Grnd-52 Theory of Flight 5 Navigation Instruments

What are navaids used for?

Ground based radio direction finding equipment is used to indicate the aircraft position from a ground station

Three types of independent navaids

ADF, VOR, TACAN

Two types of combined navaids

VOR/DME, VORTAC

ADF (automatic direction finding)

Oldest system in use.

LF-MF NDB (190-1750kHz)

Not line-of-site, provides continuous magnetic bearing information with long range reception at low altitudes

VOR (VHF omnidirectional range)

Primary basis for civil airways in North America.

line-of-site operation (108.1 - 117.95 MHz) provides continuous magnetic bearing information with shorter reception range (50 - 150 nm), altitude dependent

TACAN

UHF line of sight operation provides continuous magnetic bearing information, may be oriented to true or grid north, altitude dependent

DME provides slant range distance up to 200 nm

Air to ground interrogation: 1025-1150 MHz

Ground to air reply: 962-1024 MHz, 1151-1213MHz

VORTAC

VOR beacon and TACAN beacon mounted coaxially

VOR/DME

A normal VOR beacon that provides bearing only with the ranging element (DME) of a TACAN system.

Bearing

When the point is read against compass card

Radial

When the tail is read against the compass card

Relative bearing

When the point is read against a fixed index

Position Line

When a bearing is plotted or imagined on a map

Three RMI position fix methods

Cross fix of position lines

Position lines with distance information

Station passage