Accident Overview
An aerial topdressing flight ended in a fatal crash near Otangiwai when the aircraft struck a power conductor. The pilot, who had accumulated 10,898 flying hours, was conducting sowing operations from an airstrip on a farm. The aircraft, registration ZK-DUI, was found wrecked on a level river flat at approximately 11:00, after failing to return from a sortie that began at 10:20. Fire did not occur.
Flight Sequence
The pilot initially sowed over higher ground, but as the morning progressed, turbulence became significant in the lee of the hills. He then turned his attention to the lower part of the farm, completing a sortie over the northeastern corner of the property. After taking off for another series of sowing runs over the same area, the aircraft did not return.
Wreckage Details
The aircraft had dived into the ground at an angle of at least 60 degrees from horizontal, probably near vertical. The propeller separated from the engine and was buried 1 meter in the soil. Compression damage severed the fuselage at the middle of the cockpit. The remainder of the aircraft rebounded and came to rest on its main wheels approximately 8 meters from the forward fuselage. The rear fuselage was folded in half behind the wing. No fertilizer was in the hopper or near the wreck. The left outer wing panel was found about 100 meters away, with its leading edge section missing. Cable marks indicated the leading edge had been sheared off from the main spar by a wire cable.
Investigation Findings
Investigation revealed that the aircraft had collided in flight with a single 11,000-volt conductor at roughly the midpoint of a 500-meter span between two poles. The collision occurred at about 220 feet above ground level and approximately 600 meters from the crash site. The power line was part of a 4-kilometer-long electrical supply line installed by the local power authority approximately five weeks prior.
Probable Cause
The accident investigator concluded that this accident was probably caused by a loss of control of the aircraft after it was substantially damaged in a collision with a power conductor.