At about 400 feet above ground level, on climb out after takeoff, the engine suddenly lost power. The pilot was faced with landing on unsuitable terrain and as a result the aircraft was substantially damaged. The cause of the power loss was determined to have been spark plug carbon fouling due to an excessively rich fuel mixture. During previous maintenance by the aircraft owner, the mixture slide needle had been refitted incorrectly to the piston slide assembly. This positioned the needle about three millimetres higher than it should have been, resulting in the mixture being over-rich throughout the throttle range. This occurrence was not the subject of an on-site investigation.
