Around 60,000 people are expected to line the route, from Stormont to the city centre, and a bumper collection will help keep this vital service in the air during 2022 and beyond.
The Helicopter Emergency Medical Service (HEMS) provided by the Air Ambulance was introduced five years ago and had its first call out on July 22, 2017.
With no funding other than public donations, it costs £2 million every year (£5,500 every day) to keep the HEMS operational.
Parade organisers the Grand Orange Lodge of Ireland are urging everyone taking part in the centennial celebration, and those watching along the four-and-a-half mile route, to “give generously to this very worthy cause”.
Air Ambulance NI fundraising manager Grace Williams has thanked the Grand Lodge for what she described as a “wonderful opportunity”.
She said: “We are delighted to be the nominated charity for the Grand Orange Lodge of Ireland’s centenary event and look forward to the event on Saturday.
“As a service we rely heavily on charitable donations to keep the medical team in the air, delivering critical care to patients who have suffered trauma throughout Northern Ireland – without continued support, the team simply couldn’t fly.
“The Helicopter Emergency Medical Service responds on average to two incidents daily, somewhere in Northern Ireland. Since the service first launched in July 2017, the HEMS has been tasked on over 2,916 occasions.”
Ms Williamson added: “The charity Air Ambulance NI, in partnership with the Northern Ireland Ambulance Service, provides the HEMS for Northern Ireland.
“The HEMS team attend patients who are seriously ill or injured, bringing emergency pre hospital care direct to the casualty, with the aim of saving lives, brains and limbs.
“With a daily fundraising need of £5,500, we are so grateful to the Grand Orange Lodge of Ireland for this wonderful opportunity!”
The parade on Saturday, involving around 25,000 members of the various loyal orders, will be one of largest ever staged in Northern Ireland.
More than 130 bands have confirmed their attendance at the event which was due to take place last year but postponed due to the Covid pandemic.
It will move off at 1pm following platform speeches, a service of thanksgiving and an Act of Remembrance from 12 noon.
From Belfast City Hall, local lodges will begin parading back to their districts at 6pm.
• Air Ambulance NI would welcome additional help on the day from volunteer collectors. If you think you can assist, please contact Grace on 07718483326.