Navigation
This domain tests dead reckoning, charts, heading and track, wind triangle, magnetic variation/deviation, time/fuel planning and GPS use.
Core rules
True course is measured on the chart; true heading corrects for wind; magnetic heading applies variation; compass heading applies deviation. Track is the path over the ground. Groundspeed = distance ÷ time. Drift is caused by crosswind. GPS gives track and groundspeed but not automatically terrain clearance or legal airspace compliance.
Worked example
True course 000°, TAS 100 kt, wind from 270° at 20 kt. The wind pushes the helicopter east, so crab left. Wind correction angle = arcsin(20/100) = 11.5° left; true heading = 348.5°. Groundspeed = √(100² − 20²) = 98 kt. With 5°W variation, magnetic heading = 348.5° + 5° = 353.5°M. Check the drift direction: wind from the west pushes you right, so the heading must be left of track.
Traps
Applying variation in the wrong direction; using TAS as groundspeed; forgetting deviation; and trusting GPS track without checking airspace and terrain.