Piper Cherokee Six - Page 505

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
CAUTION
Do
not
use
thread
dope,
hydrocarbon
oil
or
grease,
as
these
can
contaminate
pump
and
cause
malfunction.
c.
Use
the
following
steps
for
fitting
installation:
1.
Secure
pump
as
noted
above.
2.
The
use
of
3M-48xl/4
Teflon
tape
on
fitting
threads
is
recommended.
Insure
I
to
2
lead-in
threads
are
free
of
sealant
tape.
(Refer
to
para.
9-75,
d.
of
this
section
for
application
instructions).
3.
Insert
fittings
in
pump
ports
and
hand
tighten
firmly.
4.
Using
a
wrench,
tighten
each
fitting
from
one-half
to
two
additional
turns.
9-17b.
INSTRUMENT
AIR
SYSTEM.
(Refer
to
Figure
9-5.)
The
instrument
air
system
consists
of
a pitot
air
system
and
a
static
air
system.
Refer
to
Figure
9-5
for
system
layout.
Pitot
air
system
consists
of
a
pitot
mast
located
on
the
bottom
side
of
the
left
wing.
with
its'
related
plumbing.
Impact
air
pressure
entering
the
pitot
is
transmitted
from
the
pitot
inlet
through
hose
and
tubing
routed
in
through
the
wing
to
the
airspeed
indicator
on
the
instrument
panel.
Static
air
system
consists
of
a
static
port
located
on
the
bottom
of
the
pitot
mast.
The
static
port
is
directly
connected
to
the
airspeed
indicator,
altimeter
and
rate
of
climb
indicator,
on
the
instrument
panel,
by
means
of
hose
and
tubing
routed
through
the
wing
along
with
the
pitot
line.
An
alternate
static
air
source
is
located
below
the
instrument
panel
in
front
of
the
pilot.
The
alternate
static
source
is
part
of
the
standard
system
and
has
a
shutoff
valve
which
closes
the
port
when
it is
not
needed.
A
placard
giving
instructions
for
use
is
located
on
the
instrument
panel.
9-18.
DIRECTIONAL
GYRO.
9-19.
GENERAL.
The
directional
gyro
is
a
flight
instrument
incorporating
an
air
driven
gyro
stabilized
in
the
vertical
plane.
The
gyro
is
rotated
at
high
speed
by
lowering
the
pressure
in
the
air
tight
case
and
simultaneously
allowing
atmospheric
air
pressure
to
enter
the
instrument
against
the
gyro
buckets.
Due
to
gyroscopic
inertia,
the
spin
axis
continues
to
point
in
the
same
direction
even
though
the
aircraft
yaws
to
the
right
or
left.
This
relative
motion
between
the
gyro
and
the
instrument
case
is
shown
on
the
instrument
dial
which
is
simular
to
a
compass
card.
The
dial,
when
set
to
agree
with
the
airplane
magnetic
compass
provides
a
positive
indication
free
from
swing
and
turning
error.
However,
the
directional
gyro
has
no
sense
of
direction
and
must
be
set
to
the
magnetic
compass,
since
the
magnetic
compass
is
subject
to
errors
due
to
magnetic
fields,
electric
instruments
etc.,
the
directional
gyro
is
only
accurate
for
the
heading
it
has
been
set
for.
If
the
gyro
is
set
on
270°,
for
instance,
and
the
aircraft
is
turned
to
some
other
heading,
there
can
be
a large
error
between
the
gyro
and
the
magnetic
compass
due
to
the
error
in
compass
compensation,
this
will
appear
as
gyro
precession.
The
gyro
should
only
be
checked
on
the
heading
on
which
it
was
first
set,
also
due
to
internal
friction,
spin
axis
error,
air
turbulence
and
airflow,
the
gyro
should
be
set
at
least
every
15
minutes
for
accurate
operation,
whether
it
has
drifted
or
not.
INSTRUMENTS
Revised:
12/4/79
2K13