Navigation
Navigation tests position, direction, charts, dead reckoning, radio navigation and area navigation. The examiner expects correct application of variation and deviation and a clear understanding of what each navigation aid actually provides.
Core navigation
- Earth coordinates: latitude and longitude; great-circle routes are shortest, rhumb lines are constant track.
- Magnetic direction: true course ± variation gives magnetic; magnetic ± deviation gives compass. East variation is subtracted from true to get magnetic; west is added.
- Dead reckoning uses heading, true airspeed, wind and time. The wind triangle converts heading and TAS into track and groundspeed.
- VOR gives bearing; DME gives slant range; NDB gives relative bearing; ILS gives lateral and vertical guidance.
- GNSS/RNAV supports PBN, but database validity, RAIM and mode selection matter.
Worked example
True course 090°, variation 5°E, deviation 2°W. Magnetic course = 090 − 5 = 085°. Compass course = 085 + 2 = 087°. The order matters: apply variation to true, then deviation to magnetic. A common error is to add east variation.
Traps
Mixing true, magnetic and compass; reversing variation sign; treating DME as ground distance rather than slant range; and assuming GNSS is always available without checking RAIM or database status.