Cessna 152 - Page 39

CESSNA
MODEL
152
SECTION3
EMERGENCY
PROCEDURES
(such
a,s
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
excessive
rate.
Electronic
components
in
the
electrical
system
can
be
adversely
affected
by
higher
than
normal
voltage.
The
alternator
control
unit
includes
an
over-voltage
sensor
which
normally
will
automatically
shut
down
the
alternator
if
the
charge
voltage
reaches
approximately
31.5
volts.
If
the
over-voltage
sensor
malfunctions
or
is
improperly
adjusted,
as
evidenced
by
an
excessive
rate
of
charge
shown
on
the
ammeter,
the
alternator
should
be
turned
off,
nonessential
electrical
equipment
turned
off
and
the
flight
terminated
as
soon
as
practical.
INSUFFICIENT
RATE OF CHARGE
NOTE
Illumination
of
the
low-voltage
light
and
ammeter
dis-
charge
indications
may
occur
during
low
RPM
conditions
with
an
electrical
load
on
the
system,
such
as
during
a
low
RPM
taxi.
Under
these
conditions,
the
light
will
go
out
at
higher
RPM.
The
master
switch
need
not
be
recycled
since
an
over-voltage
condition
has
not
occurred
to
de-activate
the
alternator
system.
If
the
over-voltage
sensor
should
shut
down
the
alternator,
a
discharge
rate
will
be
shown
on
the
ammeter
followed
by
illumination
of
the
low-
voltage
warning
light.
Since
this
may
be
a
"nuisance"
trip-out,
an
attempt
should
be
made
to
reactivate
the
alternator
system.
To
do
this,
turn
the
radios
off,
then
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
low-voltage
light
will
go
off.
The
radios
may
then
be
turned
back
on.
If
the
light
illuminates
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
the
landing
light
and
flaps
during
landing.
1
July
1978
3-15/(3-16
blank)