That came from staying in close contact with them and carefully respecting protocols such as no alcohol on the mountain and landing in certain places, he said.
"We not only do the tourism thing, we help them with other initiatives ... such as cutting down wilding pine trees."
Mr Marinkovich said the contract meant a lot to the Rotorua team and the company, as the scenic flights to Mt Tarawera were a big drawcard.
It worked closely with inbound travel agents and attended trade shows such as TRENZ to market the flights, he said.
"Through the summer it [Mt Tarawera] is one of the most popular flights," he said.
"We can do up to six trips in one day - but that's a big day."
It's a 45-minute round trip to Mt Tarawera or it can be combined with White Island for a three and a half hour trip.
Mr Marinkovich said Mt Tarawera's history and beauty made it appealing to both domestic and international tourists.
"It's the largest volcanic eruption in living memory," he said. "The Pink and White Terraces were the start of tourism in Rotorua. People used to come from all over the world."
He said Kiwis tended to choose one or the other due to cost while overseas tourists, often Australian or European, were more likely to combine White Island and Mt Tarawera.
The business is dependent on weather but Mr Marinkovich said that was monitored closely and all efforts were made to accommodate tourists' itineraries.
The feedback has been overwhelmingly positive and even passengers that started out nervous were relaxed by the return trip, he said.
Despite having flown to Mt Tarawera hundreds of times, Mr Marinkovich said he was still blown away by the views and the "scale of the mountain".
"On a nice day you can see for miles." Pilot Tarren Schneller said it was a "breathtaking view every time".
"Quite a few people scared of heights conquer their fears on the mountain."
HeliPro also recently renewed its White Island landing rights - exclusive out of Taupo and Tauranga and shared from Rotorua.
Although tourism is HeliPro Rotorua's main venture, it also does work such as lifting power lines, work with the Department of Conservation and fire fighting.
HeliPro has seven bases around the country as well as in Fiji and Australia and has operated out of Rotorua for more than 10 years.
The base at Te Puia has three pilots and three helicopters.