Feb 11, 2018, 06:12 IST
Sources : timesofindia.indiatimes.com
MUMBAI: The Directorate General of Civil Aviation(DGCA) has grounded two Vistara pilots after a flight they were steering descended to an altitude where an Air Indiaaircraft was flying towards them.
A mid-air collision was averted by a few seconds, and this near-miss, also called as airprox, could be the closest shave in Indian skies in the recent years. The incident took place in Mumbai airspace after 8pm on Wednesday when AI’s Airbus A-319 (VT-SCA)— Mumbai to Bhopal (AI 631)—was at 27,000 feet.
Vistara’s A-320 Neo (VT-TNE)—Delhi to Pune (UK 997)—with 152 passengers had been assigned a flight level of 29,000 feet, said a source. But UK 997 came down to 27,100 feet and the two planes were flying towards each other with a vertical separation of just 100 feet.
But a Vistara source claimed that the air traffic control (ATC) had asked their pilots to be at 27,000 feet and that they did not do so inadvertently. At that moment, the traffic collision avoidance system (TCAS) alarms went off in cockpits of both the planes and a mid-air collision was averted. “AI 631 and UK 997 at one point were 100 feet apart vertically and 2.8km laterally apart. This is the most serious near miss in the recent times and it happened in the Mumbai terminal manoeuvring area (TMA),” said a source.
TMA is a designated area of controlled airspace surrounding a major airport with high volume of traffic. 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 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 said this was a ‘serious’ near-miss and the Aircraft Accident Investigation Bureau is probing it. Modern aircraft have TCAS that issue two advisories to pilots: traffic advisories (TAs) and resolution advisories (RAs). In the first step, a TA is issued to give an advance warning to crew of two planes that they are headed in the same direction. In the second stage, RA is issued which asks crew to take evasive action to avoid mid-air collisions. In this case, RA was issued.