Tutorial: VOR Navigation
Provided by Joel Johnson and written by Jetjerry & Ottopilot
While the following tutorial was created using X-Plane, pilots of MSFS will also benefit from it, as the procedures are almost identical.
Important: links to the scenery mentioned in this tutorial are provided at the end of the tutorial.
The two airports mentioned in this tutorial are:
Springfield/Abraham Lincoln Capital Airport (KSPI)
Abraham Lincoln Capital Airport is a civil-military public airport in Sangamon County, Illinois. It is three miles (6 km) northwest of downtown Springfield, the capital of Illinois. It has three runways: 4/22 is 8,001 by 150 feet (2,439 x 46 m) concrete; 13/31 is 7,400 by 150 feet (2,256 x 46 m) asphalt; 18/36 is 5,300 by 150 feet (1,615 x 46 m) asphalt/concrete.
Champaign/University of Illinois Willard Airport (KCMI)
University of Illinois Willard Airport is south of Savoy in Tolono Township, Champaign County, Illinois. Willard Airport covers 1,799 acres and has three runways: runway 4/22: 6,501 by 150 ft (1,982 by 46 m) concrete, runway 14L/32R: 8,102 by 150 ft (2,469 by 46 m) concrete with ILS, runway 14R/32L: 3,817 by 75 ft (1,163 by 23 m) asphalt.
EPOCH IFR
Purpose: To familiarize yourself with VOR radio navigation.
VHF omnidirectional radio range (VOR), is a type of short-range radio navigation system for aircraft, enabling aircraft to determine their position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons, with a receiver unit. It uses radio frequencies in the very high frequency (VHF) band from 108 to 117.95 MHz.
This line of position is called the "radial" from the VOR. The intersection of two radials from different VOR stations on a chart provides the position of the aircraft. VOR stations are fairly short range: the signals have a normal range of between 25 - 200 miles.
Below are the three types found on charts.
Scenario:
You are at KSPI (Springfield, IL) and you wish to fly to KCMI (Champaign, IL). The weather is just above basic VFR (Visual Flight Rules [1000' & 3sm]), but you don't want to fly that low, so you file an IFR (Instrument Flight Rules) flight plan so you can make the trip at a higher altitude. You plan to descend to VFR conditions upon arrival and land visually.
You will follow Low Altitude Airways ("Victor" airways - as they are preceded by a "V" on the Low Altitude Charts), i.e. V10.
Setup:
- Route: KSPI - V50 - AXC - V251 - KCMI
- Altitude: Between 5000 - 17,000 feet. Your choice depending on aircraft.
- Weather: Your choice. No wind. (suggest you fly this several times with progressively lower weather). Try using a ceiling of 3000 feet and a visibility of 3.5 miles when you think you have it mastered.
- Aircraft: Any airplane.
KSPI Airport Chart:
Low Altitude Enroute Chart (Segment between KSPI - KCMI): Chart L-27
Note: I suggest you print out a clean copy of the Low Chart segment for this flight. Chart: L-27
VFR Sectional Chart with route plotted.
Link to NavPlan Flight Planner site.
Build your own paper E6B aviation computer. (Or, buy cheap at Amazon.com)
Free on-line aviation calculations.
Flight Log: From NavPlan site (link above)
KCMI Airport Chart:
Default X-Plane C-172 panel:
The Flight
Departure - Panel Setup:
HDG bug set to - 040 (runway heading).
NAV #1 set to SPI VOR (112.7)
SPI VOR OBS (course) set to 100° (radial outbound from SPI VOR for V50 Airway - see chart).
NAV #2 set to AXC VOR (117.2) your next navaid on V50.
AXC VOR OBS set to 096 (inbound course to AXC), the reciprocal of the 276° radial shown on the chart (you are flying east - inbound to the AXC VOR).
After Takeoff:
Note takeoff time! ____:____.
Fly runway heading until leaving 500' AGL (Above Ground Level), then turn right to heading 140 to join V50 (100° radial from SPI VOR).
When established on heading 140, select the autopilot NAV mode. The AP will now intercept and track the SPI 100° radial.
Map showing takeoff from KSPI and turn to intercept V50.
Turn angle to intercept on course radial depends on distance to intercept.
Normal is 45-30 degrees.
Cruise:
When level at cruise altitude, set power to cruise setting in accordance with your aircraft POH.
When halfway between SPI VOR and AXC VOR, select AXC (117.2) on NAV #1 for navigation to AXC.
Preferred method is to use DME (Distance Measuring Equipment) IF total distance between SPI and AXC is 38 nm, then half is 19nm.
IF no DME, then use elapsed time. NM (= nautical miles) / GS (= groundspeed).
