Piper PA28-181, VH-NOR, Lake Burragorang, New South Wales, on 29 May 1990

Circumstances:

The aircraft was engaged on a navigational exercise from Bankstown to Dubbo via Bathurst and return. Due to unfavourable weather, it was decided at Bathurst to return to Bankstown. Approaching Katoomba at 4000 feet, deteriorating weather required a diversion south of track over Lake Burragorang and a descent to 3500 feet. Rich mixture was selected prior to the descent. When cruise power was reinstated at 3500 feet, the engine suffered a substantial loss of power. The instructor took control and carried out a trouble check, which included the selection of carburettor heat, but was unable to prevent a total loss of power. A glide approach was made towards the only cleared area, a road near the lake shore. During the glide, it became apparent the aircraft would not reach the road. The aircraft was ditched into the water, about 10 metres from the shore. All three occupants were able to evacuate the cabin and make their way to the shore. The reason for the engine failure could not be positively established. However, given the high relative humidity at 3500 feet and rich mixture setting, the loss of power was consistent with the effects of carburettor induction icing.

Significant Factors:

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

1. The aircraft was operating in conditions of high relative humidity.

2. The engine was operating at a rich mixture setting.

3. Complete loss of power in flight, probably due to carburettor induction icing.

4. Due to stress of weather, the aircraft was flown over terrain unsuitable for a forced landing.

This accident was not the subject of an on-scene investigation.