Snow Commander 600 S2D, VH-SCY, Nandowrie, 100 km south-west of Emerald, Queensland, on 21 June 1990

Circumstances:

The pilot had been spreading Graslan, a herbicide, about five kilometres from an agricultural airstrip. The aircraft was being flown back to the strip at about 300 feet above ground level when suddenly, the engine developed a severe vibration. The pilot diagnosed a propeller blade failure and shut the engine down before it shook itself out of its mounts. The pilot chose the clearest area available for the forced landing, a sloping paddock covered in windrows consisting of recently bulldozed trees. The aircraft encountered one such heap of timber during its 60-metre ground roll. Post flight inspection found a 21-centimetre tip missing off one of the two propeller blades. Specialist metallurgical examination of the fracture surface indicated that the loss of the propeller tip was due to metal fatigue. The fatigue failure was initiated from an improperly blended mark caused by previous foreign object damage.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. Fatigue fracture of propeller blade.

2. Improper maintenance by maintenance personnel.

3. Forced landing on unsuitable terrain.