Two international flights got dangerously close to each other in Mumbai’s mega crowded skies on Friday afternoon. They were seconds apart from each other when the collision avoidance system kicked in and pulled them apart. An air traffic controller has been grounded. Both the flights were passing through this route due to the closure of Pakistan airspace since February 27. The Mumbai airspace has seen a sharp rise in overflying aircraft since then and the ATC has been putting in a superhuman effort + to manage this spurt in traffic.

The scare happened at 1.40 pm Friday when an Air France Boeing 777 was cruising at 32,000 feet en route from Ho Chi Minh City to Paris as AF 253. And an Etihad Airbus 320 was winging its way from Abu Dhabi to Kathmandu as EY 290 at 31,000 feet.“At 1.40 pm, Mumbai air traffic control (ATC) asked the Etihad flight to climb to 33,000 feet. During climb, this aircraft came almost face-to-face with AF 253 that was coming from the opposite direction. The two aircraft were just three nautical miles away, seconds apart, from each other,” said sources.

The “traffic collision avoidance systems” (TCAS) equipment on these two aircraft got activated, after which pilots pulled the two planes apart.

Confirming this serious near miss, a senior ATC official said: “This happened and the matter is under investigation. The air traffic controller has been off rostered (taken off duty). Traffic density was very high (in Mumbai flight information region) due to Pakistan airspace closure.”

A senior official of the Directorate General of Civil Aviation also confirmed the near miss and said a probe has been ordered.

Pakistan has repeatedly deferred reopening its airspace. The latest date for that to happen is Monday, but no one knows when that will indeed happen.

The over fortnight-long closure is now beginning to strain resources of both airlines and Mumbai ATC that is handling the entire diverted traffic.

Flights between west and south/southeast Asia are taking a longer route. For airlines that has meant adding a stop on ultralong and long nonstops, like Delhi-New York, which translates into higher crew and fuel requirement.

The implications are no longer just on finances and network. The effect, as is clear from Fridays near miss near Mumbai, is on safety too due to overworked and stressed out controllers who have been putting a superhuman effort since February 27. But stress may be showing now.

The mid-air collision was averted by the collision avoidance system which issues two types of advisories to pilots: first a traffic advisory (TA) to give an advance warning to crew of two planes that they are headed in the same direction and in second stage resolution advisory (RA) that asks crew to take evasive action to avoid mid-air collisions.