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Navigation. First of 4 parts. Navigation. Part 1 Introduction to the ¼ and ½ million charts, the nautical mile and altimetry. Part 2 The compass, magnetism, compass headings. Part 3 Notams, airspace and flight planning. Part 4 Practical paper. Pulling it all together. . Navigation.
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Navigation First of 4 parts
Navigation • Part 1 Introduction to the ¼ and ½ million charts, the nautical mile and altimetry. • Part 2 The compass, magnetism, compass headings. • Part 3 Notams, airspace and flight planning. • Part 4 Practical paper. Pulling it all together.
Navigation Part 1 Charts • General description • Differences ¼-1/2Mil • The nautical mile • Vertical navigation
Navigation If the world is a sphere, how are we going to depict the detail with any accuracy onto a flat piece of paper? This problem has dogged cartographers over the centuries. Distortion of shapes, distances and angles causes serious problems for navigators.
Navigation Cylindrical projections have a large scale/ or shape distortion. The further away from the tangent the worse the distortion.
Navigation A typical “mercator” cylindrical projection
Navigation Conic projections have greater distortion further from the tangent. Lamberts conic projection minimises distortion by having “2” tangents.
Navigation • 1:250000 chart • More detail • Airspace to 5000ft amsl • 1:500000 chart • Less detail • Airspace to FL195 You must carry a chart, or airspace information for any flight Over 5 nautical miles from the site.
Navigation A Great Circle is a circle depicted on the earths surface which is centred about the centre of the earth. The equator and lines of longitude are examples of great circles A great circle route is the shortest distance between two places.
Navigation I minute of arc =1 nautical mile North pole 60 minutes in one degree Equator Circumference of the earth 360*60= 21600 nautical miles
Navigation North pole 10,000 kilometres Equator Circumference of the earth 4*10000= 40000 kilometres
Navigation • A statute mile is 8 furlongs (furrows long). • A furlong is 10 chains (surveyor chains) • A chain is 22 yards • A cricket pitch is one chain
Navigation • 1 nautical mile is 6076 feet • 1 statute mile is 5280 feet • 1 kilometre is 3281 feet SO…… • 1 knot is 1 nautical mile per hour • 1 knot is very nearly 100ft per minute • 1 n.m is approximately 2 km All very helpful for estimation purposes.
Navigation Great Circle (Longitude) Who needs the scale on the chart? 5 nautical miles Minutes
Navigation Words are important Height Altitude Level They all have a precise meaning in navigation. Check it out on the chart.
Navigation • Height is the vertical distance above a feature. • Altitude is the vertical distance above the sea. • Level is the vertical distance above the standard pressure level (1013.25 hPa)
Navigate Height Altitude Flight Level 1013 hPa
Navigation ALTIMETERS 998 Constant level 1028 1013 4050ft 4500 ft 4950ft Height agl Pressure altitude FL45 Altitude amsl QFE 998 Std pressure 1013 Airfield elevation 900ft QNH 1028 Mean sea level