How to intercept a VOR radial using an OBS CDI

By Rory Bennett (ATPL, FI: CPL, IR, ME, UPRT) · Published 15 May 2026

Tune and identify the VOR. Set the desired course on the OBS and confirm a TO indication. Pick an intercept heading between the course pointer and the dots in the direction of CDI deflection, normally 30° to 60° off the course. Calculate the wind-corrected heading using max drift and the clock code. Roll out from the intercept onto the wind-corrected heading based on closure rate[1].

Plan view of a VOR radial intercept outbound: course pointer set on the OBS, CDI centred, aircraft on track.

A worked-example walkthrough of the five-step intercept using an OBS CDI. Full transcript is below the video.

Video transcript

How to intercept a VOR radial using an OBS CDI. We'll start with a simple task: fly a course of 310 inbound to KTN. Step one, select, tune, identify, and display the VOR. Step two, set the course. Here the desired course relative to the station is 310, so select 310 with the OBS. You should see a TO indication. This is important: with the TO indication, you know it is in the correct sense. Step three, pick an intercept heading. This will be between the course and the dots in the direction of the CDI. Normally 30 to 60° depending on distance from the VOR. Here we'll go for 355°. Step four, calculate a wind-corrected heading to hold the course. Here the wind is 270° at 18 knots. At 120 knots true airspeed, max drift is 9°. 270° is 40° from 310°, so it's two-thirds of max drift, 6° correction into wind. A heading of 304°. All that's left is to pick the point to turn onto your wind-corrected heading based on closure rate.

What does it mean to intercept a VOR radial?

Intercepting a radial means joining a defined course over the ground that lies along a VOR radial (or its reciprocal), then tracking that course. The technique applies whether you are tracking inbound or outbound. For the distinction between a radial and a course, see how to track a VOR radial.

How do you tune and display the VOR?

Step one is the standard pre-use sequence: select, tune, identify, and display the VOR[1]. Tune the frequency, listen for the Morse identifier, and confirm the navaid is displayed on the CDI you intend to use.

How do you set the course on the OBS?

Step two: set the desired course relative to the station on the OBS. With the correct course set on an inbound intercept, you should see a TO indication. The TO indication is the sense check: it tells you the course is in the correct sense[1].

How do you pick an intercept heading?

Step three: pick a heading between the course pointer and the CDI dots, in the direction of CDI deflection. Normally 30° to 60° off the course, depending on distance from the VOR[1].

How do you calculate a wind-corrected heading for the course?

Step four: calculate a wind-corrected heading to hold the course once established[1]. Find max drift (60 ÷ TAS × wind speed), apply the clock code to the angle from course to wind, and apply the correction into wind. See the clock-code mental shortcut for the in-flight technique.

Step five: pick the point to turn onto your wind-corrected heading based on closure rate. Start the turn from the intercept heading at a point that brings the CDI to centre as you roll out[1].

Worked example: course 310 inbound to KTN

Task: Fly a course of 310 inbound to KTN[1].

Step 1: Tune KTN, identify, and display the VOR on the CDI.

Step 2: Set 310 on the OBS. Confirm a TO indication.

Step 3: Pick an intercept heading. The video uses 355° (45° off the course).

Step 4: Wind 270°/18 kt, TAS 120 kt. Max drift = 60 ÷ 120 × 18 = 9°. Angle from course 310° to wind 270° is 40°. Clock code: 40/60 = 2/3. Drift = 2/3 × 9° = 6°. Wind is from the left, so correct into wind: heading 304°.

Step 5: Hold 355° on the intercept. As the CDI begins to move, pick the point to turn onto 304° based on closure rate.

Common mistakes

Skipping the TO/FROM check after setting the course. A TO indication confirms the course is in the correct sense. A FROM indication on an inbound intercept means the course is the wrong way round (usually the radial set instead of its reciprocal).
Using a shallow intercept at long range. Normal intercept is 30° to 60° off the course; the steeper end suits longer range from the VOR, where the needle moves slowly and a small angle leaves you tracking parallel to the course.
Holding the intercept heading until the needle centres. The roll-out is judged on closure rate, not on the needle reaching centre. Start the turn early enough that the needle is just settling as you roll out on the wind-corrected heading.

Practise this in the simulator

Reading the theory only goes so far. The simulator lets you fly the scenario in your browser with realistic instruments and wind.

Practise in the Intercept Trainer

Check your understanding

Read each question, work out the answer in your head, then reveal to check. Retrieval beats re-reading.

Course 310 inbound to KTN, TAS 120 kt, wind 270°/18 kt. What is the wind-corrected heading?

Show answer

Max drift = 60 ÷ 120 × 18 = 9°. Angle from course 310° to wind 270° is 40°. Clock code: 40/60 = 2/3, so drift = 2/3 × 9° = 6°. Wind is from the left of course, so correct into wind: heading = 310° − 6° = 304°.

Same setup. With the CDI half-scale deflected to the right, what intercept heading would you pick?

Show answer

Between the course (310°) and the dots in the direction of deflection, normally 30° to 60° off depending on distance. The transcript example uses 355° (45° off the course, on the right side).

Frequently asked questions

What angle should I use to intercept a VOR radial?

Normally 30° to 60° off the course, in the direction the CDI is deflected. Steeper angles suit longer range from the VOR (where the needle moves slowly); shallower angles suit short range where the needle moves quickly.

When do I turn onto the wind-corrected heading?

Based on closure rate, not on the needle reaching centre. Start the turn from the intercept heading to the wind-corrected heading at a point that brings the needle to centre as you roll out.

Why must I see a TO indication when setting the course inbound?

The TO indication confirms the course is set in the correct sense. A FROM indication when you are trying to track inbound usually means you have set the radial value on the OBS instead of its reciprocal.

How do I calculate the wind-corrected heading?

Max drift = 60 ÷ TAS × wind speed. Take the angle from course to wind, apply the clock code (60° to 90° gives full max drift, 0° to 60° gives the angle as a fraction of 60), and apply into wind. See the clock-code for the in-flight technique.

Sources

Good Flying Made Easy, How to intercept a VOR Radial using an OBS CDI. youtube.com/watch?v=ArV1V9-P8-o

How to Track a VOR RadialTune, identify, set the OBS, and track a VOR radial inbound or outbound with wind correction. The ra...

This article does not constitute flight instruction. Always defer to the guidance of your qualified flight instructor and to current charts and procedures or regulations published by your country's aviation authority.