Electronic Radio Navigation VOR Lesson Diagrams VOR Steps Flying From a VOR to Intercept a Radial Finding Position by VOR Radials Half Angle Wind Correction

VOR Lesson Diagrams
North, centered needle, Reverse sensing, side, Region of ambiguity, Region of flag reversal, VOR flag reversal ,

#1 360's on 135 radial

#2 Begin heading North around the two square mile square.
Wind correction angle
Draw in instrument face and needled position and then fly to confirm drawing.

VOR STEPS
For a checkpoint For flying to a VOR
1. Set the frequency 1. Set the frequency
2. Ident the code (volume up/down) 2. Ident the code (volume up/down)
3. Set the OBS (FROM ) 3. Center OBS From
4. Confirm that the needle 4. Center OBS To
is on the side toward 5. Turn to heading of OBS
the station 6. Compare, OBS, HI, compass
7. Fly (through) the needle

Flying From a VOR to Intercept a Radial
1. Set frequency either to or from
2. Ident code (volume up/down) 1. Set frequency
3. Center OBS From 2. Ident code (volume up/down)
4. Turn to OBS Heading 3. Set OBS To or From
5. Confirm HI, OBS, compass 4. Turn toward needle on
6. Fly to the needle heading to give 30 to 45
7. You have flown through the VOR degree intercept angle off OBS setting
5. When needle centers turn to OBS heading/
6. Check OBS, HI, compass
7. Fly to needle

Finding Position by VOR Radials
This procedure is best done with two VORs but can, with practice be done using only one. Have your sectional folded so that both VORs are showing. Confirm that you have sufficient altitude for line of sight reception from both. Use of three VORs will give a triangle which should include your location.

Where am I?
1. Select frequency and IDENT
2. Set OBS CDI needle to center and FROM
3. Draw line from center of VOR compass rose on that bearing
4. Distance may be determined by DME, if available
5. For greatest position accuracy using single VOR fly the course line in or outbound.
6. Repeat steps 1, 2, 3, and 4 using a different VOR as nearly 90° to your original chart line as you can find and receive.
7. Where the two lines intersect is your position for a moment.
8. Doing steps 1 through 5 with dual VORs can be used to give you a series of positions and a flight line with wind effects without recourse to compass or E6B.
9. You are (were) at the point of intersection.
10. The longer this procedure takes the more you must figure into present position your airspeed and course.
11. A third VOR will usually form a small triangle of position.

Time to Fly to a VOR?
Simplified it requires only that you locate yourself on any VOR radial. Turn to right angle to that radial and time the number of seconds it takes to intercept a radial 10 degrees further ahead. Drop the last digit from the total number of seconds. The remaining digit(s) is the number of minutes it will take you to track to the station. No wind factored in.

Determine your radial on a VOR. Fly at right angles to that radial. Determine what radial will be 10 degrees ahead of your present radial. Set the OBS for that radial. Time in seconds how long it will take you to fly across the 10 degrees. Drop the last digit of that time. The remaining digits are the number of minutes it will take you to fly to the VOR without regard to wind. This should be practiced several times before you can rely on your figures.

Set in any radial from a VOR. Turn 90 degrees to that radial and take a time hack. Reset the OBS to lead your aircraft by 10 degrees. The number of seconds divided by 10 that it takes you to center the needle at the new OBS setting is the number of minutes (disregarding wind) it will take you to fly to the VOR.
1. Turn to right angles of the CDI centered course line and start timing in seconds.
2. Fly in this right angled direction until CDI has moved 10°.
3. Note time to nearest ten seconds. Drop the zero.
4. The remaining number is how long it will take you to turn and fly directly to the VOR without considering the wind.

Procedure (time to station)
1. No wind conditions
2. Established needle centered on radial and turn 90-degrees.
3. Center needle again and start timer. Assume 090 from
4. Set OBS ahead of flight direction by 10-degrees. 090 + 10 = 100 as new OBS setting
5. When needle centers stop timer. Assume 150 seconds elapsed time.
6. Drop the 0 and you get 15. It will take you 15 minutes to fly to the VOR.

This is a good exercise to practice at night with a FSS. This is so seldom done that you might call before flying to advise them of what you want to do. They are still required to maintain their proficiency in doing this. The specialist I just spoke to had not had a pilot ask for one in nine years.

Opinion
The question is a deliberately simplified application of the one-in-60 rule with the special rule-of-thumb case for 10 degrees. I think any CFI applicant who can't recognize a question based on the 1:60 rule doesn't have a full understanding of the art.

(The rule is that a one degree deviation makes the legs of the triangle about 60:60:1. For small angles you can simply multiply, so 10 degrees is 6:6:1. Hence 8 mins becomes 48 mins. 130kt is 2 miles a minute plus about
10%.)

I feel that it's important to be able to do this kind of mental arithmetic, even if you argue that (a) any time you're in the situation described, you're going to have DME (b) by the time you've remembered the 60:1 rule and done the right multiplication's you're in the next state.

Half Angle Wind Correction
The process of correcting for wind when flying a VOR or Localizer is similar to the guessing of a number between 1 and 30. The better you guess the correct heading to compensate for wind the fewer adjustments and guesses required. Even in strong winds a 30-degree correction will bring in a needle. Once the angle of heading required to bring in the needle has centered the needle, a new guess is required to select the heading that keeps the needle centered.

Half angle method begins with the aircraft heading, OBS, and compass in agreement either to or from the VOR. As the VOR needle moves, say to the right, it is showing that the aircraft is moving to the left of the selected radial. The pilot now must make the first of his guesses. From estimates or forecasts he chooses a heading no more than 30 degrees of intercept that will bring in the needle. Once the needle is centered a second guess is made that may keep the needle centered. If once again the needle moves off center another pair of guesses is made. Even the worst 'guesser' who begins with a 15 degree WCA (wind correction angle) should require no more than three pairs of guesses to keep the needle centered.

Be aware that winds do change so that even a WCA that works from one checkpoint may not work from the next. Changes of altitude can have the same effect. It is important that the pilot realize that the four times greater sensitivity of the Localizer than the VOR requires greater concentration to selection and heading holding. The basic process remains the same, however.

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