Aviation safety investigations & reports

Cessna 172K, VH-RGT, 3 km ESE Mittagong NSW, 11 January 1985

Investigation number:
Status: Completed
Investigation completed


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The pilot reported that the aircraft became airborne after a ground roll of about 700 metres and initial climb was commenced at an indicated airspeed of 65 knots. Soon after lift off a lack of climb performance became noticeable and the airspeed reduced to 50 knots. Several gradual turns were made to avoid trees but the aircraft struck trees on rising terrain and impacted the ground. Examination of the engine revealed that the two front cylinders had been running over-rich. An incorrect model carburettor was found to have been fitted to the engine. However, it could not be determined if this had been the cause of the of the fuel mixture problem. Local aero club pilots reported that, in this aircraft, with the mixture control in the full rich position, the engine obtained about 200 RPM less than the optimum. It was well known to club pilots that the mixture control required leaning out by about three centimetres before take-off to achieve the correct engine performance. On the day of the accident, the pilot leaned the mixture slightly less than one centrimetre. It is likely that the loss of aircraft performance was the result of reduced engine performance caused by an over-rich mixture.

Download Final Report
[Download  PDF: 22KB]
General details
Date: 11 January 1985   Investigation status: Completed  
Time: 1132 (approx)    
Location: 3 km ESE Mittagong    
State: New South Wales    
Release date: 05 November 1985   Occurrence category: Accident  
Report status: Final   Highest injury level: Minor  

Aircraft details

Aircraft details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 172  
Aircraft registration VH-RGT  
Type of operation Private  
Damage to aircraft Destroyed  
Departure point Mittagong NSW  
Departure time 1132 (approx)  
Destination Coffs Harbour NSW