Aviation safety investigations & reports

Grumman-Frakes G73T Turbo Mallard, VH-JAW, Lowendal Island WA, 25 August 1988

Investigation number:
Status: Completed
Investigation completed


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During the take off run, on the open sea and just prior to lift off, the right engine suffered a total failure. The pilot was unable to maintain directional control, due to the prevailing conditions, and the aircraft finally stopped on a sandbar. The left hand float, float pylon and outboard three metres of the left wing were torn off during the deceleration. A strip examination of the failed engine revealed that there had been a failure of the compressor turbine section following a sulphidation attack which initiated a fatigue failure of the compressor blades. The compressor turbine was inspected 279 hours prior to the failure and sulphidation was detected at that time, however, the damage was recorded as being within acceptable limits. The engine manufacturers recommend that the engine be washed daily and that 200 hourly borescope inspections be carried out for signs of sulphidation on the blades. The operator washed the engine daily, however, a borescope inspection was not carried out during the period between the compressor turbine inspection and the engine failure. A borescope inspection 79 hours prior to the engine failure would probably have disclosed the advanced state of blade corrosion.

Download Final Report
[Download  PDF: 23KB]
General details
Date: 25 August 1988   Investigation status: Completed  
Time: 1515    
Location: Lowendal Island    
State: Western Australia    
Release date: 17 March 1989   Occurrence category: Accident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Grumman American Aviation Corp  
Aircraft model G-73  
Aircraft registration VH-JAW  
Serial number J26  
Type of operation Charter  
Damage to aircraft Substantial  
Departure point Lowendal Island WA  
Departure time 1515  
Destination Karratha WA