Radio Navigation

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Radio Navigation
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Objectives

• Understand fundamentals of NAVAID operation
• Familiarize student with NAVAID limitations
• Build students ability to orientate themselves
  using NDB and VOR NAVAIDS
• Introduce student to intercepting and tracking
  using NDB, VOR or GPS systems.

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NDB/ADF

• Definitions
• NDB Non Directional Beacon
• Refers to the actual station of ground
• ADF Automatic Direction Finder
• Refers to instrument found in the airplane

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Types of ADFs

• Fixed Card Rotate-able Card RMI

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NDB/ADF

• More Definitions
• Relative Bearing
• Direction you want to track to the station. Shown
  by the indicator needle on the ADF.
• Magnetic Heading
• Direction your nose is pointed.
• Magnetic Bearing
• Direction flown to the station in still air. RB
  MH (/- 180 for FROM)

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Limitations

• Compass Locator
• Under 25 watts/15 miles
• MH
• Under 50 watts/25 miles
• H
• 50 1999 watts/50 miles
• HH
• 2000 watts/75 miles

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Limitations

• Twilight Error
• radio waves can be reflected back by the
  ionosphere can cause fluctuations 30-60 nautical
  miles from the transmitter, especially just
  before sunrise and just after sunset (more common
  on frequencies above 350 KHz)
• Terrain Error
• high terrain like mountains and cliffs can
  reflect radio waves, giving erroneous readings
  magnetic deposits can also cause erroneous
  readings
• Electrical Error
• electrical storms, and sometimes also electrical
  interference (from a ground-based source or from
  a source within the aircraft) can cause the ADF
  needle to deflect towards the electrical source
• Shoreline Error
• low-frequency radio waves will refract or bend
  near a shoreline, especially if they are close to
  parallel to it
• Bank Error
• when the aircraft is banked, the needle reading
  will be offset

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Using the NDB

• Orientation
• Needle will always point directly at the station
• If you simply follow the needle instead of
  tracking, you are homing, and you are not
  correcting for wind

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Tracking

• Follow Steps
• Parallel Course
• Visualize ADF Needle
• on your heading indicator
• Intercept
• Double needle distance, Move towards the head
  regardless of tracking to of from the station
• To the station, head should rise to heading
• From the station, tail should fall to heading
• Tims Air Navigation Page
• http//www.visi.com/mim/nav/

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Time and Distance to Station

• Formula Method
• Turn to place station 90 degrees form aircraft
  heading and measure time it takes to travel to a
  new radial.
• Time to station Time to station (minutes) X TAS
  Time for bearing change (minutes) X
  KTAS/Degrees of bearing change.
• Example.
• It takes you 6 minutes to travel 10 Degrees
• Multiply 6 minutes by 60 (360)
• Divide by number of degrees (10)
• Answer 360/10 36 minutes to the station.

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Time and Distance Examples

• Constant Heading Method
• Amount of time it takes for relative bearing to
  double is the amount of time to station.
• i.e. ADF needle moves form a relative baring of
  045 degrees to 090 Degrees in 5 minutes, time to
  station is 5 minutes
• Isosceles Triangle method
• Turn 10 degrees to the side of your course and
  twist course selector the same amount in the
  opposite direction
• Time to station is the same as the time it takes
  for your CDI to center (assuming no wind)

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VOR NavigationVery High Frequency
Omnidirectional Range
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VOR Limitations
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VOR Limitations

• Terminal
• 12,000ft and below
• 25 miles
• Low
• Below 18,000ft
• 40 miles
• High
• Below 18, 000
• 40 miles
• 14,500 17,999ft
• (conterminous 48 States)
• 100 miles
• 18,000 FL 450
• 130 miles
• Above FL 450
• 100 miles

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VOR Navigation

• Practice makes perfect ?
• Tims Air Navigation Page
• http//www.visi.com/mim/nav/

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GPS NavigationGlobal Positioning System
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GPS Operation

• 24 satellites
• 4 for accuracy
• Times distance it takes to send and receive
  signal
• RAIM
• Receiver Autonomous Integrity System

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GPS Navigation

• Familiarize yourself with both the Bendix and
  Garmin systems
• Main Page Groups
• NAV
• Default, Map, NAVCOM, Position, Satellite status
  and VNAV
• WPT
• Airport location, runway, frequency, approach,
  arrival, departure, intersection, NDB, VOR, User
  waypoint
• AUX
• Flight Planning, utility, setup 1, setup 2
• NRST
• Airport, Intersection NDB, VOR, User waypoint,
  Center Flight service, Airspace
• Practice with the Garmin Trainer and Manual

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Questions?