Accident Details
A pilot reported that the flight departed from an agricultural strip situated in a valley surrounded by hills. The aircraft was fully loaded with superphosphate intended for spreading on a property approximately one mile from the strip. The pilot had previously surveyed the property and selected a flight route that ascended through a valley between hills and then over a low ridge to the destination.
After takeoff, the pilot set climb power and selected climb flap to follow the predetermined route. As the aircraft approached the low ridge, the pilot perceived that the aircraft was descending rather than climbing. To clear a clump of trees, the pilot executed a partial dump of the load and applied additional flap. The airspeed dropped from an initial climb speed of 70 knots to 60 knots, and the pilot did not increase power. Approximately 300 metres later, another partial dump was performed to clear another tree. After clearing that tree, the pilot initiated another partial dump and turned right in an attempt to escape a rapidly deteriorating situation. Immediately upon initiating the turn, the right wing dropped and the aircraft stalled, impacting the ground on the right wing. The aircraft cartwheeled to a stop about 50 metres from the initial impact point.
Investigation Findings
The company chief pilot examined the accident site and noted that the flight path through the valley presented a classic false horizon situation. The surrounding hills caused the pilot to perceive the flight path as over flat terrain, whereas the terrain was actually rising at approximately 5 degrees up to the ridge. The chief pilot further advised that at high gross weight with only cruise power set, the aircraft would not have been able to outclimb the terrain.
Probable Cause
The official investigation determined that examination of the wreckage did not disclose any pre-impact factors that may have contributed to the accident. Weather and pilot workload were not considered factors. The pilot had flown approximately 1,200 hours on agricultural operations and 244 hours on the aircraft type. His loss of situational awareness could be due in part to his relatively low experience. The following factors were considered relevant to the development of the accident:
- At high weight, and with climb power applied, the pilot flew the aircraft on an inappropriate flight path into rising terrain.
- The pilot did not take appropriate remedial actions when the aircraft could not outclimb the terrain and the aircraft speed deteriorated.
- The pilot lost control of the aircraft while attempting a turn at low speed.