A REPORT into an aircraft accident that killed a Queenstowner warns pilots must stay within aircraft operating limits.
Transport Accident Investigation Commission today releases its report into a helicopter crash in the Southern Alps in 2011 that killed Wanaka instructor Graham Stott, 31, and his Queenstown student pilot Marcus Hoogvliet, 21.
TAIC finds that the Wanaka Helicopters Robinson R22 – returning from Haast to Wanaka on a cross country training flight – broke up in mid-air when the main rotor blades struck the tail boom.
This was caused by one or a combination of three conditions: severe or extreme turbulence buffeting the chopper; the pilots making large and abrupt movements of the controls; the main rotor speed dropping below its lower limit.
TAIC says the helicopter was operating in a “high-risk situation” because it was flying near maximum permissible weight at high altitude and entering an area of moderate to extreme turbulence.
The report, however, doesn’t blame the pilots.
After encountering higher-than-forecast wind conditions on their way to the coast, they took on more fuel at Neils Beach, near Haast, changed their flight plan, on the advice of a pilot they met there, and phoned their Wanaka base to push back their scheduled arrival time.
On their way back they spoke to another aircraft operator who said they didn’t seem concerned about the conditions.
TAIC reports neither pilot had alcohol or performance-impairing substances in their blood.
TAIC has made two recommendations to the Civil Aviation director on pilot and instructor ratings on Robinson helicopters.
It’s also made two recommendations supporting international efforts to improve the crash survivability of emergency locator transmitters and promote alternative tracking systems.
A key lesson, TAIC says, is: “Pilots must be fully aware of the operating limitations of aircraft they fly, and must always stay within those limitations.”