VOR Navigation Flashcards
VOR definition
►VHF Omni-directional Range
►Primary navigational system in the U.S.
•GPS will render it obsolete just like the VOR did to the ADF
VOR frequencies
►VOR: Freq. Range 108.00 MHz-117.95 MHz
►Uses even tenths for VOR
► LOCALIZER: Between 108.00 MHz and 112.00 MHz
–use odd tenths for localizer
Identification
►Morse Code:
•3 letter ident every 10 seconds
►Some broadcast the name then the morse code
►Some broadcast HIWAS and morse code
NAVAID Service volumes
Nav radio aids which provide positive course guidance have a designated standard service volume
The SSV defines the reception limits of NAVAIDS
VOR service volumes
Terminal (T): 25 nm- 1000 ft to 12000 ft
Low (L): 40 nm- 1000 ft to 18000 ft
High (H): 40 nm- 1000 ft to 14500 ft
100 nm-14500 ft to 18000 ft
130 nm- 18000 ft to 45000 ft
100 nm- 45000 ft to 60000 ft
VOR service volumes MON
VOR Low (VL): 40 nm- 1000 ft to 5000 ft
70 nm- 5000 ft to 14500 ft
VOR High (VH): 40 nm- 1000 ft to 5000 ft
70 nm- 5000 ft to 14500 ft
100 nm- 14500 ft to 18000 ft
130 nm- 18000 ft to 45000 ft
100 nm- 45000 ft to 60000 ft
VOR MON
(Minimum Operational Network)
•PBN (Performance-Based Navigation) enabled by GPS is gradually replacing VOR navigation
•MON is comprised of VORs retained for use in the event of GPS outage
•VOR MON allows nearly continuous coverage across US airspace from 5,000 feet up
•MON airports within 100 NM of anywhere in the US
Range depends on
►Aircraft Altitude
►Class of Facility
►Location and Siting of Facility
►Terrain/obstructions
►Geographical location of other VORs on the same frequency
VOR theory
► Principal of electronically measuring an angle
► 2 VHF signals
1 is rotating (variable phase)
1 is all directional (reference phase)
►Receiver in a/c measures phase difference between 2 signals
►A/C VOR Receiver –gives you relative position (to or from) the station based on magnetic north
•Variation for magnetic north was determined at the time the VOR was installed
Parts of VOR receiver/indicator
►Frequency Selector
►Omnibearing Selector–0BS
–1 to 360
►Course Deviation Indicator–CDI
•Number of dots/degrees of dots
•Full Scale Deflection is 12 degrees off course
►To-From Indicator
VOR receiver check
At least every 30 days from use
►Ground
•plus or minus 4 degrees
►Flight
•plus or minus 6 degrees
•Except Dual VOR in air is still 4 degrees
►Designated ground and flight checkpoints are listed in the AFD
►Enter operational checks in aircraft logbook or reliable record
•date
•location
•error
•Pilot signature
VOT check
•The VOT transmits a signal which allows you to determine the operational status/accuracy of a VOR receiver:
On the ground
In the air
•VOT locations are published in the Airport Chart Supplement on the applicable airport page and in the VOR Receiver Checkpoints and VOR Test Facilites page
•To use the VOT service:
Tune the VOT frequency on the VOR receiver
Center the CDI with a FROM indication
With the CDI centered, the OBS should read:
0 degrees with a FROM indication
180 degrees with a TO indication
RMI points to 180
VOR advantages
►360 Courses to choose from
►Fairly accurate
►Reception not influenced by aircraft attitude or direction of flight
VOR limitations
►Line of sight reception
►Interference can occur between two VOR’s at high altitudes
►Periodic shutdowns of ground transmitter
Cone of confusion
•Where the VOR signal is ambiguous and the VOR display is unreliable.
• Flying through this airspace would cause erratic behavior of your CDI needle (Course Deviation Indicator) and of the to/from flag on the VOR displays
