SINGAPORE - When the opening chords of the national anthem are struck at this year's National Day Parade, audiences can expect to see the state flag soar past the National Stadium before making its way across the skyline of the city's southern coast, from the domes of Gardens by the Bay to the three towers of Marina Bay Sands.

This is the first time that the state flag flypast will be taking this route - and those who are watching the parade at home will also be able to see the breathtaking vistas during the flypast, which will be captured on screen.

Preparations for the flypast involved a team of about 300 active and operationally ready national servicemen in the lead-up to the NDP. Even the task of rolling up the flag - which measure 27m by 18m, is a mammoth one that takes 25 people about two hours to complete.

While only one flag will be seen during the actual flypast, back-ups are prepared in case of damage, with rolled flags delivered to Pulau Sudong, Paya Lebar Air Base and Sembawang Air Base.

The task of rigging the flag to the helicopter is also a tricky one. Ballasts, cable slings and a release rope are first attached to the flag. The flag weighs a whopping 1,247kg after it has been rigged, with close co-ordination required to ensure that the rolled flag unfurls fully and remains in good condition when the CH-47D Chinook helicopter carrying the flag leaves for the flypast from the air base.

Lieutenant Colonel Liao Ming Hao, the 35-year-old pilot of the Chinook helicopter, said that one of the key challenges is the level of precision that is required.

"Having to arrive there within seconds of the stipulated time means that throughout the route, I need my flight crew to constantly advise me whether I'm early or late."

This is made even more difficult by the fact that the pilot is unable to see the flag, and thus reliant on instructions from the aircrew specialist about when to fly faster or maintain the speed.

"If the speed increases or reduces, the flag tends to fold at certain portions," said Second Warrant Officer (2WO) Vijaikumar, 42.

As the aircrew specialist, he also looks through a hatch in the aircraft to monitor the flag and make sure that it has been properly attached to the helicopter.

"Before the flag is actually picked up... my heart beats very fast because at the end of the day, it is still our national flag," he told reporters at a media event last week (July 9), outlining how pains are taken to prevent damage to the flag at every stage of the process.

"When we pick it up and the flag unfurls, the sense of pride and honour... is very hard to explain in words."