The ATSB's final investigation report into an aircraft accident near Willowbank in Queensland last year, resulting in five deceased persons and two seriously injured survivors, found that the aircraft's performance prior to impacting a large tree and crashing into a dam was consistent with an engine power loss.
The Australian Transport Safety Bureau report states that technical examination of the Cessna 206's engine and its associated components did not reveal anomalies with the potential to have individually contributed to the partial engine power loss and loss of climb performance about 100 feet above ground level.
The investigation could not discount the potential that a number of less significant anomalies that were identified, may have coincided on 2 January 2006 to reduce the available engine power.
Laboratory examination of the fuel used in the aircraft was found to be outside specification. However, fuel quality experts that were consulted during the investigation indicated that there was minimal potential for the quality of the fuel to have negatively affected the engine's performance.
The investigation determined that the aircraft was being operated in an overweight condition, but because of limitations in the available performance information on the highly-modified aircraft, the effect of that overloading could not be quantified.
The report outlines safety action taken by the Australian Parachute Federation (APF) and contains seven safety recommendations to the APF, the Civil Aviation Safety Authority and the US Federal Aviation Administration to enhance future safety.
As a result of this and a number of other accidents involving partial engine power loss, the ATSB has initiated a special investigation into the factors that affect loss of control following engine power loss (including partial power loss) after takeoff.
Copies of the report can be downloaded from the ATSB's internet site at www.atsb.gov.au.