An ATSB investigation report into the crash of an R44 Raven near Mudgee last year has concluded that the aircraft was overweight at the time.
The R44, VH-WOH, collided with terrain 20 km south-west of Mudgee during aerial agriculture operations on 9 December 2012. The pilot was fatally injured.
The wreckage was discovered after the aircraft had completed a number of spray runs, but failed to return to the filling station.
"The ATSB found that at the time of the accident the helicopter was over its maximum allowable weight," the report states, "was too heavy to hover out-of-ground effect and as the speed decreased, the power required exceeded that available from the engine resulting in a probable reduction in main rotor RPM (overpitch) and a descent.
"The time between this point and the first contact with a tree was insufficient for the pilot to complete a recovery action."
According to the report, the R44 weighed 1122 kg against a maximum take-off weight of 1089 kg.
The full report is on the ATSB website.