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Pilot's Handbook of Aeronautical Knowledge

Radio Navigation

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Pilot's Handbook of Aeronautical Knowledge



Table of Contents

Chapter 1, Introduction To Flying
Chapter 2, Aircraft Structure
Chapter 3, Principles of Flight
Chapter 4, Aerodynamics of Flight
Chapter 5, Flight Controls
Chapter 6, Aircraft Systems
Chapter 7, Flight Instruments
Chapter 8, Flight Manuals and Other Documents
Chapter 9, Weight and Balance
Chapter 10, Aircraft Performance
Chapter 11, Weather Theory
Chapter 12, Aviation Weather Services
Chapter 13, Airport Operation
Chapter 14, Airspace
Chapter 15, Navigation
Chapter 16, Aeromedical Factors
Chapter 17, Aeronautical Decision Making




ADF terms.
Figure 15-37. ADF terms.

Keep in mind that the needle of fixed azimuth points to the
station in relation to the nose of the aircraft. If the needle is
deflected 30° to the left for a relative bearing of 330°, this
means that the station is located 30° left. If the aircraft is
turned left 30°, the needle moves to the right 30° and indicates
a relative bearing of 0°, or the aircraft is pointing toward
the station. If the pilot continues flight toward the station
keeping the needle on 0°, the procedure is called homing to
the station. If a crosswind exists, the ADF needle continues to
drift away from zero. To keep the needle on zero, the aircraft
must be turned slightly resulting in a curved flightpath to the
station. Homing to the station is a common procedure, but
results in drifting downwind, thus lengthening the distance
to the station.

Tracking to the station requires correcting for wind drift and
results in maintaining flight along a straight track or bearing
to the station. When the wind drift correction is established,
the ADF needle indicates the amount of correction to the
right or left. For instance, if the magnetic bearing to the
station is 340°, a correction for a left crosswind would
result in a magnetic heading of 330°, and the ADF needle
would indicate 10° to the right or a relative bearing of 010°.
[Figure 15-38]

When tracking away from the station, wind corrections are
made similar to tracking to the station, but the ADF needle
points toward the tail of the aircraft or the 180° position on
the azimuth dial. Attempting to keep the ADF needle on
the 180° position during winds results in the aircraft flying
a curved flight leading further and further from the desired
track. To correct for wind when tracking outbound, correction
should be made in the direction opposite of that in which the
needle is pointing.

ADF tracking.
Figure 15-38. ADF tracking.

Although the ADF is not as popular as the VOR for radio
navigation, with proper precautions and intelligent use, the
ADF can be a valuable aid to navigation.