The pilot reported that while the aircraft was in cruising flight it suddenly began to vibrate heavily. The pilot closed the throttle but the violent vibration continued. The surrounding terrain was generally unsuitable for a forced landing, and in the latter stages of an approach towards a small paddock the right wing struck a tree. The aircraft then dived into the ground and was destroyed. It was subsequently determined that more than half of one of the two propeller blades had separated in flight. The propeller had failed as a result of fatigue cracking. A similar crack was discovered in the other blade. The propeller had only operated for 42 hours total time before the failure occurred. During the approach to land, the pilot's vision was affected by the violent vibration caused by the propeller imbalance. As a result, he was unable to accurately judge his flight path between two trees on the edge of the selected paddock.
