Contents:

1. Ground Equipment
   

2. Airborn Equipment

3. Navigation Procedures

4. Checking VOR Accuracy

5. Horizontal Situation Indicator (HSI)

6. Distance Measuring Equipment (DME)

1. Ground Equipment

• VOR (Very high frequency Omnidirectional Range)

• The VOR system:

• Is used for course guidance and aircraft positioning

• Consists of over 1,000 installations

• Enables cross-country navigation

• If your aircraft has distance measuring equipment (DME), you can use VOR/DME and VORTAC to obtain distance information

• VOR/DME facilities combine course guidance and distance measuring equipment

• VORTAC facility is a collocated VOR and a TACAN. Civil aviation uses the portion of the TACAN that provides distance information

• VOR Reception

• The radio signals transmitted by a VOR operate in the very high frequency (VHF) range

• They are limited to line of sight reception

• When obstacles reduce your VOR reception range below the standard values published in the Aeronautical Information Manual, the affected route and usable range appears in the A/FD

• VOR Broadcast Pattern

• VOR radio means (radials) are:

• Transmitted in all directions

• Accurate to one degree, so only 360 of the radials are used for navigation

• Numbered in one-degree increments clockwise from magnetic north

• VOR Chart Depiction

• VOR Classes

2. Airborne Equipment

• Airborne Equipment Components

• VOR airborne equipments consists of:

• The VOR antenna, which receives radio signals from a VOR station and reays them to the VOR receiver

• The VOR receiver, which processes ground signals and sends course information to the VOR indicator

• The VOR indicator, which provides course guidance and displays aircraft location in relation to the VOR station

• VOR Indicator Components:

• The course deviation indicator (CDI), the needle of which, when centered, indicates that you are on course. If the needle swings to either side, you are off course

• The TO-FROM indicator, which shows whether the course will take you to or from the VOR station

• The omnibearing selector (OBS), which enables you to choose a course or radial by rotating the azimuth dial on the VOR indicator. You identify a radial by setting the azimuth dial next to the course index and centering the CDI needle with a FROM indication

• Additional components are:

• The azimuth dial, which is a compass rose calibrated in 5-degree increments

• The course index, which is the reference point on the VOR indicator that aligns with the azimuth dial to identify a VOR course or radial

• The reciprocal course index, which is the reference point on the VOR indicator opposite the course index that aligns with the azimuth dial to identify the reciprocal of a VOR course or radial
  

3. Navigation Procedure

• Relying on VOR

• Before relying on VOR:

• Tune and identify the transmitting station

• Verify that the frequency is correct and that the station is working

• Monitor the VOR station identifier on many receivers by selecting the identification (IDENT) feature and increase the volume

• When a station is shut down for maintenance, it might either transmit a TEST signal in Morse code or transmit no identifier at all

• If you don't hear the Morse code identifier or voice identification, you might not be receiving a reliable navigation signal

• Radial from a VOR

• To determine radial from a VOR station with a VOR indicator:

• Tune in the station

• Turn the OBS knot until the CDI needl centers with a FROM indication

• Read the resulting radial next to the course index on the top of the VOR indicator

• Course to a VOR Station

• To determine a course to a station:

• Tune in the station

• Turn the OBS knot until the CDI needl centers with a TO indication

• Turn the aircraft to the heading displayed on the VOR indicator and, assuming there is no crosswind, fly directly on course to the station

• A Chart Course to a VOR

• To determin the course to a VOR station from a location on a secional chart

• Plot the course

• Note where the course intersects the VOR compass rose

• Your course to the VOR is reciprocal of the value shown on the compass rose intersection

• VOR indication and Aircraft Heading

• A VOR airborne system doesn't account for your aircraft's heading; it only senses direction from the station

• Interpreting a CDI

• Reverse Sensing

• Occurs when your VOR indicator is set to the reciprocal of your desired course

• Off Indication

• When you approach a VOR station, the TO indication might be replaced by an OFF flag, a NAV indication, or a barberpole, or you might have no indication at all

• When your VOR indicator provides one of these displays, it can mean:

• You are directly over the station

• You are 90 degrees on the either side of the course

• The VOR signal is unreliable

• Tracking

• Tracking is maintaining a course by keeping the CDI needle centered

• In a crosswind, you use bracketing to make course corrections:

• Maintaining and regaining your course by using a series of corrections is called bracketing

• Intercepting a Course

• Might need to track to the station on a difference course instead of flying direct

• Depart from the radial you are currently tracking

• Set up an intercept angle for the intercept course to another radial

• Track the new inbound course to the station

• Intercept angles can range from approximately 20 degrees to 90 degrees, depending on the distance from the station and the course

• Cross Checking Your Position

• Determining your position by cross checking a second VOR station

• For the most accurate intersecting lines of position, select radials that are nearly perpendicular to each other
  

• VOR Orientation

• Determining position with respect to a VOR facility is called VOR orientation

4. Checking VOR Accuracy

• Checking VOR Accuracy

• Determine the accuracy of VOR equipment by using either ground or airborne VOR checkpoints

• On the ground:

• Taxi your aircraft to a specific point on the airport designated in the VOR Receiver. Check section of the Airport/Facility Directory

• Center your CDI needle and compare your VOR course indication to the published radial for that checkpoint

• Airbone:

• Use the sectional chart to locate a terrain feature under the airway, at least 20 miles

• Maneuver over the point, turn the OBS knob to center the CDI needle, and note the course

• VOR Test Facilities

• VOTs enable you to make precise VOR accuracy checks, regardless of your position in relation to the facility

• Obtain the frequency from the A/FD, and then tune your VOR receiver and identify the VOT signal

• Set a course of either 0 degree or 180 degrees. A course setting of 0 degree should center the CDI with a FROM indication. A course setting of 180 degrees should center the CDI with a TO indication

• If the CDI needle does not center, determine the magnitude of the error by rotating the OBS until the needl centers

• The new course should be +- 4 degrees for both the 0 degree and 180 degrees test courses

5. Horizontal Situation Indicator (HSI)

6. Distance Measuring Equipment (DME)

• The DME transceiver transmits an interrogation signal; the ground station then trasmits a reply to the aircraft

• The equipment measures the round trip time of this exchange, computes the distance in nautical miles, and displays it in the cockpit

• Up to 199 nautical miles range from a station, depending on altitude and line-of-sight restrictions