What happened
During a series of agricultural spraying missions involving superphosphate, an aircraft was performing its thirty-sixth flight of the day. Earlier in the day, the pilot and property owner had conducted an aerial survey to mark power poles located in a valley near the airstrip. While initial conditions featured a light north-easterly wind and 16° Celsius, environmental conditions shifted significantly by the time the final mission commenced, with temperatures rising to 28° Celsius and winds shifting to a south-westerly direction.
During an earlier flight that same day, the aircraft was seen losing altitude after passing over high-voltage lines. On the subsequent flight, the pilot was observed executing a sharp left turn through the valley near a marked pole. During the final mission, while attempting to follow a similar flight path, the aircraft's left wing tip and landing gear collided with powerlines situated southwest of a previously marked pole. The impact caused a broken line to become lodged behind the left aileron washout plate. Consequently, the aircraft crashed into the ground approximately 100 metres past the powerpole. The force of the impact was so severe that it destroyed the airframe and rendered the cockpit area non-survivable, resulting in fatalities.
Findings
Investigations into the wreckage found no evidence of mechanical failure or pre-existing defects in the aircraft components. Instead, the investigation determined that the aircraft was operating in excess of its maximum allowable takeoff weight. This weight discrepancy occurred because the loader driver's truck bucket load gauge lacked a proper calibration or conversion chart.
It is believed the pilot attempted to fly through the valley to utilize the downslope to compensate for degraded climb performance caused by the increased temperature and heavy load. Furthermore, the absence of a superphosphate trail at the time of impact suggests the pilot may have been unaware of the powerlines' location or failed to maintain adequate clearance while maneuvering.