Two passenger flights almost came close to mid-air collision in Kolkata last Monday before the planes were pulled apart after being alerted by the onboard collision boarding system.
Both the planes were carrying around 350 people on board, reported Times of India. A probe has been ordered into the incident, while two Air Traffic Control (ATC) officials – a radar controller and another procedure controller – have been benched in immediate reaction to the incident.
A Kolkata airport official informed, as reported by the national daily, that an IndiGo flight which took off for Bagdogra was asked by the ATC to climb to 29,000 feet, while another AirAsia India flight — arriving from the same location — was also asked to descend to the same level. Following the instructions, the flights were moving towards each other, unaware that they were on a course for collision.
But as soon as both the flights reached the minimum separation level, the onboard traffic collision avoidance system (TCAS) was triggered, with only 200ft distance left between both the aircraft.
The initiation of the TCAS means the computers take control over the pilots and ask one aircraft to climb over, while also asking the other to descend ensuring that they don’t collide.
“Planes have to either have a vertical separation of 1000 ft or lateral separation of 5-10 nautical miles (9-18 km). In this instance, the lateral separation was almost non-existence. At the speed the planes fly, a 200 ft distance can disappear in a fraction of a second. It was a major breach in-flight safety,” an official was quoted as saying by the daily.
A high-level inquiry has been initiated with a radar controller and a procedure benched till the investigation is completed.
“An inquiry has been ordered into the investigation and we are cooperating fully with the DGCA and ministry of civil aviation,” said an AirAsia official spokesperson according to the report.