It had seemed like another day of routine air defence duty on Jan 22, 2008, for weapon systems officer Major (NS) Mark Lim and fighter pilot Captain Benjamin Lim.
But within minutes of receiving a call at 6.40pm, their fighter jet took to the air from Changi Air Base.
It was not a drill. Their mission was to intercept an aircraft with possibly hostile intentions that had entered Singapore's airspace.
Said Capt Lim, 37, who, at the time, had qualified for air defence duty less than six months before: "For me as a junior pilot, there were a lot of thoughts going through my mind. But adrenaline comes in, it kick-starts your engine and you go through the procedure that you have been trained for."
He and Maj (NS) Lim were flying one of two F-16D+ planes mobilised in the 1½-hour operation.
The planes were to establish communication with an Australian-registered Cessna 208 Caravan float plane which did not have an approved flight plan, check its intentions, and escort it to land at Changi Airport.
While air traffic controllers on the ground had already communicated with the aircraft, which had come from the Thai island of Koh Samui, the situation was deemed uncertain enough that the fighter jets had to be activated.
Said Mr Mark Lim, 48, who left the force in 2014 and is now a business owner: "(The Cessna pilot)... said he was having some emergency... Later, he added that he was low on fuel and needed to land immediately. So we got permission to escort him back to Changi Airport from there. But anyone can say the same thing. So we had to ensure that he was compliant."
The civilian airliner caused a 50-minute lockdown of Singapore's airspace, affecting commercial planes. Its pilot later admitted to not having airworthiness certification from Australia's civil aviation authority and was fined $5,000.
Mr Lim said: "I think this incident demonstrated our RSAF's ever-readiness to respond to such situations, and also the importance of the SAF in being vigilant 24/7 to safeguard our homeland.For us, the professionalism and all the training that we have gone through paid off."
Lim Min Zhang