SINGAPORE - Once an alert was received of a suspected "hijacking" of a civil airliner heading towards Singapore, two F-16 fighter jets were scrambled within minutes.
On the plane, the hijackers were subdued by passengers while the fighters closed in on the aircraft, intercepted it and escorted it to land for follow-up action by the police.
This scenario played out on Thursday (March 14) as part of the multi-agency Exercise Vigilant Shield, which took place at Changi Air Base.
With air traffic in Changi expected to grow in the coming years, the air defence exercise was important to ensure the processes involved in dealing with air threats remained relevant, said the exercise's chief planner, Lieutenant-Colonel Zanna Lee from the Republic of Singapore Air Force (RSAF).
"When we carry out our operations, we must make sure that the safety of the other civil airliners is also taken into consideration. And we will try as much as possible not to affect the Changi traffic," said the air warfare officer from the Air Defence Task Force.
When Changi Airport Terminal 5 is completed by 2030, it will have an initial capacity of up to 50 million passengers a year. This is more than twice the size of any of the other three main terminals.
Senior Minister of State for Defence Heng Chee How, who observed Thursday's exercise, said Singapore remains a terrorist target, citing the hijacking of Singapore Airlines Flight 117 in 1991 and the Sept 11, 2001, attacks in the US as examples of the dangers faced.
"These are the things that worry us but at the same time, it causes us to want to be ever vigilant... and to coordinate amongst the different forces.''
These included not only those within the Singapore Armed Forces and the RSAF but also related agencies such as the Singapore Police Force (SPF) and the Civil Aviation Authority of Singapore (CAAS), he said, with the aim "to make sure that our reflexes are honed, and we are able to respond resolutely, swiftly, decisively".
An RSAFKC-135 aerial tanker took on the role of a commercial plane for the exercise, which also involved the CAAS and the police.
Superintendent Chong Chung Meng, who headed the SPF's response in Thursday's exercise, said its role was to ensure the safe release of the hostages.
"Nothing beats having a real exercise to ensure that the agencies are able to coordinate, because on the ground there may be some differences in understanding, so this exercise was critical in helping our officers practise these processes," said the head of operations at the Airport Police Division.
Coordinated by the Air Defence Task Force, which was formed in 2010, Thursday's exercise was meant to demonstrate the capabilities of the RSAF and how it works with other government agencies to counter potential air threats.
The previous two editions of the exercise were held in 2014 and 2016.
The exercise comes after a potential bomb threat incident on board a Scoot plane on April 5 last year, which led to two F-15SG fighter jets being activated.
They escorted Flight TR634 back to Changi Airport. The Scoot plane, which carried 173 passengers and six crew members, was bound for Hat Yai in Thailand.
Captain Spencer Lee, the air defence coordinator in the Scoot incident but who was not involved in Thursday's exercise, said such exercises were important to identify and address potential gaps.
He said the Scoot situation was tense at first, when they did not know there was a potential bomb threat until the fighters were scrambled.
He added: "But our training kicked in and gave us the confidence to do things in a very procedural way, so that the necessary actions could be done as quickly as possible."