Aviation safety investigations & reports

Robinson R22HP, VH-ONE, 37 km WNW of Mt House Station WA, 19 May 1985

Investigation number:
Status: Completed
Investigation completed


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After the helicopter had been transitioned to forward flight, the pilot felt a vibration through both the collective and cyclic controls. During his attempts to stop the vibration, the helicopter was allowed to descend. As he then selected a climb attitude the helicopter yawed to the right. The pilot was unable to correct the yaw and the tail struck a tree which slowed the yawing and allowed the pilot to land the helicopter. Initial inspection revealed that the intermediate flexplate in the tail rotor drive system had disintegrated. A metallurgical examination of the flexplate indicated that it probably failed due to overload. The examination also revealed that prior to the application of the overload that resulted in the ultimate failure, the flexplate had been cracked and weakened by another previous overload. The cause of the overload that resulted in the pre-existing crack could not be determined. However, examination of the tail rotor indicated that the ultimate failure most likely occurred as a result of a minor tail rotor strike whilst the helicopter was transitioning into forward flight.

Download Final Report
[Download  PDF: 22KB]
General details
Date: 19 May 1985   Investigation status: Completed  
Time: 1000    
Location: 37 km WNW of Mt House Station    
State: Western Australia    
Release date: 30 December 1985   Occurrence category: Accident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Robinson Helicopter Co  
Aircraft model R22  
Aircraft registration VH-ONE  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Substantial  
Departure point 33 km WNW of Mt House Station WA  
Departure time 1000  
Destination 33 km WNW of Mt House Station WA