When the blips went off screens

When the blips went off screensPublished Date: 5/16/2007 - (NIE)ENSChennai, May 15: For close to five hours the blips that denote flights over Chennai sky vanished from the Air Traffic Control screens at the Chennai airport on Tuesday. This sent them scurrying for pens and chart papers as they dusted up their knowledge of guiding flights manually without seeing them on the screens. With intense concentration, sharp analytical skills and spilt second decisions, the ATC personnel ensured safe landing and take off of more than a dozen flights at the airport, between 4 p.m. and 9 p.m. Stress soared as the ATCs strained to listen to the flight position inputs radioed by the pilots of incoming and overflying flights. As they could not see the position of the flights they were supposed to guide on the screens, the ATC had to delay flights because lack of modern air traffic management mechanism affected maximum accommodation of flights on the air space. As it was peak hour, the airspace was crowded and the personnel had to work carefully and allocate safer distance for each flying aircraft as they entered Chennai airspace. Once a safe flying distance was allotted after calculating the position of other aircraft, the flights were brought in for landing. Once they closed in on the airport, the ATC on the control tower took over and brought them for a safe landing. This way they had to be in constant touch with pilots of all aircraft. When air traffic controllers dropped in for work on Tuesday evening they knew that they would have to make do with the secondary antenna because the main radar was supposed to be shut down for maintenance. But they never dreamt of the ordeal that was in store for them. Sources said that the entire system of sophisticated flight handling was thrown out of gear when the secondary radar malfunctioned. ‘‘The ATC personnel did the manual charting extremely well though it caused delays because manual flight control would mean more space between aircraft on air. Radar inputs coupled with sophisticated machines enabled accommodation of more flights in less airspace. But without these modern gadgets, the ATC personnel relied solely on their concentration skills, said a senior ATC official. He also said, ‘‘Such a scene has never occurred before though it is routine to operate using secondary radar when the main radar is under maintenance. The personnel always keep the manual charts ready as a standby to meet exigencies like this.’’ Though the situation was trying on the ATC, this was never a crisis because flights could be landed using manual traffic control.