During descent the aircraft suffered a loss of power. The pilot was forced to land into an unsuitable area resulting in the aircraft being damaged when it ran into a fence. The weather was conducive to the formation of carburettor ice at the time of the accident. The carburettor heat flapper valve was found to be stuck in the open (cold air) position. This valve normally closes when the throttle is retarded giving "automatic" protection against ice build up.
The flapper valve shaft had suffered from a lack of lubrication.
The following factors were considered relevant to the development of the accident.
1. The weather was conducive to the formation of carburettor ice.
2. The carburettor heat valve was inoperative.
3. The engine suffered from a loss of power over an area unsuitable for a forced landing.
|Date:||22 May 1993||Investigation status:||Completed|
|Release date:||09 July 1993||Occurrence category:||Accident|
|Aircraft manufacturer||de Havilland Aircraft Pty Ltd|
|Damage to aircraft||Substantial|