Navigation (General, Radio, Instrument)
Navigation
This domain covers general, radio and instrument navigation: map reading, dead reckoning, the wind triangle, VOR/NDB/DME, GNSS and instrument approach fundamentals.
General navigation. Convert between true, magnetic and compass headings: variation is the angle between true and magnetic north; deviation is the aircraft’s own compass error. “Variation east, magnetic least” means magnetic = true − easterly variation. Track is the path over the ground; heading is the direction the nose points; drift is the difference. Wind correction angle keeps the track correct.
Radio navigation. A VOR radial is a magnetic bearing from the station; the CDI centres when the selected OBS matches the radial, and TO/FROM indicates the direction relative to the station. NDB/ADF gives a relative bearing; DME gives slant range, which is greater than ground distance at high altitude. ILS has a localizer for lateral guidance and a glideslope for vertical guidance. GNSS/RNAV allows point-to-point navigation and requires RAIM checks for integrity.
Worked example
TAS 120 kt, track 360°, wind 270° at 30 kt. The crosswind component is 30 kt, so WCA = sin⁻¹(30/120) ≈ 14°. The wind is from the left, so heading = 360° − 14° = 346°. Groundspeed = 120 × cos 14° ≈ 116 kt.
Traps
Do not apply variation and deviation in the wrong order. Do not reverse the CDI sensing after passing a station. Do not treat DME as ground distance. Confirm RAIM before RNAV approaches.