Aviation safety investigations & reports

Flight control systems involving a Pilatus Britten-Norman Ltd BN-2A-8, VH-FCO, Near Horn Island, Aerodrome, QLD on 23 November 1998

Investigation number:
199805247
Status: Completed
Investigation completed

Summary

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The pilot reported that the aircraft appeared to be slow to respond to aileron control inputs during the previous flight. While carrying out a flight control check prior to departure for the next flight, he noticed that the right aileron did not respond to cockpit control column inputs. The pilot cancelled the flight and advised company maintenance personnel of the apparent problem. Examination revealed that the control rod for the right aileron had fractured, separating the aileron from the aileron control system. Specialist examination of the control rod confirmed that the fracture originated in the internally threaded tube end fitting at the point where the fitting was pinned to the centre tube section of the rod. The features of the fracture were consistent with the application of excessive stress. There was no evidence of pre-existing cracking or other defects. The spherical bearing in the rod end fitting had seized and there was evidence of sliding contact between the outer edge of the inner race of this bearing and the aileron attachment fitting. This suggested that the rod probably failed as a result of aileron control input loads applied after the rod end bearing had seized. It could not be determined when the control rod had been fitted to the aircraft. A scheduled 100 hourly maintenance inspection of the aircraft had been completed on the day prior to the incident and no abnormality concerning the aileron control system was noted. The maintenance organisation considered that during routine maintenance activities it was difficult to inspect the complete aileron assembly in the area where the failure occurred. Following advice concerning this incident, the Civil Aviation Safety Authority commenced a review of the maintenance organisation's inspection and certification procedures.
Download Final Report
[Download  PDF: 13KB]
 
 
 
General details
Date: 23 November 1998   Investigation status: Completed  
Time: 10:00 EST    
State: Queensland   Occurrence type: Flight control systems  
Release date: 27 January 1999   Occurrence category: Incident  
Report status: Final    

Aircraft details

Aircraft details
Aircraft manufacturer Pilatus Britten-Norman Ltd  
Aircraft model BN-2A-8  
Aircraft registration VH-FCO  
Sector Piston  
Damage to aircraft Nil  
Departure point Dauan Island Qld  
Destination Horn Island Qld