The Civil Aviation Department has revealed that the Air Traffic Control Centre experienced a power supply failure on Thursday night.
The department deferred giving clearance to departing flights at the Hong Kong International Airport for around ten minutes as a precaution. It announced the hitch in a response to media enquiries at midnight.
The department said in a statement that around 8:45pm on Thursday, two controllers’ workstations experienced the failure when a “power supply selector” they shared encountered a momentary hitch.
“During the occurrence, all other workstations in the Air Traffic Control Centre were not affected,” it said.
The department said despite delaying departure flights for ten minutes, arrivals and flights through the Hong Kong Flight Information Region – which are handled simultaneously by the new Air Traffic Management System – were not affected.
The new air traffic control system, known as AT3, came into full use in November last year and cost HK$1.5 billion. The contract was awarded to the US-based Raytheon Company.
On April 8, the system lost track of flight information for eight planes, forcing the fallback system to be used for the first time.
A report submitted by the contractor on April 15 said the problem was caused by users’ preferences settings exceeding the preset system limit. Controllers can make personalised preferences on the system such as font size, screen brightness, and size of the control sector, among others.
Raytheon said it was committed to providing a software fix for testing within two weeks to fully resolve the problem in the long run. It said the software fix will alert users when it rejects the creation of new preferences settings once the amount reaches the preset limit, without affecting the normal operation of the new system. It will also increase the preset limit.
Previously, the system encountered dozens of malfunctions such as displaying non-existent planes, disappearing flight data, false instances of overlapping flights, and false collision alerts.