O-2024
Navigation and Position Determination for
Scanners
Minnesota Wing Aircrew Training:
Task O-2024
O-2024
Navigational Terms
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Navigation Terms

Course - planned or actual path of the
aircraft over the ground
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True course
Magnetic course
Heading - direction the aircraft is pointing
Drift - the effect of wind
Drift correction - degrees added to or
subtracted from aircraft heading
Nautical mile (nm) - measurement used in
air navigation
Knots (kts) - nautical miles per hour
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Longitude and Latitude
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Latitude and Longitude
Where they cross defines a
point on the earth
 By convention, latitude is
stated first
• Latitude is Based on Earth’s
motion
• Axis of rotation defines
poles and Equator
• Arbitrary point of Greenwich,
England was chosen for ‘prime
meridian’.
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O-2024
North Latitudes
Latitude
Equator
South Latitudes
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Parallels
Measure How Far North or South of Equator
Zero Degrees is Equator
“90 Degrees North” is the North Pole
“90 Degrees South” is the South Pole
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West Longitude
Prime Meridian
East Longitude
Longitude
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Half Great Circles Intersecting at the Poles
Measure How Far East or West of England
Zero Degrees is Prime Meridian (England)
Numbers between 0 and 180 are either East or West
Longitude
180 Degrees is opposite side of globe from England
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near international date line in Pacific Ocean
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Where’s Minnesota?
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Twin Cities
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Northern Minneapolis is at 45
Degrees North (half way
between the Equator and
North Pole!)
93 Degrees West is roughly
the Eastern edge of St. Paul.
The Northwest corner of the
state:
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Exactly 49 Degrees North
Roughly 97 Degrees West
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How Big is One Degree?
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
Degrees of Latitude are always the same
distance apart, about 60 Nautical Miles
Degrees of longitude vary in distance – near
the poles the lengths are quite small.
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In Minnesota, a degree of longitude is about 40 to
44 Nautical Miles across
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Dividing Degrees into Smaller Units
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A ‘Minute’: 1/60th of a Degree
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roughly a mile in size
Minutes are usually broken down into tenths of
minutes
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Alternatively, a ‘Second’ is 1/60th of a minute
O-2024
Expressing Latitude and Longitude
in Degrees and Minutes
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Small high circle after number denotes degrees
Apostrophe after number denotes minutes
Example:
Minneapolis Flying Cloud Airport
44o 49.63’ N 93o 27.43’ W
read as…
44 degrees 49.63 minutes North
93 degrees 27.43 minutes West
O-2024
Lines of latitude and longitude on sectional chart
Lat/Long on chart
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Determining Coordinates from a Chart
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Magnetic Variation
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Expressing Direction:
The Compass Rose
360
330
30
N
300
270
60
W
E
240
90
120
210
S
180
150
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Magnetic Variation
PHYSICAL POLE
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The magnetic pole
and physical pole
are not co-located
The difference in
heading for the two
poles is measured
and referred to as
magnetic variation
Near the magnetic
pole the difference
can be substantial
MAGNETIC POLE
O-2024
Magnetic Variation in the US
Westerly Variation
Easterly Variation
-15º
-10º
-5º
-0º
+25º
+20º
+15º
+5º+10
º
Agonic Line
O-2024
Lines of Variation on a
Sectional Chart
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Converting True Course to
Magnetic Course
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For East Variation, subtract from True Course
True Course – Variation = Magnetic Course
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For West Variation, add to True Course
True Course + Variation = Magnetic Course
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Mnemonic: “East is least, West is best”
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“Least” should make you think of subtraction
Rule is reversed if one wishes to convert a Magnetic
course to a True course.
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Airspace
O-2024
Special-Use Airspace

Military Operating Area (MOA)
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Military Training Routes
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Military may be conducting high-speed operations
VFR aircraft are not prohibited
Instrument routes (IR)
Visual routes (VR)
Restricted Areas
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Military may be conducting air-to-ground bombing or
gunnery practice
No other aircraft are allowed
O-2024
Sectional Charts
O-2024
Chart Reading

Sectional Aeronautical
Charts
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1 to 500,000
Medium to slow speed
aircraft
Types of Information
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Topographical
Aeronautical
Legend
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Sectional Charts
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Publication Schedule
Legend changes somewhat over time
Four Charts Needed to Cover Minnesota
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Twin Cities
Omaha
Green Bay
Chicago
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Sectional Chart Contents

