Calcutta airport’s rickety radar system that scans the skies from Jamshedpur to Rajshahi in Bangladesh was on the blink for more than eight hours on Tuesday, delaying about 50 flights.
“The route surveillance and approach radar did not function till noon causing delay in take-off and landing. This happened because of a technical snag,” an airport official said. “The radar has been causing problems since Monday afternoon and it shut down early on Tuesday,” he added.
The airport’s radar system, installed in 1998, often develops snags. Sources said it should be replaced immediately because it has outlived its life.
Airport officials said flights from the city were delayed by 20-30 minutes from early morning to until the system was up by noon. Incoming flights had to hover at least half an hour on an average as air traffic control deployed its manual mode for landing that requires meticulous calculation of the co-ordinates of all airport-bound aircraft and constant communication with each pilot.
“Voice communication (with the ATC) becomes all-important when the radar fails. It is a tedious and stressful process,” said Captain Sarvesh Gupta, a senior pilot with Jet Airways.
The route surveillance radar can catch any flying object within a radius of up to 250 nautical miles or 463km from Calcutta. The data is transmitted in the form of a “bleep” on a screen, allowing air traffic personnel to correctly read the position, height and distance of an aircraft flying out of or coming to the city.
It keeps vigil of aircraft movement till Jamshedpur in the west, Bhubaneswar in the east and Rajshahi in the north. A radar at Berhampur, Odisha, shares responsibility for the southern section but it too is out of order because of the battering it got from cyclone Phailin.
The approach radar gives the co-ordinates of an aircraft within 60 nautical miles or 111.2km, helping the ATC guide the incoming planes to land on one of the two runways of the airport.
The ATC also had to maintain a higher lateral separation between two aircraft in the absence of electronic surveillance. “Under the normal circumstances, the separation is 10 nautical miles or 18.5km. Today it was eight times more…80 nautical miles or 148.1km,” the official said.
Airports Authority of India officials said Rs 271 crore was in the pipeline to modernise the Calcutta ATC, including new equipment worth about Rs 150 crore.