Formula for time: (NM / GS X 60 = time)
19(nm) / 120(gs) X 60 = 9.5 minutes +
"+" Allow an extra minute or so because you were climbing; depending on cruise altitude and speed difference from that at cruise.
OR, use a crossing bearing. If one exists (below).
Don't forget to adjust your course to 096° (inbound course to AXC).
Turning The Corner At AXC VOR:
If DME equipped turn to the outbound heading prior to reaching the VOR. Do this so as to roll out close to your desired outbound course.
The distance depends on your ground speed. Rule of thumb is 10% of your speed (180 kts = about 1.5nm for a 90° turn).
IF no DME, then you must wait for the "TO/FROM" flag to reverse and show "FR" to know you have passed AXC VOR.
To be ready for this: Set NAV #2 to CMI (110.0) and set 054 on the OBS (V251 to CMI). When the needle starts to move you know you are getting close to the AXC VOR because the radial from CMI VOR should pass near the AXC VOR.
At this time switch to HDG mode on the AP. When the VOR indicator changes to "FR", turn your HDG bug to 030 and change your CRS selector to 053 (radial for V251). When steady on 030 HDG select NAV mode on the AP. It will now intercept and track the 053 radial out from AXC VOR (V251).
Note your time passing AXC VOR! ___:____!
Changeover Point Between AXC VOR and CMI VOR:
Use the same procedure as above, except the distance is now a total of 32nm, so half is 16nm and your speed should be a bit faster as you are no longer climbing, but may be descending.
Groundspeed = ???
Therefore minutes to fly from AXC before changeover is: ???
Start Descent - When?:
The weather reported at KCMI is 3500' broken and 3.5 SM (statute miles) visibility. Surface visibility is given in SM.
Airport elevation is 755' (as noted in the brown diamond around KCMI on the enroute chart (shown earlier).
Your present altitude is _______'.
Minimum altitude on V251 is 2500' (shown earlier).
Desire: descend to VFR below the clouds in time to make a normal landing in VFR conditions on runway 32R at KCMI.
Descent rate: Normal.
For a non-pressurized aircraft = 500 fpm
For a pressurized aircraft = 1000 - 1500 fpm
For a jet aircraft = 1500 - 3000 fpm
Example: When to start descent? (CMI VOR on the field).
For non-pressurized aircraft:
From 5000' (cruise altitude) - 755' (field elevation) = 4245' / 500 fpm = 8.5 minutes + 1 for speed reduction = 9.5 to 10 minutes out from CMI.
Remember to enrich the mixture as you descend.
When you break out of the clouds be looking for the airport. When spotted, check your airport diagram and proceed to land on runway 32R.
Trick: Even when landing VFR put your course selector on the runway heading to help align yourself with the proper runway (especially at airports with more than one runway).
Notes: Things to try:
- Try flying all or part of the trip using the HDG bug to remain on course rather than the AP NAV mode.
- Try adding a crosswind.
- Lower the weather with each flight until successful completion with 3000'/3.5 SM vis.
- Try a faster airplane.
- Try an airplane with an HSI or VOR (whichever one not used previously).
That's it; we hope you enjoyed your flight!
Please see the addenda at the end of this document for more information.
Epoch Alaska Air
http://www.unex-planedapps.com
Optional Scenery Enhancements:
X-Plane 9: KSPI (Springfield) and KCMI (Champaign)
X-Plane 10: KSPI (Springfield) and KCMI (Champaign)
FSX
Springfield/Abraham Lincoln Capital Airport (KSPI)
FS2004 KSPI (Springfield) and KCMI (Champaign)
Basic Instrument Flight
The HSI
The horizontal situation indicator (commonly called the HSI) is an aircraft instrument normally mounted below the artificial horizon in place of a conventional heading indicator. It combines a heading indicator with a VOR/ILS display, reducing pilot workload by lessening the number of elements in the pilot's instrument scan to the six basic flight instruments.
On the HSI, the airplane is represented by a schematic figure in the center of the instrument - the VOR/ILS display is shown in relation to this figure. The heading indicator is usually slaved to a remote compass, and the HSI is frequently interconnected with an autopilot capable of executing an approach by following the localizer and glide slope.
When an HSI is tuned to a VOR station, left and right always mean left and right and TO/FROM is indicated by a simple triangular arrowhead pointing to the VOR. If the arrowhead points to the same side as the course selector arrow, it means TO, and if it points behind to the side opposite the course selector, it means FROM. The HSI illustrated here is a type designed for smaller airplanes, and is the size of a standard 3-1/4 inch instrument.
Additional Video Information
A video about the HSI:
Using a VOR - animation video:
Navigation using a VOR:
A video about the KAP140 autopilot:
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