Aviation safety investigations & reports

Cessna 152, VH-WLA, Mt Dunneed VIC, 14 September 1989

Investigation number:
Status: Completed
Investigation completed


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The student pilot was receiving instruction in the procedures associated with an engine failure after take off. At 1000 feet above ground level carburettor heat was applied, the throttle retarded to idle and the aircraft configured for descent. At 800 feet the power was reapplied, carburettor heat was selected off and the aircraft climbed back to repeat the lesson. After the second exercise the engine would only develop 1500 rpm and was running roughly. The instructor took over, exercised the carburettor heat and left it on, but there was no improvement in engine performance. He then carried out a forced landing in a paddock. During the latter part of the landing run the nosewheel dug into the soft surface, and the right wing was damaged. The weather conditions at the time (ambient air temperature 16-17 with a dew point of 11 and overcast) were favourable to the formation of carburettor ice. The engine had recently been overhauled. The operator reported that the aircraft normally gave only a very small drop in rpm when carburettor heat was applied. The spark plugs were found to be heavily sooted with a fresh carbon deposit, which indicated that the engine had suffered a rich cut. This is consistent with the effects of ice accumulating in the carburettor. The carburettor heat box was found to be loosely fitted to the carburettor and one side of the box had a rubber seal missing. This resulted in a loss of effectiveness of the carburettor heating system.

Download Final Report
[Download  PDF: 23KB]
General details
Date: 14 September 1989   Investigation status: Completed  
Time: 1715    
Location: Mt Dunneed    
State: Victoria    
Release date: 18 January 1990   Occurrence category: Accident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 152  
Aircraft registration VH-WLA  
Serial number 15282749  
Type of operation Flying Training  
Damage to aircraft Substantial  
Departure point Geelong VIC  
Departure time 1630  
Destination Geelong VIC