Instrument Flight: Navigation (radio navigation and area navigation)
What the exam tests
Navigation covers radio navigation and area navigation: VOR and DME, ILS, NDB, GNSS, RNAV and RNP, PBN, waypoints and CDI or HSI interpretation. Expect tracking, interception and database questions.
Core rules
- A VOR gives a magnetic radial from the station; the TO/FROM flag shows your direction relative to the station.
- DME gives slant range, not ground distance; error increases at high altitude.
- ILS: localiser gives lateral guidance; glideslope gives vertical guidance; DA or MDA depends on the approach type.
- NDB and ADF: relative bearing plus heading gives magnetic bearing; station passage is shown by the needle swing.
- RNAV: fly-by waypoints cut the corner; fly-over waypoints require overflight; RNP adds on-board performance monitoring and alerting.
- GNSS: RAIM checks integrity; without RAIM, some RNAV or non-precision operations may be unavailable.
Worked example
You are on the 090 radial, heading 090, and told to intercept the 060 radial inbound. Turn left to about 030 to intercept at 30 degrees; when the CDI centres with a TO indication, turn right to 060 and track. Turning the wrong way intercepts the reciprocal and can produce a large error.
Traps
- Confusing radial 'from' with bearing 'to'.
- Chasing the CDI instead of using a standard intercept angle.
- Forgetting that DME is slant range.
- Assuming the RNAV database is current without checking.