Jet fell off radar for longer than usual, top Hong Kong aviation official admits

Hong Kong’s new air traffic control system plunged into deeper controversy yesterday when the city’s aviation chief admitted that it was “not ideal” and “relatively long” for a flight to drop off radar for 12 seconds, as one did last week. In admitting the disappearance was longer than similar problems under the old system, DG of civil aviation Simon Li Tin-chui said the latest incident suggested no safety risk. Li said that the ICAO requires air traffic systems to refresh and show aircraft locations on the radar screen at least once every five seconds. Hong Kong’s Civil Aviation Department (CAD) has set the new HK$1.56b Auto Trac III system to refresh flight locations every four seconds. But last Tuesday, a day after the new system was fully launched, a flight disappeared from the screen for 12 seconds. “The operation of the new system has been very smooth since November 14,” Li said. “We now handle more than 1,800 flights a day and no flight has been delayed because of the new system. It’s a complex electronic system. Even though our colleagues have tried their very best, in the initial stage, it is possible that we could run into special situations. The CAD has a set of procedures to guide the controllers to ensure aviation safety.” He said all controllers had sufficient training. Raymond Li, assistant director general of civil aviation, said the plane had been near Sunny Bay, Lantau, when it disappeared.<br/>But he said controllers could still see the plane with their own eyes because it was nearby. He said there were various possible reasons for a flight to drop from the screen, including hills blocking signals. The department had yet to identify the cause of the 12-second disappearance, but had sent information to manufacturer Raytheon to find it. The CAD is keeping the old system for six months, in case the new one has more problems. <br/>