A mystery plane on a collision course with a KLM flight over the Bay of Bengal threw the city airport authorities into a tizzy on Sunday morning.
The aircraft, which has still not been identified, was not following a flight path. It stayed in the area under the Calcutta Air Traffic Control (ATC)’s surveillance for three hours. But the pilot did not establish contact with the city ATC, said officials.
The plane came within three nautical miles of a KLM Royal Dutch flight from Amsterdam to Kuala Lumpur near Bhubaneswar, which is around 200 nautical miles from Calcutta.
According to air safety norms, two aircraft should be separated by at least 10 nautical miles if they are under radar surveillance.
When there is no radar surveillance, the stipulated distance between two aircraft is 80 nautical miles or more.
“We froze as the KLM pilot told us that he could see an aircraft but could not identify its type,” said an ATC official.
The mystery plane’s altitude could not be gauged, as the pilot had switched off a transponder.
The aircraft abruptly changed direction and flew away from the KLM flight.
Half an hour after the KLM aircraft, an Indian airline flight from Singapore to Delhi took the same route.
A Jet Airways Singapore-Delhi flight, a Malaysian Airlines London-Kuala Lumpur flight and two Qantas flights from Frankfurt and London to Singapore followed at short intervals.
“All the flights were alerted about the mystery plane’s presence,” said the official. None of the pilots, however, saw it.
A number of regular air routes were closed on Sunday to facilitate the test fire of the BrahMos cruise missile in Orissa. The flights that take the routes followed diverted paths.
The Indian Air Force (IAF) tried to track the mystery plane on its radar at Kalaikunda and Chennai. “The officers did not tell us whether they were successful,” stated another airport official.
“The ATC is informed about the movement of our aircraft well in advance. Moreover, an IAF pilot would definitely respond to the ATC’s calls,” said wing commander R.K. Das, defence spokesperson in Calcutta.
The mystery aircraft first appeared on the Calcutta ATC’s radar around 10 am. It was moving south.
The KLM plane was flying to Kuala Lumpur from the opposite direction.
“Despite several requests to the pilot to give the call sign, there was no response. It was strange that the aircraft flew for three hours in our area but the pilot did not communicate with us,” observed a senior airport official.
Around 1 pm, the aircraft disappeared from the radar as mysteriously as it had appeared.