Navigation
What the Navigation paper tests
CPL Navigation checks your ability to plan and monitor a flight without relying solely on GPS: chart reading and scale, the wind triangle, heading conversions, ETA/fuel calculations, and position fixing. Expect numerical questions where one unit slip or a reversed sign costs the mark.
Core rules
- Wind direction is given as the direction from which the wind blows; the wind vector in the triangle blows towards the reciprocal.
- Convert with the T-V-M-D-C chain. From true to magnetic: variation east, subtract; variation west, add. From magnetic to compass: deviation east, subtract; deviation west, add.
- Groundspeed, not TAS, drives ETA and fuel: time = distance/GS; fuel = flow × time + reserves.
- On a chart, use the scale bar and check units (nm vs km); latitude minute ≈ 1 nm.
- Fix position by at least two independent sources: visual checkpoint plus bearing/distance, or GPS cross-checked against DR.
Worked example
True track 090°, variation 12°E, deviation 3°E, TAS 120 kt, wind 180°/30 kt (true), distance 180 nm, departure 10:00 UTC. Wind from 180 blows toward 360, so it is a beam wind from the right. To hold 090°T, head into wind: solve 120 cos H + 30 = 0, giving H ≈ 104.5°T. Groundspeed = 120 sin 104.5° ≈ 116 kt. Magnetic heading = 104.5 − 12 = 92.5°M; compass heading = 92.5 − 3 = 89.5°C. Time = 180/116 = 1.55 h = 1 h 33 min; ETA = 11:33 UTC.
Traps
- Applying variation to the wind direction instead of the heading; wind is usually reported true or magnetic-check the source.
- Adding easterly variation/deviation instead of subtracting.
- Using TAS for ETA when a headwind/tailwind exists; GS changes with heading.
- Mixing chart units or using the wrong scale bar division.
- Treating a single GPS position as a complete fix without DR cross-check. Always label headings and times with the correct reference.