Robinson R22-B, VH-KSI, 100 km south-east of Darwin, Northern Territory, on 16 October 1989

Circumstances:

The pilot was engaged in mustering pigs for aerial culling. On spotting a group of animals, he flared the helicopter from about 50 knots to a slow speed and then banked hard to the left at low level. The main rotor blade tips struck long grass and the helicopter rolled over and came to rest on its left side. The area of operations comprised a virtual " sea of grass ", unrelieved by any trees or other vegetation. Judgement of height above the ground under such conditions is more difficult than usual. The manoeuvre flown by the pilot would have exacerbated the problem.

Significant Factors:

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

1. Featureless terrain.
2. Pilot misjudged height above the ground during a rapidly executed turn.