Unclear computer screens at the UK鈥檚 largest air traffic control centre caused some controllers to misjudge the altitude and destination of airplanes and recommend that others be sent into the wrong airspace sectors, leaked documents have revealed.
Shortly after the 拢623 million centre in Swanwick, Hampshire, was opened in January 2002, some traffic controllers reported difficulties reading newly installed screens. The centre鈥檚 operator, National Air Traffic Services (NATS), and the Civil Aviation Authority said the problem was 鈥渆rgonomic鈥� and posed no threat to aircraft safety.
But documents obtained by the UK magazine Computer Weekly now show that air traffic controllers sometimes misjudged the altitude of aircraft by thousands of metres, completely misread destinations and recommended that airplanes be sent into the wrong airspace sectors.
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These 鈥渟afety observation reports鈥� are filed by the controllers themselves to their supervisors. One notes that a controller misread an airplane鈥檚 altitude as 36,000 feet (11,000 metres), when it was actually 30,000 feet (9150m). This controller had difficulty reading 鈥渨ithout having nose on screen,鈥� the report says. Another controller wrongly read an airplane鈥檚 destination code as Cardiff rather than Glasgow.
The documents reportedly show that some controllers categorised the incidents as safety-related. Managers and supervisors said 鈥測es鈥� when asked whether they agreed that the mistakes raised a 鈥渟afety-related鈥� issue.
Safety margin
However, the errors did not lead to any near misses and NATS stands by its original assessment that this is not a safety issue. It disputes the significance of the reports stating: 鈥淣ATS completely rejects suggestions that feedback reports from air traffic controllers expose safety concerns.鈥�
A NATS spokesman says misjudgments were only made by controllers involved with planning an airplane鈥檚 route and not by those in charge of guiding the aircraft in flight, who have a different kind of display.
This means a safe distance was maintained between airplanes at all times, the spokesman says. He adds that most controllers quickly corrected their own mistakes.
鈥淭his didn鈥檛 result in any safety implications or any safety reports as such,鈥� he told 快猫短视频. 鈥淎ll they鈥檝e said is they were slightly confused at the beginning, when they first looked, but when they looked closely it was okay.鈥�
Bigger fonts
At the new centre, 28 inch (71 cm) computer monitors have taken the place of traditional round radar screens. NATS says it is in the process of improving the readability of planning controllers鈥� displays by increasing the fonts used. This was recommended in a Health and Safety Executive report produced in March 2002.
The UK鈥檚 air traffic controllers鈥� union Prospect says in a statement: 鈥淭he work of an air traffic controller is highly pressurised and it is right and proper that controllers report any factors which could make their work more difficult.鈥�
The Swanwick centre has taken six years to develop and is run by NATS, which was privatised in July 2001. There have been numerous other computer-related problems at Swanwick and its support center at West Drayton, near Heathrow.