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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

The movable-card ADF allows the pilot to rotate the
aircraft's present heading to the top of the instrument so
that the head of the needle indicates MB to the station and
the tail indicates MB from the station. Figure 7-4 indicates
a heading of 045°, MB to the station of 180°, and MB from
the station of 360°.

The RMI differs from the movable-card ADF in that it
automatically rotates the azimuth card (remotely controlled
by a gyrocompass) to represent aircraft heading. The RMI
has two needles, which can be used to indicate navigation
information from either the ADF or the VOR receiver. When
a needle is being driven by the ADF, the head of the needle
indicates the MB TO the station tuned on the ADF receiver.
The tail of the needle is the bearing FROM the station. When
a needle of the RMI is driven by a VOR receiver, the needle
indicates where the aircraft is radially with respect to the
VOR station. The needle points to the bearing TO the station,
as read on the azimuth card. The tail of the needle points to
the radial of the VOR the aircraft is currently on or crossing,
Figure 7-5 indicates a heading of 005°, the MB to the station
is 005°, and the MB from the station is.185°.

Function of ADF
The ADF can be used to plot your position, track inbound
and outbound, and intercept a bearing. These procedures
are used to execute holding patterns and nonprecision
instrument approaches.

Relative bearing (RB) on a fixed-card indicator.
Figure 7-3. Relative bearing (RB) on a fixed-card indicator. Note
that the card always indicates 360°, or north. In this case, the
relative hearing to the station is 135° to the right, if the aircraft
were an a magnetic heading of 360°, then the magnetic bearing
(MB) would also be .135°.

The ADF needle points TO the station, regardless of aircraft
heading or position. The RB indicated is thus the angular
relationship between the aircraft heading and the station,
measured clockwise from the nose of the aircraft. Think of
the nose/tail and left/right needle indications, visualizing the
ADF dial in terms of the longitudinal axis of the aircraft.
When the needle points to 0°, the nose of the aircraft points
directly to the station; with the pointer on 210°, the station
is 30° to the left of the tail with the pointer on 090°, the
station is off the right wingtip. The RB alone does not indicate
aircraft position. The RB must he related to aircraft heading
in order to determine direction to or from the station.

Station Passage
When you are near the station, slight deviations from
the desired track result in large deflections of the needle.
Therefore, it is important to establish the correct drift
correction angle as soon as possible. Make small heading
corrections (not over 5°) as soon as the needle shows a
deviation from course, until it begins to rotate steadily toward
a wingtip position or shows erratic left/right oscillations. You
are abeam a station when the needle points 90° off your track.
Hold your last corrected heading constant and time station
passage when the needle shows either wingtip position or
settles at or near the 180° position. The time interval from
the first indications of station proximity to positive station
passage varies with altitude-a few seconds at low levels to
3 minutes at high altitude.

Relative bearing (RB) on a movable-card indicator.
Figure 7-4. Relative bearing (RB) on a movable-card indicator. By
placing the aircraft's magnetic heading (MH) of 045° under the
top index, the relative bearing (RB) of 135° to the right will also
be the magnetic bearing (no wind conditions) which. will take you
to the transmitting station.