Radio Navigation
Ground-based and satellite aids
Radio navigation questions cover VOR, DME, NDB and ADF, ILS, GNSS and the interpretation of the indications they provide. Understand what each aid measures, what the cockpit display shows, and the errors and limitations associated with each. Know how to determine position from a radial and distance, and how to fly an approach using the relevant guidance.
Traps
Common traps include confusing a radial from a station with a bearing to the station, and misreading the CDI sense or the glidepath indication. Another trap is assuming an aid is usable beyond its published range or when the receiver is not in the correct mode. Questions may also test the difference between lateral and vertical guidance.
Worked example
If you are on the 270 radial of a VOR, you are west of the station. The course to the station is the reciprocal, 090. To fly inbound, set the OBS to 090 and track the needle to centre.
Rule of thumb
A radial is measured from the station outward. To fly to the station, use the reciprocal of the radial.