Radio Navigation and Instrument Flight
Navigation aids in depth
Know how each aid works and its limitations. VOR provides radials referenced to magnetic north; the CDI shows deviation from the selected course, and TO/FROM indicates whether the selected course leads to or from the station. NDB/ADF uses relative bearings and is subject to night effect, static and terrain errors. DME measures slant range, which over-reads ground distance at high altitude and close range. ILS combines a localiser for lateral guidance and a glide path for vertical guidance, with markers or DME for range. GNSS requires adequate satellite geometry and RAIM for integrity.
Instrument flight
Understand the instrument scan, partial-panel flying, and standard rate turns. Know the holding pattern entries and the wind correction needed to maintain the inbound and outbound legs. Understand approach plates: plan view, profile view, minima and missed approach.
Traps
A frequent trap is confusing a VOR radial with the aircraft heading, or forgetting that the CDI needle centres only when the selected course matches the aircraft's position relative to the station. Another is misreading DME as ground distance. In holds, examiners test the entry sector and the outbound timing.
Worked example / rule of thumb
Rule of thumb: the CDI needle deflects one dot per roughly 2° on a standard VOR, and the 1 in 60 rule converts degrees into distance. For holds, outbound leg timing is typically 1 minute at or below 14 000 ft and 1.5 minutes above, adjusted for wind.
Study strategy
Fly each approach on a simulator or sketch it on paper, labelling the guidance source for each segment.