The Robinson R22 helicopter is the most common model of
rotary-wing aircraft on the Australian register and has been a
popular choice for private operations, flying training and various
types of aerial work activity. The R22 has a relatively good safety
record compared with other light piston-engine helicopters in
Australia based on activity levels.
The R22 is also the favoured type for aerial stock mustering
operations - an uniquely Australian application that supports the
local beef cattle industry. Despite its popularity in this type of
work, little was known about the helicopter's suitability for the
task. Like other helicopters on the Australian register, the R22
received its initial airworthiness certification in its country of
manufacture (United States). The spectrum of manoeuvres conducted
in aerial stock mustering did not form part of the flight profile
used when the helicopter type received its certification.
In 2004 the ATSB commissioned AeroStructures, an Australian
engineering company, to undertake a study of forces acting on an
R22 engaged in aerial mustering operations. AeroStructures Report:
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PDF: 750KB]
Their study offers some useful data on R22 flight profiles in
aerial mustering operations, and compares these with the flight
profiles used by Robinson Helicopter Company when the helicopter
was initially certified.
The AeroStructures testing showed that mustering operations can
involve large and sudden power changes that apply very high loads
on the helicopter's drive system, and these may exceed the limits
set during the certification process. Their report highlights the
importance of handling technique, and especially good engine
management.