NEW DELHI: T his was as close as it gets. On February 7, a Vistara flight descended to an altitude where an Air India aircraft was flying in the opposite direction, and the two planes then sped towards each other before a midair collision was averted by a few seconds. The near-miss is being seen as the closest shave witnessed in Indian skies in years.
The Diectorate General of Civil Aviation (DGCA) has grounded two Vistara pilots. However, Vistara sources said the air traffic control (ATC) had asked the pilots to be at 27,000 feet and they did not do so inadvertently. This incident happened in the Mumbai airspace after 8pm on Wednesday when AI’s Airbus A-319 was flying from Mumbai to Bhopal as AI 631 and was at a level of 27,000 feet.
Vistara’s A-320 Neo was flying from Delhi to Pune as UK 997 with 152 passengers and, sources said, had been assigned a flight level of 29,000 feet.
However, UK 997 came down to 27,100 feet – after which the two planes were flyin g towards each other with a vertical separation of just 100 feet. At that moment, the traffic collision avoidance system (TCAS) alarms went off in the cockpits of both the planes, and the pilots managed to avoid a midair collisio n. “At one point, AI 631 and UK 997 were 100 feet apart vertically and 2.8km laterally apart. They were just seconds away from each other. This is the most serious airport (accident) or near-miss in recent times,” said a source.
A Vistara spokesperson said: “The safety of our customers and staff is of paramount importance to us and at Vistara we diligently follow all the safety regulations and guidelines. In this particular incident, the resolution advisory (RA) got triggered due to conflicting traffic. Our pilot followed the SOP (standard operating procedure) to avoid it and carried out an uneventful landing. The matter is under investigation by relevant authorities.”
AI did not comment till the time of going to press. A senior DGCA official admitted this was a “serious” near-miss and that the Aircraft Accident Investigation Bureau (AAIB) was probing it.
A senior AI official said: “This was indeed a very close call. Our crew was acting just as it should have. There must have been some serious confusion between air traffic control and Vistara pilots that led to this.”
Modern aircraft have TCAS equipment that issue two types of advisories to pilots: traffic advisories (TAs) and resolution advisories (RAs). In the first step, a TA is issued to give an advance warning to the crew of two planes headed in the same direction. In the second stage, an RA is issued, which asks crew to take evasive action to avoid midair collisions.
This is at least the second ‘airprox’ situation in Maharashtra skies in a fortnight. On January 28, aircraft of IndiGo and Emirates breached the minimum distance over Nagpur when the IndiGo A-320 was flying from Hyderabad to Raipur and the Emirates Boeing 777 was on its way from Singapore to Dubai.