Physical Geographic Features
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Areas: Water, Cities
Lines: Roads, Power Lines, Railroads
Landmarks: Race Tracks, Lookout Towers
Vertical obstructions
Maximum Elevation by Quadrangle
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Sectional Chart Contents
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Aeronautical Features
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Airports
Airspace Boundaries
Radio Navigation Facilities
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Airport legend
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Airport
data
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Radio Aids
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Topographic,obstructions and miscellaneous
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Chart Interpretation
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Railroad
Seaplane Base
Power Line
Airport
2 paved runways
Weather on 118.375MHz
Field elev. 1424
Traffic Frequency 123.0 MHz
Fuel available
Maximum
Elevation
Figure
Vertical
Obstruction
(2549 Ft. MSL, 1192 Ft. AGL)
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Airport with Control Tower
Low Level
Military Training Route
Lookout Tower
Parachute Jump Area
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Airport
Special Use
Airspace
no paved runways
fuel available
Restricted Airspace
Military Airport
With Control Tower
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Class ‘B’ Airspace
Class ‘D’ Airspace
Ultralight Area
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NDB
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VOR/DME
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Pilotage and Position
Determination
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Pilotage
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Navigation by visual cues
Uses recognizable landmarks
Correlate with sectional charts
Takes practice
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Familiar things look radically different from the air
Seasons make a difference, especially winter
Be careful using lakes – be sure of the shape and placement
next to other features
Difficult to use in sparse areas
Difficult at night
O-2024
Pilotage tricks

Tricks:
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Look for trees
to find creeks,
rivers, and
towns
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Position Determination

Sectional or Map
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Work from larger to
smaller
Work from a known
location to present
location
Watch the scale on
maps
Remain suspicious if all
points don’t seem to
line up right
Use groups of 3
characteristics to verify
position
O-2024
Keeping Track of
Position
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Maintain positional awareness from
takeoff to landing
Finger on the map method using visual
landmarks
If necessary, ask the pilot or observer to
determine position using GPS and/or
VOR
O-2024
Where are you?
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Low Level Navigation
O-2024
Low Level Navigation
THE DANGER
 The biggest single problem is crew workload
 Your perception of speed varies with altitude
SPECIAL ATTENTION
 Man-made obstructions
 Air crew duties
 These items should be covered during the
briefing.
O-2024
Obstacles and Other Dangers
WAKE TURBULENCE
O-2024
Obstacles and Other Dangers
TALL TOWERS
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Obstacles and Other Dangers
POWER LINES
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Obstacles and Other Dangers
LOW-FLYING, HEAVY AIRCRAFT
O-2024
CAP Grid System
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CAP Grid System
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Overlays standard sectional maps
Subdivides the map into distinct working areas
Each grid is 1/4° of latitude by 1/4° of longitude
(15 minutes square) and is assigned a number
A grid is identified by a Sectional Chart name plus a
number
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Example: Twin Cities Grid 444
(St. Cloud Area)
Grids are further divided into sub-grids labeled
A, B, C, and D
Each sectional has a standard for assigning
grid numbers — for areas of overlap the grid
number of the most westerly chart is used
O-2024
Sectional Grid System
46 o 00’ N
30’ x 30’
Aeronautical
Chart Divison
45 o 30’ N
94 o 00’ W
93 o 30’ W
O-2024
Sectional Grid System
46 o 00’ N
15’ x 15’
15’ x 15’
45 o 45’
15’ x 15’
15’ x 15’
45 o 30’ N
93 o 45’
94 o 00’ W
93 o 30’ W
O-2024
CAP Grid System
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A grid can be divided into
quarter grids
7 ½ Minutes square in
size
Quarter-grids are labeled
A, B, C, and D
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Example:
Twin Cities Grid 159A
(The Northwest quarter
of TC Grid 159)
Letters are used to
define sub-grids
159 ADB
159 A
102-15 W
102-00 W
36 15’ N
A
C
B
A
B
C
D
B
36-07.5’ N
102 11.25 W
D
C
36-00 N
102-07.5 W
102 15’ W
102-00 W
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Standardized Latitude/Longitude
Grid System
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This system does not
require special
numbering
Lat-long of lower right
corner defines the
grid
Letters are used to
define sub-grids
36/102 AA 36/102 ADB
103-00 W
102-00 W
37-00 N
A
B
C
A B
B
C D
36-30 N
102-45 W
D
C
36-00 N
102-30 W
103-00 W
102-00 W
O-2024
Making Grid Charts
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You can use a new sectional — normally not
updated unless it gets worn out
Use a hi-lighter (not pink) to mark grid
boundaries on the chart using a long ruler
Mark grid identification in black ink for easy
visibility
You should always keep a current sectional
with you even if you have a sectional which is
marked with grids