Navigation: Flight Planning, Charts and Wind
Core planning chain
Navigation questions follow a chain: true course from the chart, wind correction to true heading, variation to magnetic heading, deviation to compass heading, then groundspeed and time. Pilotage confirms position by landmarks; dead reckoning uses time, speed and heading. Be able to read VNC/VTA scales, airspace, obstacles, magnetic variation lines and elevation contour intervals. Use UTC for flight planning and convert to local time only when needed; watch the date change across time zones.
Traps
The classic error is applying variation in the wrong direction. Remember “variation west, magnetic best; variation east, magnetic least.” Apply variation between true and magnetic, then apply deviation between magnetic and compass-these are separate corrections. Wind problems often give wind direction in true degrees, while ATIS may report magnetic; keep the reference frame consistent. Another trap is using true airspeed where groundspeed is required for ETA and fuel. Check units: nautical miles versus statute miles, gallons versus litres, and minutes versus decimal hours.
Worked example
True course 090°, variation 10°W, deviation 2°E, no wind. Variation west is added: magnetic course = 100°. Deviation east is subtracted: compass heading = 098°. If groundspeed is 120 kt, a 60 NM leg takes 30 minutes; fuel burn at 30 L/h would be 15 L. Rule of thumb: TC → MC → compass, applying west variation as a plus and east deviation as a minus.