The VOR

Radials, the OBS, TO/FROM, and intercepting a course.

15 min read · Navigation

After this lesson you can

  • Explain what a VOR radial actually measures, and why it does not depend on the aircraft's heading.
  • Read a CDI and OBS to identify a radial and fly to or from a station.
  • Use a time-distance check to estimate minutes remaining to a station.
  • Check a VOR receiver's accuracy the way 14 CFR 91.171 requires for IFR flight, and know why it matters in VFR too.

The VOR has guided American civil aviation since the 1950s, and it remains the backbone navigation system precisely because it does not depend on satellites: a ground transmitter broadcasts, and an aircraft receiver reads a bearing, nothing more exotic than that.

Its logic trips up beginners for one reason: a VOR does not measure anything about the aircraft's heading. It measures the aircraft's position relative to a radial the pilot has selected - a purely geographic fact, indifferent to which way the nose happens to be pointed at the moment.

The rest of this lesson

  1. 1.What a radial actually is
  2. 2.The cockpit instrument: OBS, CDI, TO/FROM
  3. 3.Tracking to a station
  4. 4.Finding your position from the air
  5. 5.DME and VOR/DME-based RNAV
  6. 6.Keeping the receiver honest

These 6 sections, their figures, the checks along the way and the end-of-lesson quiz come with the PPL track. Paid once, yours for good.

See what the PPL track costsEvery module 1 is free to read, no account, no card.

Key terms

Try to recall each definition before turning the card.