Julian Dean Kramer (52), also known as Julianne, or ''JK'', was the Wakatipu Aero Club's chief flying instructor and mentor to many aviators in New Zealand and overseas.
The pilot of 30 years experience in aeroplanes flew solo a privately owned Robinson R22 helicopter, registration ZK-HCG, between Wanaka and Queenstown aerodromes, via the Cardrona Valley, Wanaka, on November 8, 2012.
About 8.35pm, a witness on the ground saw the helicopter approach and then looked away.
Hearing an ''unusual'' noise the witness looked back and saw the machine was descending at a high rate with the main rotor stationary.
He watched it descend and strike the ground, although fire did not ignite.
Emergency services were immediately notified and the first responders to the accident site found the pilot dead of multiple traumatic injuries. The aircraft was destroyed, including its emergency locater beacon.
Most of the wreckage was found 5m downhill from the impact point.
Parts of the passenger door were located about 200m from the site indicating ''significant damage'' happened at altitude before ground impact, safety investigator Colin Grounsell reported.
''As a result of a loss of main rotor control, the main rotor blades diverged from the normal plane of rotation initially striking the tail boom, Once this had occurred, recovery of the situation by the pilot was impossible.
''The helicopter had been severely disrupted due to the severity of the impact, the pilot had been thrown clear and was found 2m to the front left-hand side of the helicopter.''
There were no signs of any pre-existing medical condition which could have affected the pilot and no alcohol or drugs present in the pilot's blood.
A Robinson Helicopter Company technical investigator viewed the wreckage and found no evidence which would indicate the helicopter was not in a serviceable condition before the accident.
There were no defects found which may have prevented the engine from providing full power.
However, during the safety investigation, the helicopter was found to be 25 hours overdue for its 50-hour scheduled inspection, which mainly focuses on engine maintenance.
''The helicopter was technically not airworthy, which placed both the pilot and the owner in non-compliance with the CARs'' (Civil Aviation rules),'' Mr Grounsell reported.
A large bird's nest was found to be completely covering the engine's left-hand cylinders.
However, there was no evidence the nest had a detrimental effect on engine operation and the cowling made it ''extremely difficult'' for any pilot to visually inspect the engine before flight.
The authority's Safety Promotion Unit was made aware of the difficulties in conducting an effective bird nest check on the Robinson R22 helicopter engine.
A Vector magazine article will be published highlighting the difficulty to pilots and how to avoid the hazards of low-G flight in the Robinson R22.
Low-G flight is a condition when the helicopter becomes temporarily weightless, and can be catastrophic.
In some instances, it causes the rotor to flap beyond its limits and cause structural damage to the aircraft.
