence of other transponder-equipped aircraft which may present a collision threat.
Once TCAS generates a Resolution Advisory, an automated voice alerts the pilot and instructs him/her on what to do next with utmost urgency. If an incoming flight is to pass just below, the voice command says “climb, climb” and “descend, descend”, if the aircraft’s path is just above. TCAS systems are mandated for all civilian aircraft operating in India.
Officials in the Directorate General of Civil Aviation (DGCA) said they were aware of the incident and have ordered an inquiry.
The airline has reported the matter to the DGCA as in keeping with existing regulations. The Aircraft Accident Investigation Board (AAIB) has already started an investigation into the incident.
In a similar development on February 7, a Vistara aircraft had come close to an Air India flight in the Mumbai airspace. AAIB had launched an investigation into this. Carrying 152 passengers, the Pune-bound flight was just 100 feet away from the Air India flight bound for Bhopal, that carried 109 passengers.
Another near miss was reported between an IndiGo flight from Kolkata to Agartala and an Air Deccan flight from Agartala to Kolkata. The two aircraft were flying over Bangladesh.