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)

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

Omni Bearing Selector Course Deviation Indicator

TO/FROMRotating Course Card

Using the VORBasic 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)/bearing

change

VOR Time Distance - 900

Time to station (min)

Established inbound on a radial rotate the obs 10o to the left, turn the aircraft 10o to the rightNote 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

5 minutes

A

B

C

5 minutes

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

Rotating Card

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 timeVertical 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 ApproachesGenerally 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