IndiGo airlines
A mid-air collision was averted after an AirAsia flight and an Indigo Airlines flight came as close as 9km while flying on the same routeAmit Dave/Reuters

It was a lucky escape for hundreds of passengers in India as two airborne flights flying on the same route managed to avert a mid-air collision, over the city of Varanasi in the northern state of Uttar Pradesh.

The two Airbus A320s – one operated by AirAsia and the other by IndiGo Airlines – were roughly 15 seconds apart when some last-minute manoeuvring prevented the crash, sources told The Times of India.

An investigation has been launched by the Aircraft Accident Investigation Board into the incident and officers are trying to ascertain whether Air Traffic Control had warned the pilots of the planes that they were closing in on each other.

The paper reported on 20 April that the incident took place sometime last week and did not give the exact date. The Air Asia flight I5 768 was en route to capital New Delhi from Bagdogra – a small town in northeast India, while the IndiGo flight 6E 398 was heading to Bagdogra from New Delhi.

Sources told the paper that on entering Varanasi airspace, the Air Traffic Control office instructed the pilot of the AirAsia flight to descend to 34,000 feet and maintain its path, but the flight allegedly continued to descend below the assigned level. The aircraft reached 33,000 feet where the IndiGo aircraft was flying and the two aircrafts came as close as nine kilometres and were 15 seconds apart from each other.

The collision was averted after the airborne collision avoidance systems on the aircraft alerted the pilots to veer away from each other.

AirAsia India said that the airline "is currently investigating the matter with relevant regulatory authorities".

"We will refrain from disclosing further information until we have established the facts," a spokesperson noted. The commander of the flight has reportedly been grounded pending the probe.