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Instrument Flying Handbook
Navigation Systems
Traditional Navigation Systems

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Instrument Flying


Table of Contents

Chapter 1. Human Factors
Chapter 2. Aerodynamic Factors
Chapter 3. Flight Instruments
Chapter 4. Section I
Airplane Attitude Instrument
Using Analog Instrumentation
Chapter 4. Section II
Airplane Attitude Instrument
Using an Electronic Flight

Chapter 5. Section I
Airplane Basic
Flight Maneuvers
Using Analog Instrumentation
Chapter 5. Section II
Airplane Basic
Flight Maneuvers
Using an Electronic Flight

Chapter 6. Helicopter
Attitude Instrument Flying

Chapter 7. Navigation Systems
Chapter 8. The National
Airspace System

Chapter 9. The Air Traffic
Control System

Chapter 10. IFR Flight
Chapter 11. Emergency

VOR Transmitter (Ground Station),
Figure 7-11. VOR Transmitter (Ground Station),

MHz is in even-tenth increments to preclude any conflict
with ILS localizer frequency assignment, which uses the
odd tenths in this range.

The airborne equipment includes an antenna, a receiver, and
the indicator instrument. The receiver has a frequency knob to
select any of the frequencies between 108.0 to 117.95 MHz.
The On/Off/volume control turns on the navigation receiver
and controls the audio volume. The volume has no effect on
the operation of the receiver. You should listen to the station
identifier before relying on the instrument for navigation.

VOR indicator instruments have at least the essential
components shown in the instrument illustrated in
Figure 7-12.

The VOR indicator instrument.
The VOR indicator instrument.


Omnibearing Selector (OBS)
The desired course is selected by turning the OBS knob until
the course is aligned with the course index mark or displayed
in the course window.

Course Deviation Indicator (CDI)
The deviation indicator is composed of an instrument face
and a needle hinged to~ move laterally across the instrument
face. The needle centers when the aircraft is on the selected
radial or its reciprocal. Full needle deflection from the center
position to either side of the dial indicate the aircraft is 12°
or more off course, assuming normal needle sensitivity. The
outer edge of the center circle is 2° off course; with each dot
representing an additional! 2°.

To/FROM Indicator
The TO/FROM indicator shows whether the selected course
if intercepted and flown will take the aircraft TO or FROM
the station. it does not indicate whether the aircraft is heading
to or from the station.

Flags or Other Signal Strength Indicators
The device that indicates a usable or an unreliable signal may
be an "OFF" flag. it retracts from view when signal strength
is sufficient for reliable instrument indications. Alternately,
insufficient signal strength may be indicated by a blank or
OFF in the TO/FROM window.

The indicator instrument may also be a horizontal situation
indicator (HSI), which combines the heading indicator
and CDI. [Figure 7-13] The combination of navigation
information from VOR/Localizer (LOC) or from LORAN
or GPS, with aircraft heading information provides a visual
picture of the aircraft's location and direction. This decreases
pilot workload especially with tasks such as course intercepts.
flying a back-course approach, or holding pattern entry. (See
Chapter 3, Flight Instruments, for operational characteristics.)
[Figure 744]

A Typical Horizontal Situation Indicator (HSI).
Figure 7-13. A Typical Horizontal Situation Indicator (HSI).