Navigation and Radio Aids: Dead Reckoning, Charts and Navaids
Core concepts
Navigation covers dead reckoning (heading, track, wind triangle), chart reading (scale, symbols, airspace), time/distance/fuel calculations, and radio navigation aids (VOR, DME, NDB/ADF, ILS, GNSS). Understand true vs magnetic vs compass headings and the corrections between them.
Traps
- Track vs heading: wind causes drift; the wind correction angle must be applied to convert track to heading. Questions often give wind and expect the crab angle.
- Variation vs deviation: variation is angular difference between true and magnetic north (from the chart); deviation is the compass error (from the compass card). "Variation east, magnetic least" - add easterly variation when converting true to magnetic? Check the mnemonic carefully: from true to magnetic, subtract easterly variation.
- VOR radials: a radial is from the station; the CDI centres when the selected radial matches your position line.
- DME gives slant range, not ground distance; error increases with altitude.
Worked example
True track 090°, variation 5°E, deviation 2°W. Magnetic track = 090 − 5 = 085°. Compass heading = 085 + 2 = 087° (deviation west, compass north is west of magnetic, so add). Rule of thumb: TVMDC - True Virgins Make Dull Company; Add Whiskey (west), Subtract East when going true→compass.
Study tip
Drill the TVMDC ladder until conversions are automatic; most navigation errors are sign errors.
Radiotelephony and Communications: Phraseology and Procedures
Core concepts
Radiotelephony tests standard phraseology, call signs, readback requirements, distress and urgency (MAYDAY, PAN PAN), emergency frequencies (121.5 MHz), and position reporting. Understand the communication sequence for departure, en route, approach and landing, and the use of transponder codes (squawk 7700, 7600, 7500).
Traps
- MAYDAY vs PAN PAN: MAYDAY is distress (grave and imminent danger); PAN PAN is urgency (no immediate danger). Never mix them.
- Readback: clearances involving runway, altitude, heading and frequency must be read back; omitting any element is an error.
- Transponder codes: 7700 emergency, 7600 radio failure, 7500 unlawful interference. Questions swap them.
- Call sign discipline: use the full call sign on initial contact, then abbreviated form only if permitted.
Worked example
You experience radio failure in controlled airspace. Rule of thumb: squawk 7600, continue per the last clearance or standard procedure, and land as soon as practicable; then report to ATC by telephone.
Study tip
Practise reading standard phraseology aloud; exams often test exact wording and readback completeness.