First hearing about the opportunity from colleagues, the keen runner was now putting the word out, even enlisting her husband, Reuben Harrison.
"She thinks she will beat me, but she won't," he said.
When asked if the couple trained together, Mr Harrison said: "Sometimes, but it gets a bit too competitive".
Laura Hyde, marketing and fundraising manager for the trust said they were looking for more people to join crew and staff as they took on this "epic challenge".
"There are four distances to choose from, a full marathon, a half-marathon, and a 10km route, as well as a kids' race, so there really is something for everyone."
She said the trust completed more than 300 life-saving missions each year in the region and needed to raise more than $1.2 million per year to keep its services free of charge and available 24/7 to everyone in Hawke's Bay.
Mrs Harrison said she and her husband were aiming to raise about $200, "but obviously we would love to be able to get more than that because a single one-hour flight can cost more than $11,000".
She said she had recently been recovering from a knee injury suffered during the last half-marathon, but was slowly clocking up the kilometres again.
Ms Hyde said people would fundraise through sponsorship and every dollar would go directly to the services of the Rescue Helicopter.
"Everyone who takes part in one of the races on behalf of the Rescue Helicopter will receive a full fundraising pack, event t-shirt, and certificate of achievement."
"We'd like as many people as possible to join our team for this amazing challenge! If running isn't your "thing", you can also join our cheering party on the day to cheer on our runners"
Mr and Mrs Harrison's givealittle page can be accessed here: givealittle.co.nz/fundraiser/jessandreubenharrison/