“I would imagine that the airport would try to compensate [the affected passengers]. It’s not the passengers fault. It’s an airport problem.”

The systems failure paralysed flight and baggage collection information and on digital platforms for more than nine hours.

The authority said problems were first noticed at 7am and an executive added that airlines were notified and the public alerted at about 9am.

A large whiteboard was put up in the restricted area of the airport to provide handwritten updates from staff, which attracted a crowd of hundreds desperate for information.

Ronald Pong, an information security management specialist and chairman of the IT governance committee of the Smart City Consortium, said the response time was unacceptable because computer systems should be monitored round the clock.

“It’s puzzling why it took the Airport Authority two hours to disclose the issue,” he added. “If there was proper monitoring in place, the situation should have been known immediately, allowing for the implementation of contingency plans and prompt public announcements of the proposed solutions.”

Announcements were made in the departure hall to notify passengers of the system failure, but some complained about difficulty reading the handwritten information that replaced the electronic displays.

Boarding passes also did not show the appropriate gate number.

Pong said the contingency plans highlighted the authority’s lack of effective incident response and crisis management preparedness.

He speculated that the problems stemmed from the authority’s backend system – its database – and that the electronic information boards were the front end.

Pong said it was clear that the problem did not start at the front end since the database information could have been shown on other monitors, the backup plan for such situations.

“If airlines are provided an application programming interface for scheduling that reconciles with the Airport Authority’s system, it could be the third-party processes that caused the problem,” Pong added.

“The authority should clarify whether the error lies with the airlines or its own system’s backend.

“Regardless, the response time to the incident was undeniably slow and caused a lot of unnecessary hurdles for passengers.”

An airport executive said at noon that glitches would not be fixed “in a short period of time” and staff started to set up temporary digital displays of flight information in the departure hall.

There were no whiteboards seen in the departures hall, but small A3-sized papers attached under the existing display screens.

A Post reporter also saw one of the whiteboards in the arrivals hall had not been updated for 20 minutes.

Francis Fong Po-kiu, the honorary president of the Hong Kong Information Technology Federation, said the airport’s contingency measures lacked a human-centric approach.

He added a backup system capable of operating independently with an existing database at least 80 per cent of the time if the main system went down was essential for an international airport.

“A solid backup system needs to be able to failover, which means switching to a redundant or standby computer server or system on the failure or abnormal termination of the previously active application,” Fong explained.

He said the authority needed to improve its backup plans or create a suitable new one because the airport’s expansion project, which includes a runway, a second terminal building and a new concourse was expected to be completed this year.

A similar incident, where staff were forced to enter flight information by hand on whiteboards, happened at London’s Gatwick and Heathrow airports in 2018.

Hundreds of passengers at Gatwick missed their flights in August when display screens failed after a Vodafone fibre optic cable was damaged.

Airport staff used whiteboards and megaphones to relay gate information to passengers.

Departure screens went blank for two days a few weeks later at Bristol after a cyberattack.

Airport management decided to take flight information screens offline to contain the problem.

Staff also used whiteboards and marker pens to keep passengers informed about flights.

Similar methods were implemented in September 2018 at Heathrow after the flight information displays went offline in the morning because of a connection problem.

Passengers were also advised to use the airport’s website and mobile app to find out which gate their flights were scheduled to leave from.