ch _ 6 VOR Presentation

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ch _ 6 VOR Presentation Powered By Docstoc
					  VHF Omni directional Range
• The VOR (VHF Omni directional Range)
  navigation system, was probably the
  most significant aviation invention. With
  it, a pilot can simply, accurately, and
  without ambiguity navigate from Point A
  to Point B.
   It is a radio aid that provide, with
   interaction of airborne equipment,
   information about
1. Azimuth
2. Course
3. To-From to the VOR Station
       AZIMUTH in VOR:
is a clockwise angle between magnetic
north and line connecting the VOR and the
aircraft. The indication is displayed on an
―Omni Bearing Indicator‖ in the aircraft.
             The COURSE:
 is the information whether aircraft is flying to the
 left or right of, or exactly on the pre-selected
 course line. The course information is displayed
 on a "Flight Path Deviation Indicator".

TO-FROM indication:
 tells the pilot whether an aircraft is approaching
 to or moving away from VOR stations.
Course and To-From indication
       Operating Frequency
• It operate in VHF band range from
 Basic Principle of operation
The VOR facility transmits two 30Hz
signals at the same time.
One 30Hz signal is constant in all the
directions (constant phase) Called
Reference signal.
while the other 30Hz is rotated about the
station (phase change/varies through out
the 360 degree) called variable signal.
             Basic Principle
 The airborne equipment receives both
  signals, looks (electronically) at the phase
  difference between the two signals, and
  interprets the result as a radial from the
  The variable signal is initially set such that
  at magnetic north both the signals are
  exactly in phase
• Station ID Code also transmitted
• Here is an example to explain the working
  of VOR. Imagine a wheel of cycle with 360
  spokes at one degree azimuth spacing,
  with VOR station being the hub. The
  spokes are numbered clockwise from one
  to 360 and each spokes or radial
  represent a magnetic bearing from/to the
  VOR beacon.
       VOR Airborne Receiver /
        Omni-Bearing Indicator
• Course Selector is used in conjunction
  with left – right and To – From indicator to
  display VOR information . This type of
  display is called ―Omni Bearing Indicator‖.
VOR Airborne Receiver /
 Omni-Bearing Indicator
The VOR display has four basic elements:
• Rotating Course Card, calibrated from 0
  to 360°, which indicates the VOR bearing
  chosen as the reference to fly
• Omni Bearing Selector: The Omni
  Bearing Selector, or OBS knob, used to
  manually rotate the course card to select
  the desired bearing in relation to VOR
   The CDI, or Course Deviation
• The CDI indicates the position of aircraft relative to the
  selected bearing and it will move to the left or right
  according to relative position to the bearing selected, the
  needle moves across a scale of dots, each representing
  certain degree of deviation from selected course.
• The needle will be in the center when aircraft is on
• This needle swings left or right indicating the
  direction to turn to return to course. When the
  needle is to the left, turn left and when the
  needle is to the right, turn right, When centered,
  the aircraft is on course.
     The TO-FROM indicator.
• This arrow will point up, or towards the nose of
  the aircraft, when flying TO the VOR station. The
  arrow reverses direction, points downward,
  when flying away FROM the VOR station.
• A red flag replaces these TO-FROM arrows
  when the VOR is beyond reception range
   the VOR receiver is turned off.
   the aircraft is passing over the VOR station.
 This aircraft is north of the Omni station, flying on the 345° radial away
FROM the station. The left-right needle shows the aircraft on course and

  the FROM flag is present, pointing down, toward the station behind.
This aircraft is south of the Omni station. Its magnetic
                     course is 345°.
• The aircraft isn't on the 345° radial
  because that radial extends from the Omni
  to the northwest
• The aircraft is actually on the reciprocal
  radial, the radial pointing towards the
  plane. That reciprocal radial is 165°, away
  from the station like all radials.
Wandering off course?
The needle is centered, my flying is
               OFF" flag
• The VOR indicator is smart enough to
  know when a usable signal has not been
  received and displays an "OFF" flag, a red
  and white barber-pole striped flag in the
• The OFF flag also displays if the Nav
  receiver is tuned to the wrong frequency
  or, blush, if it's properly tuned but you
  neglected to turn on the power switch
     General Types of VOR
1. DVOR (Doppler)
2. CVOR (Conventional)
Where am I?
• This illustration shows the confusion that can
  result, yes, that the VOR indicator can actually
  provide wrong information if the OBS isn't set
• The aircraft is south of the Omni, on the 165°
  radial. It is flying northwest. Observe the DG.
  The aircraft is heading 345° as desired. But the
  OBS was improperly set to 165° and the VOR is
  falsely informing the pilot, with a nicely centered
  needle, that he/she is flying away FROM the
  Omni. The aircraft, of course, is flying TO the

The HSI may display bearing and distance to a navigation aid,
  magnetic heading, track/ track deviation and course/course
• The centre portion of the course pointer needle
  moves to indicate deviation from selected
  course. A series of "dots" provides a linear
  indication of how far the aircraft is "off course."
  In VOR use, each dot represents 5 degrees;
  when being used to fly the localizer, it shows 1
  1/4 degrees per dot; for RNAV "APPR" mode,
  0.625 nm per dot; and for RNAV "Enroute" mode
  it indicates 1.25 nm per dot. An "on course"
  condition is indicated when the course pointer,
  the course deviation bar, and the course
  reciprocal are all "in line."
DVOR (Doppler)

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