The pilot of a helicopter that crashed in the New South Wales Hunter region, killing all three onboard, had his licence suspended in 2013 for a series of flying offences.

Key points: Helicopter pilot had licence suspended for 6 months for dangerous flying

Helicopter pilot had licence suspended for 6 months for dangerous flying Friend and fellow helicopter owner Dick Smith surprised by finding

Friend and fellow helicopter owner Dick Smith surprised by finding Smith says Mr Green failed to take common safety precautions

Sydney conservationist Richard Green, his wife Carolyn and passenger John Davis were found in the helicopter's wreckage in mountainous terrain, south of Cessnock, in the Watagans National Park on Monday.

The aircraft, which took off from Breeza in northern NSW on Saturday, had been reported missing on Monday after it failed to arrive at its destination, Mona Vale.

Mr and Mrs Green, both licensed pilots, were the owners of the helicopter and used it to fly to some of Australia's most remote locations to photograph the landscape.

While investigations are still underway as to what may have caused the accident, documents have shed light on Mr Green's flying history.

They reveal that he had his private licence suspended for six months in July 2013 after what was described as a "pattern of non-compliance over some years".

According to the Civil Aviation Safety Authority (CASA), Mr Green was involved in six incidents of dangerous flying between 2007 and 2012.

During three of those incidents, CASA said there had been a risk of a collision with other aircraft.

In one incident, Mr Green flew directly over another helicopter at a distance of about nine metres or less, which forced the second pilot to take evasive measures.

In another incident, Mr Green was reported to have performed an "unnecessary manoeuvre" creating risk of collision and injury to two other aircraft and their passengers.

Later in November 2012, Mr Green was also found to have breached civil aviation rules after he flew his aircraft immediately after an accident during which it had sustained significant damage.

The aircraft had been damaged after Mr Green struck overhead power lines while flying about 105 metres from his point of take-off.

"The damage was significant, and the aircraft was unsafe for further flight, however; despite this [Mr Green] then proceeded to fly the aircraft approximately 250 metres," court documents stated.

Civil aviation rules stipulate that pilots must not fly an aircraft if there is a defect or damage that may endanger the safety of the aircraft, or any people or property.

Mr Green had also been reported to have conducted unauthorised repairs on his aircraft after a separate incident, and to have undertaken unauthorised flights with those repairs.

Mr Green had argued for a stay on the suspension, claiming that CASA's allegations were false and made with malice, however the request was refused.

Richard Green's EC-135 helicopter. ( Courtesy Richard Green Photography )

Dick Smith surprised by suspension

Entrepreneur Dick Smith was friends with Mr Davis for over 50 years.

Mr Smith said he knew Mr Green and his wife because they were fellow helicopter owners, but had little contact with them in recent years.

He said he was surprised to hear of Mr Green's suspension.

"I understood Richard was very experienced and a very good helicopter pilot," he said.

"I'm quite horrified about what I've been reading in the newspapers who've been calling him a rogue pilot and that he's had his licence suspended.

"I didn't know anything about that and most helicopter pilots didn't know about that and I think it will be really interesting to see what comes out publicly."

Mr Smith said it was concerning that Mr Green was flying after the incidents that earned him the six-month suspension.

"I'd like to get the full evidence, but to find that a pilot was suspended for six months — that's a long time," he said.

"I'd like to get a full explanation because I'm sure John Davis didn't know that — I certainly had no idea.

"It could be that the regulator is not doing its job because in some of the things I've read, it really worries me that Richard was flying."