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Navigation Aids(AIR)

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Automatic Direction Finder (ADF) A low or medium frequency radio beacon

transmits non-directional signals whereby thepilot of an aircraft properly equipped candetermine bearings and "home in" on the station.

The frequency range for NDBs is between 190and 1750 kHz

Signals follow the curvature of the earth, so theycan be received at much greater distances at

lower altitudes, a major advantage over VOR. Operates by using two types of antennas, theLOOP and SENSE antenna.

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Advantages and Limitations Long range. Can use medium

frequency ground

station. Ideal navigation aid

for small aircrafts

Light weight and lowpower.

Mountain or Cliffs Shorelines Electrical storm Bank Error

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VHF Omni-directional Range(VOR)

VORs operate within the 108.0 to 117.95 MHzfrequency band.

VORs broadcast a VHF radio composite signal

including the station's morse code identifier, anddata that allows the airborne receivingequipment to derive the magnetic bearing fromthe station to the aircraft

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Advantages and Disadvantages Great Accuracy Signal Provides

To/From bearing to

the beacon. Free from

precipitation staticand annoyinginterference by other weather conditions.

Most expensive tobuild and maintain

Needs extensive

networks due to lackof range

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Tactical Air Navigation (TACAN) It operates in the frequency band 960-1215

MHz. Navigation system used by military aircraft.

Capable of showing the azimuth representationand the distance of enemy planes Military version of VOR/DME systems Increase by 9 folds in terms of accuracy than

VOR Same Specifications as Civil DME

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Distance Measuring Equipment(DME)

Paired pulses at a specific spacing are sent outfrom the aircraft (this is the interrogation) andare received at the ground station.

The time required for the round trip of this signalexchange is measured in the airborne DME unitand is translated into distance (nautical miles)from the aircraft to the ground station.

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Instrument Landing System (ILS)

Guidanceinformation: localizer, glide slope;

Range information: marker beacon, DME; Visual information:

approach lights,

touchdown andcenterline lights,runway lights

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Microwave Landing System (MLS) The MLS provides precision navigation guidance

for exact alignment and descent of aircraft onapproach to a runway.

Capabilities Approach Azimuth Back Azimuth Approach elevation Range Data communication

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TCAS

a computerized avionics device which isdesigned to reduce the danger of mid-air

collisions between aircraft. It monitors the airspace around an aircraft,

independent of air traffic control.

warns pilots of the presence of other aircraft which may present a threat of mid-air collision.