Cessna 152 - Page 38

SECTION3
EMERGENCY
PROCEDURES
CESSNA
MODEL
152
the
ignition
switch
unless
extreme
roughness
dictates
the
use
of
a
single
ignition
position.
MAGNETO
MALFUNCTION
A
sudden
engine
roughness
or
misfiring
is
usually
evidence
of
magneto
problems.
Switching
from
BOTH
to
either
Lor
R
ignition
switch
position
will
identify
which
magneto
is
malfunctioning.
Select
different
power
settings
and
enrichen
the
mixture
to
determine
if
continued
operation
on
BOTH
magnetos
is
practicable.
If
not,
switch
to
the
good
magneto
and
proceed
to
the
nearest.
airport
for
repairs.
LOW OIL PRESSURE
If
low
oil
pressure
is
accompanied
by
normal
oil
temperature,
there
is
a
possibility
the
oil
pressure
gage
or
relief
valve
is
malfunctioning.
A
leak
in
the
line
to
the
gage
is
not
necessarily
cause
for
an
immediate
precautionary
landing
because
an
orifice
in
this
line
will
prevent
a
sudden
loss
of
oil
from
the
engine
sump.
However,
a
landing
at
the
nearest
airport
would
be
advisable
to
inspect
the
source
of
trouble.
If
a
total
loss
of
oil
pressure
is
accompanied
by
a
rise
in
oil
temperature,
there
is
good
reason
to
suspect
an
engine
failure
is
imminent.
Reduce
engine
power
immediately
and
select
a
suitable
forced
landing
field.
Use
only
the
minimum
power
required
to
reach
the
desired
touchdown
spot.
ELECTRICAL POWER SUPPLY
SYSTEM
MALFUNCTIONS
Malfunctions
in
the
electrical
power
supply
system
can
be
detected
by
periodic
monitoring
of
the
ammeter
and
low-voltage
warning
light;
however,
the
cause
of
these
malfunctions
is
usually
difficult
to
determine.
A
broken
alternator
drive
belt
or
wiring
is
most
likely
the
cause
of
alternator
failures,
although
other
factors
could
cause
the
problem.
A
damaged
oi."
improperly
adjusted
alternator
control
unit
can
also
cause
malfunctions.
Problems
of
this
nature
constitute
an
electrical
emergency
and
should
be
dealt
with
immediately.
Electrical
power
malfunctions
usually
fall
into
two
categories:
excessive
rate
of
charge
and
insufficient
rate
of
charge.
The
paragraphs
below
describe
the
recommended
remedy
for
each
situation.
EXCESSIVE RATE OF
CHARGE
After
engine
starting
and
heavy
electrical
usage
at
low
engine
speeds
3-14
1
July
1978