T
he real beauty of aviation is the
fact that, once airborne, we are
not bound by those physical
boundaries such as mountains,
rivers, sand dunes, lakes and
oceans that present a logistical
nightmare to parties in land-based
vehicles wishing to explore the
content of our vast expanse of
land. From an aircraft, you can
explore a massive tract of land
or water, the size of which is
limited only by that aircraft’s fuel
endurance and the location of the
next fuel pump.
One of Australia’s greatest
assets is, and has always been,
the variety and wealth of mineral
deposits which exist across the
entire length and breadth of our
nation. The greatest problem
that our mining companies have
ever faced is identifying the
exact location of those bountiful
deposits prior to arranging their
physical extraction.
That problem has been
mitigated significantly by using
aircraft carrying innovative
sensory equipment. Today aircraft
can f ly in grid patterns above
areas of interest in order to createextremely detailed "charts" of
the geophysical structure and
composition of the earth’s crust
to a depth of up to 10 kilometres
below the surface.
This corner of general
aviation has grown into a highly
competitive and extremely
dynamic industry of its own. A
wide range of aircraft have been
used for surveying the mineral
content within our vast landscape
for many decades. As technologies
have improved, both in aviation
and in geophysical data acquisition
equipment, greater advantage is
consistently made available to the
mineral exploration industry and
their many varied clients.Getting technical
The life of an airborne
geophysical survey pilot is
an interesting one to say the
least. There is no limit to the
possibilities of where they might
be sent to f ly their next low-level
acquisition lines. From the wind
swept southern tip of Tasmania
to the sun-bleached archipelago
of Australia’s North West Shelf,
and throughout all of the parchedred centre in between, a survey
pilot will have the chance to see it
all. Further, and equally exciting,
destinations to which geophysical
survey pilots and crews are posted
include all other corners of the
world, without exception.
Frequenting those places where
the average Australian or foreign
tourist might plan to visit once
in a life time, survey pilots also
often find themselves in bizarre
yet beautiful surrounds that
others would never otherwise
visit, let alone see in their entirety
from an aircraft at low level.
The windscreen of a survey
aircraft reveals a constantly
changing kaleidoscope of either
sheer beauty and wonder or a
repetitively harsh and hostile
landscape.
Historically, magnetic and
radiometric surveys have
constituted the greater portion
of the exploration client’s
specification requirements.
These surveys are f lown at levels
varying from 50 to 200 feet
AGL depending on the required
resolution of the resulting
data. The aircraft are fittedMasters of all they
Survey Flying ROHAN WILLIAMS
Aerial survey work requires pilots that can ly
precision lines regularly at low level. According to
pilot Rohan Williams, it requires high levels of skill
combined with a Trojan work ethic to make the grade.
38
AUSTRALIAN FLYING July – August 2018Survey
with either one or a series of
magnetometers which precisely
measure the variation in the
magnetic ambience across the
tract of land specified by the
client. The magnetometers are
always mounted at an extremity
of the airframe in order to isolate
them as much as possible from
the engine and other components
within the aircraft that produce
magnetic interference and thereby
reduce the resultant resolution of
the magnetic data acquired.
Radiometric data is acquired by
carrying a spectrometer, with its
sensor pack usually mounted as
close as possible to the belly skin
of the aircraft.
With the aircraft’s data
acquisition system taking
millisecond readings, those
readings are collected, recordedSTEVE HITCHEN