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"Exceptional flying" by a Fiordland pilot saved a $540,000 helicopter from destruction today as he nursed the crippled machine for almost half an hour before making a safe emergency landing.

Southern Lakes Helicopters pilot Richard Hayes was on a venison recovery operation in Fiordland National Park when his Robinson R44 helicopter lost its tail rotor about 7.15am.

Mr Hayes, who is more used to showing tourists the grandeur of one of New Zealand's remotest areas, flew for some 25 minutes - including a section across Lake Te Anau - before landing the chopper like a fixed wing aircraft into an agricultural airstrip in the Ramparts area.

Southern Lakes Helicopters operations manager Lloyd Matheson said after the "complete disintegration" of the tail rotor at an altitude of about 4500ft, Mr Hayes' only option was to maintain forward momentum to steer the aircraft and keep it stable.

That meant him landing at a speed of 80 knots, risking his main rotors hitting the ground and possibly destroying the aircraft as it skidded some 45 metres along the ground.

Mr Hayes, the only occupant of the four-seater R44, walked away unscathed.

"It was an exceptional piece of flying," Mr Matheson told NZPA.

"It's what they practice for," he said of the pilot, who also flies rescue missions in the Fiordland area.

"The structure stood up to that mid-air disintegration and he's coped with it very well."

Mr Matheson said the "status" of the chopper - insured for just under $540,000 - "dictated the end result".

He said it appeared something had come out of the helicopter - which was flying with its doors open - and gone through the tail rotor.

"It was total disintegration of the tail rotor system."

Mr Matheson said while Mr Hayes was nursing the stricken aircraft, staff at the company's Te Anau base were assessing options for landing the helicopter safely.

"We were trying to look for some flat land, but of course there's no flat land or paddocks in Fiordland National Park."

Mr Hayes was told to fly to Waiau airstrip where emergency services were heading to prepare for a crash landing, "but he didn't quite make it there", instead coming in over open country to the agricultural airstrip, about 10km east of Te Anau Aerodrome.
Mr Matheson said fire and ambulance crews ended up at a maintenance base "quite some distance away from where he landed".

The almost new aircraft was repairable, he said.

The Civil Aviation Authority is investigating.