Cessna Hawk XP - Excessive Rate of Charge; Insufficient Rate of Charge

SECTION 3
EMERGENCY PROCEDURES
CESSNA
MODEL R172K
A damaged or improperly adjusted voltage regulator can also cause
malfunctions. Problems of this nature constitute an electrical emer-
gency and should be dealt with immediately. Electrical power mal-
functions usually fall into two categories: excessive rate of charge
and insufficient rate of charge. The following paragraphs describe the
recommended remedy for each situation.
EXCESSIVE RATE OF CHARGE
After engine starting and heavy electrical usage at low engine
speeds (such as extended taxiing) the battery condition will be low
enough to accept above normal charging during the initial part of a
flight. However, after thirty minutes of cruising flight, the ammeter
should be indicating less than two needle widths of charging current.
If the charging rate were to remain above this value on a long flight,
the battery would overheat and evaporate the electrolyte at an exces-
sive rate. Electronic components in the electrical system could be ad-
versely affected by higher than normal voltage if a faulty voltage regu-
lator setting is causing the overcharging. To preclude these possibili-
ties, an over-voltage sensor will automatically shut down the alternator
and the over-voltage warning light will illuminate if the charge voltage
reaches approximately 16 volts. Assuming that the malfunction was
only momentary, an attempt should be made to reactivate the alternator
system. To do this, turn both sides of the master switch off and then on
again. If the problem no longer exists, normal alternator charging will
resume and the warning light will go off . If the light comes on again, a
malfunction is confirmed. In this event, the flight should be terminated
and/ or the current drain on the battery minimized because the battery
can supply the electrical system for only a limited period of time. If
the emergency occurs at night, power must be conserved for later use
of landing lights and flaps during landing.
INSUFFICIENT RATE OF CHARGE
If the ammeter indicates a continuous discharge rate in flight , the
alternator is not supplying power to the system and should be shut
down since the alternator field circuit may be placing an unnecessary
load on the system. All nonessential equipment should be turned off
and the flight terminated as soon as practical.
3-16
CESSNA
MODEL R172K
SECTION 4
NORMAL PROCEDURES
SECTION 4
NORMAL PROCEDURES
TABLE OF CONTENTS
....
. ...
Introduction · · · · · · '.
Speeds For Normal Operation
CHECKLIST PROCEDURES
Preflight Inspection
Cabin · · · ·
Empennage · : . · · · · ·
Right Wing, Tra1lmg Edge
Right Wing .
Nose
Left Wing · · · · · · ·
Left Wing, Leading Edge
Left Wing, Trailing Edge
Before Starting Engine
Starting Engine
Before Takeoff . · · ·
Takeoff · · · · · · ·
Normal Takeoff
Short Field Takeoff
Enroute Climb · · · ·
Normal Climb · · · · · .' ·
Maximum Performance Climb
Cruise
Descent
Before Landing
Landing · · · · · ·
Normal Landing
Short Field Landing
Balked Landing
After Landing · ·
Securing Airplane
Starting Engine
AMPLIFIED p~OCEDURES
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