Aviation safety investigations & reports

Cessna R182, VH-ITS, Somersby NSW, 21 December 1985

Investigation number:
Status: Completed
Investigation completed


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While cruising at 3000 feet, the aircraft suddenly encountered strong turbulence. Almost immediately afterwards, the engine commenced to run roughly and the pilot was unable to maintain height. He intended to carry out a precautionary landing on a freeway, but then sighted a strip nearby and positioned the aircraft for a left circuit. He subsequently advised that he elected not to lower the landing gear because he considered that the aircraft would have rolled beyond the end of the 550 metres long sealed strip. The aircraft touched down some 350 metres beyond the threshold and slid for 134 metres before coming to rest. Investigation disclosed that the exhaust valve guide clearances in five cylinders were less than the minimum specified by the engine manufacturer. The engine power loss resulted when an exhaust valve in one cylinder became jammed in the valve guide by a build-up of carbon deposits. The loss of power occurred over unfavourable terrain, and the pilot had been committed to a downwind approach to the strip selected for the forced landing.

Download Final Report
[Download  PDF: 22KB]
General details
Date: 21 December 1985   Investigation status: Completed  
Time: 1205 approx    
Location: Somersby    
State: New South Wales    
Release date: 19 August 1986   Occurrence category: Accident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 182  
Aircraft registration VH-ITS  
Type of operation Private  
Damage to aircraft Substantial  
Departure point Mittagong NSW  
Departure time 1205 approx  
Destination Port Macquarie NSW