Cessna 172P - Page 48

SECTION
3
EMER,GENCY PN,OCEDURES
CESSNA
MODEL
172P
RPM
taxi.
Under
these conditions,
the light
will
go
out a,t
higher RPM.
The
ma,ster Êwitch need not
bo
recycled
since
arr over-voltage
condition
has
not occurred
to
de-activate
the
alternator
system.
If the over-voltage sensor
should sbut
down
tbe alternator,
or if the
alternator
output is low, a
discharge rate
will
be shown
on
the
ammeter
followed by illumination
of the low-voltage waming ligbt.
Sinco this may
be a
"nuisance"
trip-out,
a¡r attempt should bo made to reactivate
the
alternator
system.
1o
do
this, tu¡n the avionios
power
switoh off,
oheok that
tho alternator
oir<¡uit
breaker is ln, tben turn both sides of the
master
switch off and
then on again.
If the
problem
no longer
exists, no¡rnal
alternator
charging will
resume and the low-voltage lightwill
go
off. The
avionios
power
switch
may then be turned back on. If
the
light illuminates
again, a
malfunction
is oonfirrned. In this
event, the flight
should be
terrninated and/or
the
current drain on the
battery
minimized
because
the
battory
can supply
the electrical system
for only a lirnited
period
of
time.
Battery
por¡uer
must
be congerved
for later
operation
of the
wing
flaps a,nd,
if
the
emergency
occurs at
night, for
possible
use of the landing lights
during
landing.
3-18
30 May
1980