What happened
At 1157 on 19 July 2011, a PZL-Mielec M18A Turbine Dromader
aircraft, registered VH-FOZ, impacted terrain on a cotton station
about 23 km west-south-west of Dirranbandi, Queensland while
conducting a spraying flight. The pilot was fatally injured and the
aircraft was destroyed by impact forces.
What the ATSB found
The ATSB found that, for reasons that could not be determined with
certainty, the aircraft departed from controlled flight during a
turn at low altitude and the pilot was unable to recover before
impacting the ground.
The ATSB also identified a significant safety issue affecting
the safety of future spraying operations in turbine Dromader
aircraft: the potential for the aircraft's centre of gravity to
vary significantly depending on the weight in the aircraft's
chemical/spray tank and exceed the forward and aft limits during a
flight. This safety issue was unlikely to have contributed to the
accident as the aircraft was probably within the approved weight
and balance limits at the time of the accident.
Moreover, although also not found to have contributed to the
accident, there was an increased risk to the flight from the
aircraft's operation, at times, in excess of its published airspeed
and angle of bank limitations.
What has been done as a result
During the investigation, the Australian Transport Safety Bureau
worked with the Civil Aviation Safety Authority (CASA) and the
Aerial Agricultural Association of Australia to address the risk to
turbine Dromader aircraft of the potential for excessive movement
of the aircraft's centre of gravity as the contents of the
aircraft's chemical/spray tank are dumped or dispensed.
CASA and the owner/developer of the approval for operations at
weights of up to 6,600 kg, which had effect during the flight, took
action to improve operator and pilot understanding of the issue. In
addition, the owner/developer indicated that the design would be
reviewed to address any excessive centre of gravity variations.
Safety message
Although it was not contributory in this instance, the ATSB
highlights the importance of pilots maintaining their aircraft's
weight and balance within limits throughout a flight, and of
understanding the implications of changing weight and balance.
Similarly, the ATSB reaffirms the importance of being familiar with
and adhering to aircraft operational limitations.