It came when John took a job in Pahiatua driving a loader truck for a topdressing company, the traditional starting position for aspiring topdressing pilots.
He completed his agricultural pilot training in Taihape and two years later started flying helicopters in Dannevirke. It was challenging work, and there were few rules.
"In Dannevirke I was doing mainly agricultural work," says John. "But there was the odd aircraft accident or farmer hurt at the back of farms where [the helicopter] would be called in. It was primitive, it was like [TV show] M.A.S.H, you were in a stretcher strapped to the outside of the helicopter and we only took them the minimum distance such as to a road end.
"We got great satisfaction out of helping people and it was obvious early on that we could make a difference to the patient's outcome and often saved a life."
The Taupo years
John and wife Trish shifted to Taupo in 1978 where he was offered a job working for Helicopters New Zealand with a bigger machine. One of the first jobs he worked on was building the Turoa Skifield.
By then venison recovery, with its terrible accident rate, was also underway. John estimates he attended a crash every week.
Helicopters New Zealand had the only chopper in the central North Island capable of putting a stretcher inside, so it began being called to jobs by the Rescue Co-ordination Centre in Wellington. John had no medical training and says he had to do the best he could.
"I remember one [crash] we went to in the Kaingaroa Forest. There were three guys. I was there with one other guy and I had to use the Funnell triage system. The one that was lying on the ground unconscious we got him onto a stretcher, got him in and the other two. We had seating for five and there were six of us. On the way in, one of the guys in the back crashed over on top of me. I'm trying to fly along and this guy's lying all over me. I pushed on his head, and his whole scalp peeled back."
Back then, people outside the cities who needed urgent hospital care were usually transferred by ambulance. For someone in Taumarunui, that could mean a wait of hours.
Many arrived too late to be saved. But John says mainstream emergency services didn't appreciate the benefits helicopters offered.
"It was difficult convincing people that the helicopter could make a difference."
Things began to change after a call to a crash on the Desert Road. John and paramedic Pat Wynne flew a critically injured patient with severe chest injuries direct to Waikato Hospital. With no helipad, John landed in a park. The next morning he had a call from the doctor in charge of the hospital's Intensive Care Unit. John assumed the worst.
"I imagined that we had killed this patient. We got there and Dr Hyde said he had just returned from Australia where he had been working as an ICU specialist and they had just started using helicopters there to transfer patients."
That was the start. Dr Hyde set up a retrieval team to transfer patients to Waikato from outlying areas. Others also saw the potential to save lives. One of them was Peter "Eph" Smith, commander of the Taupo Fire Service, who made sure staff going on helicopter rescues were properly equipped, and Laurie Burdett, then charge nurse at Taupo Hospital, who offered to send along nurses to medical jobs.
John says finally the powers that be decided helicopters weren't going away and he began transporting paramedics from Taupo St John Ambulance and later Barry Shepherd from Taupo Police with him to rescues. The helicopter company took all the risk - and would later invoice ACC for the work.
In 1984 John and Trish bought Helicopters New Zealand's Taupo base and a Squirrel helicopter and renamed it Helicopter Services BOP. John worked on lifting, spraying, firefighting and power line construction jobs but he was also available for rescues.
Cellphones didn't exist and he didn't have a pager. If he went into town, he would always tell Trish where he would be, although sometimes she had to resort to driving around to find him. Eph Smith eventually supplied John with a Fire Service pager, which made "a world of difference".
Shortly after Helicopter Services BOP started, a plane carrying Philips New Zealand staff from Turangi to Wellington went missing and John was asked to act as ground co-ordinator for the Rescue Co-ordination Centre. Up to 25 aircraft searched for two weeks, without success. The plane was located later, a long way off course. All three on board were dead.
As a result Philips New Zealand decided to thank the people of the central North Island, by forming the Philips Search and Rescue Trust. John was one of the original trustees. The trust still exists, and runs rescue helicopter services in the Central North Island, including Taupo's Greenlea and Rotorua's Baytrust rescue helicopters.
The trust bought medical equipment for the helicopter and had an operational budget of $30,000 a year. The money meant that if a rescue was needed and the police or ACC refused to pay, at least the direct operating costs were covered.
Pushing the boundaries
1992 brought the ground-breaking mercy dash from Invercargill to remote Campbell Island to rescue a shark attack victim. Nobody knew whether the flight was even possible.
If the chopper had mechanical trouble or ran out of fuel during the 1400km journey, it would have ditched into icy seas, where rescue was unlikely.
