The pilot was engaged on a survey flight for the owner of Coolibah Station, the operator of the helicopter. While flying at approximately 500 feet above ground level(agl) a turn downwind was initiated. The helicopter was close to maximum all up weight and it started to lose altitude. The pilot started to apply more power but the helicopter continued to sink and the rotor rpm decayed. The pilot saw a gap in the trees and attempted to land in it, however, the mainrotor hit a tree. The helicopter then slid along on the skids for approximately 10 metres before they dug into the ground and the helicopter nosed over. The pilot was engaged in conversation with the passenger and allowed himself to become distracted. He may have commenced recovery action too late. However, the helicopter was descending downwind which are conditions which predispose towards settling-with-power. Settling-with-power happens when the mainrotor is settling in its own downwash and additional power will not stop the descent. The pilot's statement that he was applying more and more power but that the helicopter kept sinking indicates that settling-with-power was likely. Part of the technique for recovery from settling-with-power is to increase indicated airspeed before increasing power. This accident was not the subject of a formal on scene investigation.
