and grouped with a precise GPS
location and time stamp. From
that grouping, a chart can be
created of both the magnetic
and radiometric signature of any
particular location creating its own
"shade" of saturation on the chart.
The images produced show a three-
dimensional model of the survey
area in quite remarkable resolution.
From the images and their
supporting data produced,
geophysicists are able to pinpoint
likely locations of the deposition
of mineral ore in which they are
interested. They can then mark
those locations for the next stage
of their exploration program
which involves physically drilling
for and extracting core samples
from those locations.
Increasing demand for
geophysical data acquired through
newer emerging technologies
represents that area of growth
within the airborne geophysical
survey industry. Gravity, Light
Detection and Ranging (LIDAR)
imagery, photographic (for digital
mapping) and electromagnetic
surveys are such mediums under
that increasing demand. Most
aircraft involved with these
emerging technologies are of
the light and medium wake
turbulence categories.
Most survey aircraft are fitted
with additional fuel tanks which
allow a greater and therefore more
efficient fuel endurance. The
fewer times the aircraft needs
to return to the base airstrip to
refuel, the greater the relative
time spent acquiring data over
the survey area. Some survey
aircraft are fitted with up toeleven hours of fuel endurance in
order to maximise this efficiency.
Such endurance also becomes
a virtue when it comes to long
international ferry legs.On the job
A day in the life of a survey pilot
begins during those magical
moments before dawn breaks and
first light allows the first f light
of the day to begin. During this
time the aircraft’s acquisition
equipment is checked, calibrated,
and set for the first acquisition
f light by the ground-based
field operator. Simultaneously,
the pilot conducts their daily
inspection and signs the aircraft’s
maintenance release before
strapping themselves into the
cockpit a for a 4-6 hour f light of
geophysical data acquisition.After the first take-off of the
day the pilot f lies directly towards
the radio metric test line, which
is usually at least 7 km long,
aligned with the direction of f light
between the base aerodrome and
the survey area, and is f lown twice
daily as a control check of the
diurnal variation in radiometric
activity. Any differences between
that data collected between the
morning and evening test lines
can be assessed for likely diurnal
variance and regarded as a
"leveler" against which the survey
radiometric data can be processed
after collection. The test line is
usually f lown at the same height
AGL as that specified for the
survey area.
With the test line f lown, the
pilot will then set course for the
survey area and, specifically, theaustralianflying.com.au 39
July – August 2018 AUSTRALIAN FLYING“low-level engine failure procedures should be well drilled ”
Many types are used
in survey work, but the
Pacic Aerospace Fletcher/
Cresco/750XL family has
proven particularly well
adapted to the work.