PILOT NAVIGATION
Senior/Master Air Cadet
4. MAP READING
Introduction
We have seen that despite the development of
very accurate navigation systems there is still
no substitute for map reading
However all of the errors that can be
made on the ground are just as likely to
be made in the air
Introduction
The extreme mental pressures in the airborne
environment demand that decisions have to
be made promptly
Therefore it is rare to navigate by map
reading alone - other equipment is used as
well
Weather
Is a major influence on the accuracy
of map reading, and at times may
prohibit its use
Weather
The lower the visibility, and the greater the
cloud cover, the more difficult the map
reading will be. At high altitude even
moderate cloud cover can make map reading
impossible
Aircraft Altitude
Has a major effect on map
reading requirements and
technique
Features which are ideal at low
level are useless at high level,
& vice versa
BAD
GOOD
Low Level
At low level it is important to chose
features that have vertical extent
CHIMNEYS
MASTS
WINDMILLS
SMALL HILLS
This is to enable them to be seen before the
aircraft arrives overhead the feature
High Level
At high level it is important to chose large
features that have definition and contrast
to stand out from a background
Lakes
Woods
Islands
A further consideration is the difficulty at
high level of obtaining an “on top” fix with
an aircraft of limited downward visibility
Unique Features
Very large errors can be introduced into map
reading simply by confusing one feature on
the map with another
For this reason villages are rarely used
We need more unique features
These can be
Power Stations
Bridges
Can you think of anymore?
Colour, Contrast & Season
Of all natural features, rivers and coast
lines are the most useful, especially in
poor weather
Why?
This is because they show the greatest
contrast & colour between themselves & the
land
Many land areas seen as ideal change their
appearance with the seasons.
A wood in the summer will not be as
obvious in the winter
A wooded area which
was used as a turning-point during
Summer Camp would be much more
difficult to identify in the winter when its
leaves had fallen
Snow changes everything including
man made features
Snow has a dramatic effect on
the landscape, eliminating many
features and rendering many of the
man-made line-features, such as
roads and railways, virtually invisible
Map Scales
In both military & civil aviation special
maps are produced for map reading
from the air
These differ from OS maps in that they
place more emphasis on those features
which are more easily identified from the air,
such as airfields, towns, railway tracks and
masts.
HOWEVER THEY MUST BE UP TO DATE !
HOWEVER THEY MUST BE UP TO DATE !
HOWEVER THEY MUST BE UP TO DATE !
The choice of scale of your chosen map
will depend on the speed of your aircraft
Most aircrew use the 1:500,000, widely
known as the “half million”.
In general, the slower you fly, and the
more detail you require, the larger scale
map you will use
For high-flying, long-range aircraft the
opposite is true
Here, smaller scale maps reduce the
number of sheets required
Map Symbols
FEET
METRES
3000
914
2000
610
1000
305
500
152
SEA
LEVEL
CIVILIAN
AIRFIELD
H
M
LIMITED
FACILITES
MICROLIGHT
G
MILITARY
HELICOPTER
AIRFIELD AVAILABLE
FOR CIVIL USE
H
X
DISUSED
PARACHUTING
825
(350)
UNLIT OBSTRUCTION & HEIGHT
(FIGURES ARE HEIGHT ABOVE
SEA LEVEL & (LOCAL GROUND LEVEL)
1978
(1031)
LIT OBSTRUCTION
B3 A FL45 -FL246
A
AIRSPACE BOUNDARY A
INDICATES THE AIRSPACE TYPE
IE A-F
REPORTING POINT
MANDATORY
ON REQUEST
E/E
BROOKLANDS
VRP
GUILFORD
SPECIAL ACCESS/
ENTRY EXIT
VISUAL REPORTING
POINT
VOR
DME
TACAN
NON-DIRECTIONAL
RADIO BEACON
Timing Marks
In a modern sophisticated aircraft the
navigation equipment will tell you where
to look if you become temporarily
uncertain of your position (i.e. lost!)
In a simple aircraft we will not have this
equipment and so rely on the stopwatch and
map
When planning a map reading flight it is
normal to put marks along each leg at a
set time - such as 2 minutes
If you lose your place along track while
map reading, consult your watch, work out
your time in minutes since the last point,
and that will tell you where to look on the
map.
A Tutor is flying from the railway
junction near Stowmarket via the mast
South West of East Dereham to the
lighthouse at Cromer
A route on a 1:50,000 map
from an initial point (IP) at
to a target on the river
near Allanton
Conclusion
In common with so many aspects of
aviation , successful map reading will
benefit greatly from the amount of
advanced planning
Through study of the route
detailed preparation of your route
and the careful selection of the unique
features on the ground
this will give you the best chance of
recovery when you lose your way