The Civil Aviation Department has been proactively following up on an incident in which the Flight Data Processors (FDPs) of System I experienced a momentary glitch two days ago.

The department said at 4.20pm on August 13, the Air Traffic Management System issued an alert stating the FDPs were not functioning properly.

Co-ordinating with air traffic control supervisors on-site, technical staff switched from System I to System II according to established procedures at 4.26pm.

Air Traffic Control Officers then continued to provide services as usual. Once System I was rebooted, the operation of System I returned to normal and then served as a backup as per design.

As a precaution, officers temporarily halted giving clearance for departing flights for about six minutes but arrivals and flights flying through the Hong Kong Flight Information Region were not affected.

The department said System I and II are independent but identical systems with the same design and functionality. They can immediately take up each other’s role in the event of an outage to maintain continuity of services.

During the incident, it was not necessary to activate the Ultimate Fallback System in the process, it added.

The department has asked the contractor to conduct a thorough investigation and provide a solution as soon as possible.