FlightDesk Aero / Question bank / PPL · Navigation / True to magnetic: applying variation
PPL · EASA 061 · Magnetism and compasses
True to magnetic: applying variation
You measure a true track of 095° on the chart. The local magnetic variation is 4°E. What is the magnetic track?
Explanation
Variation is the angle between true north and magnetic north. With an easterly variation, magnetic north lies east of true north, so every direction measured from it comes out smaller. The memory aid is: variation east, magnetic least; variation west, magnetic best. In the formula, T stands for true, M for magnetic and Var for the variation, east (E) or west (W).
Step by step
- Start from the true track: 095°T.
- Variation is east, so magnetic is least: subtract it.
- 095° − 4° = 091°M.
Why not the other answers
- 099° adds an easterly variation. That is the rule for westerly variation.
- 095° is still the true track: variation has not been applied.
- 087° subtracts the variation twice (095 − 8).
Tip. Variation comes from the isogonals printed on your chart. It changes slowly over the years, so use a recent chart.
Original questions written by FlightDesk Aero and aligned with the EASA syllabus. They are not questions from the official EASA exam bank.