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Instrument Navigation. Chapter 2, Section C. VOR Navigation. Ground Based Transmitter 360 Radials Aligned with magnetic north Directional Line of sight. VOR Ground Facility. Ground Facilities - VOR. Operate in 108.0 - 117.95 MHz Band Standard Service Volumes (SSV)
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Instrument Navigation Chapter 2, Section C
VOR Navigation • Ground Based Transmitter • 360 Radials • Aligned with magnetic north • Directional • Line of sight
Ground Facilities - VOR • Operate in 108.0 - 117.95 MHz Band • Standard Service Volumes (SSV) • High Altitude(HVOR) - 200 watts, up to 130 nm, used for airways • Low Altitude(LVOR) - about 100 watts, up to 40 nm, used for airways • Terminal(TVOR) - 50 watts, 25 nm, used for approaches
VOR Receiver Checks • VOT • 180o TO, 360o FROM; +/- 4o • VOR Ground Checkpoint • Indicated radial; +/- 4o • VOR Airborne Checkpoint • Indicated radial; +/- 6o • Centerline of airway; +/- 6o • Dual VOR Check • Within 4o
Using the VOR • CDI • To-From Indicator • Intercepting a radial • Tracking • wind correction • Station passage • cone of confusion • Reverse sensing
Rotating Course Card TO/FROM Omni Bearing Selector Course Deviation Indicator
Using the VOR • Basic VOR Indicator • each dot on CDI is 2o • full scale deflection is 10o • 1 deg in 60 nm is 1 nm • OBS • Horizontal Situation Indicator HSI • incorporates HI, CDI, Glideslope • makes easier to scan • not reverse sensing except for using on BC
VOR Time & Distance Calculations • 90 deg Method (no wind) • Time to station=Time(sec)/bearingchange
Time to station (min) • Established inbound on a radial rotate the obs 10o to the left, turn the aircraft 10o to the right • Note the time and maintain heading until the cdi centers • 60 x Min flown between bearing change Degrees of bearing change
Distance To station (NM) • TAS X Min. flown between bearing change • Degrees of bearing change
Isosceles Triangle B 5 minutes 5 minutes C A
ADF Navigation • Ground based transmitter • Low/medium frequency (AM) • Non-directional beacon (NDB) • Not line of sight • No receiver checks • No flags - listen to Morse code
Operational Considerations • NDB • Compass locator (LOM) - 25 watts, 15 NM • MH - less than 50 watts, 25 NM • H - 50 to 1999 watts, up to 50 NM • HH - 2,000 watts or more, 75 NM
Using the ADF (fixed card) • Magnetic heading + relative bearing = magnetic bearing • Intercepting a bearing • Tracking • wind correction • to the station • from the station • Time and distance to a station • Station passage
DME • Ground based - VOR/DME, VORTAC, ILS/DME, LOC/DME • Interrogation and response • rate * time = distance • Uses slant distance - 1 NM away for each 1000’ elevation
Area Navigation • VOR/DME, VORTAC based • Phantom VORs • INS • Self Contained • LORAN
Radio Magnetic Indicator RMI • HI, 1 or 2 pointers for the different stations • Pointers show the bearing to the station without mental calculations • Tail of the VOR pointer is the radial you are on
Global Positioning System(GPS • Describe how it works. • A fog horn blows on the hour, … speed of sound is 550 ft/s. • Same for GPS except using speed of light. • Accuracy within 300 meters 99.99% of time • Vertical accuracy is not great. • Accuracy can be improved by DGPS
Global Positioning System(GPS) • RAIM • continuously monitors signals received for validity • required for IFR GPS
Global Positioning System(GPS) • Two Main types of IFR GPS • enroute approved • approach approved • database must be updated frequently • database contains info about airports, intersections, VOR, NDB, etc • Lack of Standardization among manufacturers
GPS Approaches • Generally has a LCD or LED CDI • “fly to the bars” • when navigating 30 miles away • 1 dot is 1 nm, 5 nm full scale deflection • when closer • ramps to 1 nm full scale deflection • as you fly the approach • ramps down to 0.3 nm full scale deflection