On 13 September 2013, the flight instructor and student pilot of a Robinson R22 helicopter, registered VH-ONT, were preparing for a dual training flight from Armidale, New South Wales.
Prior to take-off, the instructor explained the purpose of the fuel mixture control guard, the use of the carburettor heat, and took the student through the start-up checklist.
At about 1515 Eastern Standard Time, the helicopter departed, with the instructor operating the controls. During the climb, at about 300 ft above ground level (AGL), the instructor handed control of the helicopter over to the student. When maintaining 1,200 ft AGL, the instructor discussed with the student on how to enter a descent. After confirming that they would reduce the engine power, the instructor asked the student to pull the carburettor heat on.
The instructor looked outside to check for traffic and the engine then stopped. The instructor immediately initiated an autorotation and lowered the collective. He observed that the fuel mixture control was in the idle cut-off position. The student had removed the fuel mixture control guard, inadvertently pulled the fuel mixture control instead of the carburettor heat control and then replaced the guard. The instructor asked the student to push the fuel mixture control back in and he broadcast a ‘MAYDAY’ call.
The instructor selected a paddock and focused on the autorotation. Prior to the landing flare, the low rotor revolutions per minute (RRPM) horn sounded. The helicopter landed and ran on the ground on its skids, before rolling onto its side due to the slope of the paddock. Both occupants sustained minor injuries and the helicopter was substantially damaged.
This accident highlights the benefit of pilots positively identifying the control to be manipulated, prior to performing the action.