Navigation
Core concepts
Navigation covers chart reading, the Earth's coordinate system, magnetism, dead reckoning, the triangle of velocities, and flight planning. You must understand true versus magnetic versus compass headings, variation and deviation, and how to apply them. Know how to compute track, groundspeed, and wind correction using the triangle of velocities, and understand the properties of Mercator and Lambert conformal conic projections.
Traps to watch
Examiners love the sign conventions of variation and deviation: "variation east, magnetic least; variation west, magnetic best." A second trap is confusing track (path over ground) with heading (direction the nose points). Wind correction angle questions require careful drawing of the triangle. Remember that isogonal lines connect equal variation and that the agonic line has zero variation. Also watch for questions on great circles versus rhumb lines: a great circle is the shortest path but appears curved on a Mercator chart.
Worked example
True track 090°, variation 10°E. Magnetic track = 090° − 10° = 080°. If deviation is 2°W, compass = 080° + 2° = 082°.
Rule of thumb
East variation: subtract to go true→magnetic. West variation: add. Apply deviation last.