VOR Approach Procedures
So let's now learn how to fly a VOR approach with another simulated example. Specifically, we will fly the Shelbyville, TN (KSYI) VOR/DME 18 approach. The approach requires both a VOR receiver and a DME receiver. There are variations of the VOR approach which require only the VOR receiver, or sometimes other miscellaneous equipment requirements. In any case, for this one we need both VOR and DME, though the DME will not be represented in our panel pictures below.
Here is the approach we will fly. Please note the chart is expired and should not be used for any navigational purpose. It is for illustration only.
So here is our setup. We are north of the approach course, and since we only have one choice for an initial approach fix (GRAMA), we will be using that.
GRAMA is identified as the 5 nm DME fix along the 340 radial off the SYI VOR. So the best thing we can do now to help identify that fix is to intercept the 340 radial and fly it inbound (heading of 160°) until we reach the 5 DME, by which we identify GRAMA.
So the 340° radial, we see, is to our right as expected. Let's turn to 180° in order to intercept it and track it inbound. Here's our simulated 172 panel:
And our Bonanza with an HSI:
And here we have intercepted the 340° radial and we are tracking it inbound on the reciprocal heading of 160°
Our HSI shows the same:
And our GPS shows GRAMA dead ahead on this radial. Now all we have to do is wait until our DME (not shown here) displays 5nm and we will have identified GRAMA and can begin an outbound turn.
Having passed GRAMA, we turn right (on the protected side), reintercept the 340° radial outbound, and execute the procedure turn. This isn't strictly necessary if your altitude, airplane, speed, and approach clearance allow you to safely descend to minimums starting from GRAMA. In our case, we are at 3500 feet and will require more space than we have between GRAMA and the runway to get the airplane to minimums. Thus we fly the procedure turn.
Here we are in the 172 turning right to the 340° radial outbound:
And our Bonanza HSI shows the equivalent turn:
So here's the trick... we cannot just turn to a 340° heading because then we will parallel the radial, rather than intercepting it. So we actually turn to a heading past 340°. Our heading of 010° here should provide us a nice 30° intercept, which is almost universally a good angle.
We show the same on the HSI below. Actually, the HSI gives us a more clear representation of what we are doing with regard to our desired course.
And sure enough, we have intercepted the radial here, so we can turn left to a heading of 340° (assuming no wind) and track the radial outbound. We will do this for 1-2 minutes, depending on the speed of the airplane we're flying. One minute in the 172 will be sufficient.
Our HSI shows we intercepted exactly like the OBS above:
Having now intercepted the radial and tracking it outbound, our approach chart now shows we can descend to 3,000 ft so we start that here.
Descending to 3,000 feet here too:
After tracking outbound for a minute, we turn left to 295° to start the procedure turn. At the beginning of the turn, reset the clock and time for another minute.
Turning to 295° on an HSI:
After flying for one minute on a 295° heading, do a 180 to the right to heading 115° as depicted on the chart at the procedure turn. Also, set the OBS or HSI course to the inbound approach course of 160°. That's very important - if you forget, you will get reverse sensing as you make corrections on the inbound approach course.
Again, the HSI provides a very clear picture of what is happening, and where we are with respect to the course. Please note that this shot is taken at the same location as the above one with the OBS.
Here we've established ourselves inbound on the 160° approach course, so we can turn right to 160° (again, in a no wind condition). According to the chart, we can also descend to 2300 until we pass GRAMA.
Our HSI panel at the same point:
We then level off at 2300 until passing GRAMA, maintaining our course.
Again, level at 2300 until GRAMA.
After we pass GRAMA, we can descend to the MDA of 1220.
Descending to minimums.
Of course, you must level off at the MDA if the runway environment is not in sight. Once you reach the missed approach point (MAP), which is identified by 0.3 DME, if you do not yet have the runway in sight or you are not able to make a normal descent to landing, execute the missed approach procedure.
For this approach, the missed instructions are: Climb to 2000 then climbing right turn to 3000 via SYI R-340 to GRAMA/5 DME and hold. You would perform a parallel hold entry, in this instance.
- Setting CDI to reciprocal resulting in FROM indication and reverse sensing
- Improper wind correction
- Descending too early or late
- Turning to wrong heading in procedure turn
- Forgetting to set the CDI to inbound approach course on procedure turn
ACS Test Standards
- Altitude +/- 100 feet
- Heading +/- 5°
- Airspeed +/- 10 knots
- CDI within 3/4 scale deflection