Fortuitously, John had been to Campbell Island in the past, on a resupply ship visiting the MetService base, and had left drums of fuel there in case of a rescue, never thinking it would be needed.
It was a Friday in April and he had been working all day when he had a call from a MetService contact saying employee Mike Fraser had been attacked by a shark. Could John rescue him?
"I said 'of course' and then I hung up the phone and said 'how am I going to do that?' The next call was to a friend of mine, Grant Biel who had done a lot of resupply flights. He thought it was possible if we doubled the range, so I rang up the engineers and said 'don't go home, we have to build a fuel system and check it's 100 per cent reliable'.
"We had three 44-gallon [200 litre] drums and we ran a hose from a portable fuel pump to the back of the cabin and they plumbed it into the fuel tank." The Squirrel was airborne by 8pm the same night, testing the fuel system on the flight to Invercargill.
Pat Wynne and Grant Biel flew down in Grant's plane with medical supplies. Grant, who accompanied John on most of his long-range offshore missions, was second pilot on the chopper flight and with no seats in the back, Pat had to crouch among the drums.
"He's trying to cram in all these medical supplies and I'm saying 'Pat, we're too heavy, we're overloaded as it is.' We were that heavy we had to fly the helicopter across the tarmac to get it airborne."
The island was a tiny target and GPS in those days was intermittent. When the aeroplane accompanying the Squirrel turned back due to lack of fuel range, John and Grant had to use "dead reckoning" for the last part of the journey. The research vessel Tangaroa had steamed to Campbell Island and the helicopter pilots were able to use the ship's radar to guide them down. It was 6am and pitch dark.
"We loaded Mike in and flew him across the base, refuelled and took off. The aeroplane left from Invercargill and met us about halfway and accompanied us back. Pat, Grant and I all came back in the aeroplane to Taupo and I got home about 8pm that night."
John earned a New Zealand Bravery Medal for the feat. But, he says, it was a group effort and Grant's experience with long distance flights was key.
Other high-profile missions included the rescue of six DOC workers from an erupting Raoul Island in 2006, disaster relief in Banda Aceh, Indonesia, ferrying food and water to outlying villages after the 2004 Boxing Day tsunami, and most recently, dropping supplies to kayaker Scott Donaldson, who was attempting to paddle from Australia to New Zealand but ran out of food just short of the Taranaki coast.
A team effort
Not every person on every rescue was able to be saved. Some patients died before the chopper arrived, or afterwards. John remembers one incident in Te Puke where he and the team tried to get to an injured man. The weather was so bad it was impossible to fly.
When they finally made it, he had died.
He says rescues involving children motivated him the most.
"They're the ones I still have some difficulty with. Kids either as a result of violence or as a result of accidents. Being able to help them, that's pretty important."
And he says every rescue was a team effort.
"It's easy to write a story about John Funnell and think 'he's saved all these people', but without people like Barry Shepherd, Pat Wynne, Spencer Wallace, among many others, I couldn't have done that. They're sitting in the back, probably petrified to death. I try and make collective decisions but if you get it wrong you might not come home. It's a huge commitment.
"Then there's all the support people that backed me. Trish, office staff, engineers who work tirelessly on the aircraft and keep them in top order. There's a huge team of people behind you every time you launch. Barry [Shepherd] has worked tirelessly for years and has had no recognition, and it's me that's collected all the bloody medals and awards, and that's why I don't comment much about them because it's a bit embarrassing, to be honest."
It sounds a lucky life, but it almost wasn't. In 2001 John was diagnosed with a brain tumour. He and Trish searched the world for a specialist surgeon and eventually had the tumour removed in Germany, by world-renowned neurological surgeon Madjid Samii, who drilled a hole in John's head, a delicate operation that took over eight hours. Just 24 hours later, John was up and walking around, and six months later, was flying again. But he had considered what might happen if his brain had been damaged during the tumour removal.
"I made Trish promise that if it didn't go okay, that she would take me to Holland [for voluntary euthanasia]. I think she agreed after days of me persisting."
As well as his aviation businesses Helicopter Services and Taupo Tandem Skydiving, John has tourism interests, a small farm and his own plane to get around in. Sons Hamish and Mark have taken over the day-to-day running of the aviation interests and John and partner Chrissy are setting up their own beekeeping operation.
John says he'll still turn out if called on because helping others is not something you just walk away from.
With the help of writer John McCrystal, he's writing his autobiography, which should be published in late 2016. It promises to be a great read.