Navigation
Navigation tests pilotage, dead reckoning, charts, wind triangle, magnetic direction, radio navigation, and GPS use. The exam expects precise arithmetic and a clear understanding of true, magnetic, and compass directions.
Core rules
- Direction: true direction is measured from true north; magnetic from magnetic north; compass from the cockpit compass. Variation is the angle between true and magnetic; deviation is the compass error.
- Conversion: use east is least, west is best: to go from true to magnetic, add westerly variation and subtract easterly variation. Apply deviation similarly for compass.
- Wind triangle: true course and TAS plus wind direction and speed give true heading and groundspeed. Then apply variation and deviation.
- Time, distance, fuel: time = distance ÷ groundspeed; fuel = consumption × time. Always keep units consistent.
- Radio navigation: a VOR radial is a magnetic bearing from the station; GPS gives track and groundspeed but not automatically obstacle clearance.
Worked example
True course is 090°, variation 7°W, deviation 2°E, no wind. Magnetic course = 090 + 7 = 097°. Compass heading = 097 − 2 = 095°. The reasoning: westerly variation means magnetic north lies west of true north, so the magnetic value is larger; easterly deviation means the compass reads less than magnetic. With wind, you would first calculate true heading and groundspeed, then apply the same corrections.
Traps
Do not apply variation to a heading that is already magnetic, or mix course and heading. A wind from the left requires a heading into the wind, not away from it. Do not use TAS as groundspeed. Chart symbols and airspace boundaries can change; use current charts.