History of Flight
On 3 May 2022, at 0647Z, a pilot operating a Piper PA-25-235 (Pawnee) aircraft, registration ZS-AWX, departed from Clan Airfield in KwaZulu-Natal province for a crop-spraying mission at a private farm in Albert Falls. The flight was conducted under visual meteorological conditions (VMC) by day and in accordance with Part 137 of South Africa's Civil Aviation Regulations.
According to the pilot, after completing the fifth swath line of spraying, the aircraft was climbing to align for the sixth swath when the pilot made a left turn at approximately 100 feet above ground level. At that moment, the engine began to run rough, and the aircraft experienced abnormal vibrations. The pilot noted a loss of engine power. He then turned right towards an open field to execute a forced landing. During the turn, loud spluttering noises were heard from the engine compartment. The pilot leaned the mixture and activated the carburettor heat, but these actions did not restore power.
The pilot successfully executed a forced landing in the open field. The aircraft rolled approximately 60 metres on the ground before the propeller blades struck a perimeter fence. The aircraft flattened the fence and rolled over to the other side, ground-looped, and impacted bushes before coming to a stop. The pilot was not injured during the accident sequence. However, the aircraft sustained substantial damage.
Probable Cause
The investigation determined that the in-flight engine power loss resulted from a failure of the left magneto drive gear due to a worn-out drive gear shaft, which led to advanced engine timing and necessitated the subsequent forced landing. A contributing factor was improper maintenance.
Aircraft and Operator Information
The aircraft, a Piper PA-25-235 (Pawnee), was operated by Natal Aerial Spray (PTY) LTD. The pilot held a Commercial Pilot Licence (CPL), was 25 years old, and had accumulated 1232.9 total flying hours, including 288.0 hours on the accident aircraft type.
Meteorological Conditions
At the time of the accident, wind was calm (360° at 0 knots), temperature 14°C, dew point 14°C, visibility CAVOK, and QNH 1023 hPa.
Damage
The aircraft was substantially damaged. No other property damage was reported beyond the fence and bushes.