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Minnesota Wing Aircrew Training: Task O-2024

Navigation and Position Determination for Scanners

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Navigational Terms

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Navigation Terms Course - planned or actual path of the aircraft

over the ground– 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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Latitude

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

North Latitudes

South Latitudes

Equator

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Longitude

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

– near international date line in Pacific Ocean

East LongitudeEast LongitudeWest LongitudeWest Longitude Prime Meridian

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Where’s Minnesota?

Twin Cities – 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:

– Exactly 49 Degrees North– Roughly 97 Degrees West

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How Big is One Degree?

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.– In Minnesota, a degree of longitude is about 40 to

44 Nautical Miles across

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Dividing Degrees into Smaller Units

A ‘Minute’: 1/60th of a Degree – roughly a mile in size

Minutes are usually broken down into tenths of minutes– Alternatively, a ‘Second’ is 1/60th of a minute

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Expressing Latitude and Longitude in Degrees and Minutes

Small high circle after number denotes degrees Apostrophe after number denotes minutes Example:

Minneapolis Flying Cloud Airport44o 49.63’ N 93o 27.43’ W

read as…44 degrees 49.63 minutes North 93 degrees 27.43 minutes West

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Lat/Long on chart

Lines of latitude and longitude on sectional 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

N

90270

180

330 30

210

120

60

150

300

240S

W E

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Magnetic Variation 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

PHYSICAL POLE MAGNETIC POLE

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Magnetic Variation in the US

-15-15ºº-10-10ºº -5-5ºº -0-0ºº +5+5ºº+10+10ºº

+15+15ºº+20+20ºº

+25+25ºº

Agonic LineAgonic Line

Easterly VariationEasterly Variation Westerly VariationWesterly Variation

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Lines of Variation on a Lines of Variation on a Sectional ChartSectional Chart

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Converting True Course to Magnetic Course

For East Variation, subtract from True CourseTrue Course – Variation = Magnetic Course

For West Variation, add to True CourseTrue Course + Variation = Magnetic Course

Mnemonic: “East is least, West is best”– “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

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Special-Use Airspace

Military Operating Area (MOA)– Military may be conducting high-speed operations– VFR aircraft are not prohibited

Military Training Routes– Instrument routes (IR)– Visual routes (VR)

Restricted Areas– Military may be conducting air-to-ground bombing or

gunnery practice– No other aircraft are allowed

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Sectional Charts

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Chart Reading

Sectional Aeronautical Charts

– 1 to 500,000– Medium to slow speed

aircraft Types of Information

– Topographical– Aeronautical– Legend

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Sectional Charts

Publication Schedule Legend changes somewhat over time Four Charts Needed to Cover Minnesota

– Twin Cities– Omaha– Green Bay– Chicago

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Sectional Chart Contents

Physical Geographic Features– 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

Aeronautical Features– 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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AirportAirport2 paved runways2 paved runwaysWeather on 118.375MHzWeather on 118.375MHzField elev. 1424Field elev. 1424Traffic Frequency 123.0 MHzTraffic Frequency 123.0 MHzFuel availableFuel available

Seaplane BaseSeaplane Base

Vertical Vertical ObstructionObstruction(2549 Ft. MSL, 1192 Ft. AGL)(2549 Ft. MSL, 1192 Ft. AGL)

RailroadRailroad

Power LinePower Line

MaximumMaximumElevationElevationFigureFigure

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Airport with Control TowerAirport with Control Tower

Parachute Jump AreaParachute Jump Area

Low LevelLow LevelMilitary Training RouteMilitary Training Route

Lookout TowerLookout Tower

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Military AirportMilitary AirportWith Control TowerWith Control Tower

Restricted AirspaceRestricted Airspace

Special Use Special Use AirspaceAirspace

AirportAirportno paved runwaysno paved runwaysfuel availablefuel available

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Ultralight AreaUltralight Area

Class ‘D’ AirspaceClass ‘D’ Airspace

Class ‘B’ AirspaceClass ‘B’ Airspace

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NDB

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VOR/DME

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Pilotage and Position Determination

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Pilotage

Navigation by visual cues Uses recognizable landmarks Correlate with sectional charts Takes practice

– 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

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Pilotage tricks

Tricks:– Look for trees

to find creeks, rivers, and towns

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Position Determination Sectional or Map

– 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

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Keeping Track of Position

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

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Where are you?

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Low Level Navigation

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Low Level Navigation

THE DANGER The biggest single problem is crew workload Your perception of speed varies with altitudeSPECIAL ATTENTION Man-made obstructions Air crew duties These items should be covered during the

briefing.

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Obstacles and Other Dangers

WAKE TURBULENCE

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Obstacles and Other DangersTALL TOWERS

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Obstacles and Other DangersPOWER LINES

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Obstacles and Other DangersLOW-FLYING, HEAVY

AIRCRAFT

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CAP Grid System

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CAP Grid System 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

– 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

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Sectional Grid System

94 00’ W o 93 30’ W o

45 30’ No

46 00’ No

30’ x 30’Aeronautical Chart Divison

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Sectional Grid System

93 45’ o

94 00’ W o 93 30’ W o

45 30’ No

46 00’ No

45 45’ o

15’ x 15’ 15’ x 15’

15’ x 15’ 15’ x 15’

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CAP Grid System A grid can be divided into

quarter grids 7 ½ Minutes square in size

Quarter-grids are labeled A, B, C, and D– Example:

Twin Cities Grid 159A(The Northwest quarter of TC Grid 159)

Letters are used to define sub-grids

102-15 W

102 15’ W

102-00 W

102-00 W

36-00 N

36 15’ N

A B

CB

C D

159 A

36-07.5’ N102 11.25 W

102-07.5 W

A B

C D

159 ADB

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Standardized Latitude/Longitude Grid System

This system does not require special numbering

Lat-long of lower right corner defines the grid

Letters are used to define sub-grids

103-00 W

103-00 W

102-00 W

102-00 W

36-00 N

37-00 N

A B

CB

C D

36/102 AA

36-30 N102-45 W

102-30 W

A B

C D

36/102 ADB

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Making Grid Charts

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