Senior/Master Air Cadet 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

Has a major effect on map reading requirements and technique 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

For this reason villages are rarely used 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

A wood in the summer will not be as obvious in the winter 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 !

Most aircrew use the 1:500,000, widely known as the “half million”. 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 SEA LEVEL 3000 2000 1000 500 914 610 305 152 FEET METRES

CIVILIAN LIMITED FACILITES AIRFIELD M H MICROLIGHT G

MILITARY H HELICOPTER X AIRFIELD AVAILABLE FOR CIVIL USE DISUSED

PARACHUTING 825 (350) 1978 LIT OBSTRUCTION (1031) B3 A FL45 -FL246 UNLIT OBSTRUCTION & HEIGHT (FIGURES ARE HEIGHT ABOVE SEA LEVEL & (LOCAL GROUND LEVEL) 1978 (1031) LIT OBSTRUCTION AIRSPACE BOUNDARY A INDICATES THE AIRSPACE TYPE IE A-F B3 A FL45 -FL246 A

REPORTING POINT MANDATORY ON REQUEST

SPECIAL ACCESS/ ENTRY EXIT VISUAL REPORTING POINT E/E BROOKLANDS VRP GUILFORD

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.

2 4 6 8 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