Piper Cherokee Six - Page 307

PIPER
CHEROKEE SIX
SERVICE MANUAL
SECTION VIA
LANDING GEAR
AND BRAKE SYSTEM
PA-32R-300
6A-1. INTRODUCTION.
In
this section are instructions
for the
overhaul, inspection
and
adjustment
of the various
components
of the PA-32R-300
landing
gear and
brake system.
Also are adjustments
for the electrical
limit, safety
and warning switches.
This section
though does
not cover the
hydraulic
function of
the landing
gear, except
brakes, and
this
information
may
be found in the
hydraulic section
listed as Section
VA.
6A-2.
DESCRIPTION.
The PA-32R-300
airplane is
equipped with
a retractable
tricycle
air-oil strut
type landing
gear
which
is hydraulically
operated
by
an electrically
powered
reversible
pump. A
selector handle on
the instrument panel
to the left of
the control
quadrant
is used
to select
gear UP or
DOWN positions.
Gear positions
are
indicated
by three
green
lights located
above
the selector
lever
for
gear down
and locked,
and
a red light
located
at the top
of the
instrument
panel for
gear
unsafe
positions.
There
is no light
to indicate
the gear
has fully
retracted
other than
all lights
are out.
As the landing
gear swings
to the down
position and
each downlock
hook
moves
into its locked
position,
a switch at
each hook
actuates to
the switch normally
closed
(NC)
circuit to
indicate by
a green light
that the individual
gear
is safely down
and locked.
The
activation
of all
three downlock
switches
will
also shut
the hydraulic
pump off.
As the
instrument
lights
are turned
on,
the green
lights
will
dim. When
the
gear begins
to
retract
and the
downlock
hook disengages,
the down
limit switch
actuates
to the
NC circuit
and in
series with
the NC
circuit
of the up
limit switch
allows
the gear unsafe
light
to come
on. The
gear unsafe
light
will remain
on until
the gear
is up and
all up limit
switches
are actuated
to
their normally
open (NO)
circuit.
The
red gear
unsafe
light also
operates
simultaneously
with
the
warning horn,
and
in
conjunction
they have
a twofold
purpose.
Their primary
purpose
is to give
warning
when
power
is reduced
below approximately
14 inches
of manifold
pressure
and
the landing
gear
has not
reached
the down
and locked
position.
This
circuit
is controlled
by the
three
paralleling
down
limit switches
connected
in series with
a throttle
switch
(Switch
"A")
located
in the
control
quadrant.
The
secondary
function
of
the warning
light
and
horn is
to
give
warning
when
the
gear
selector
handle
is up
when
the
airplane
is on
the
ground
or
airspeed
is below
that
required
to close
the
hydraulic
valve
and the
pump
switch
of the
backup
gear
extender
unit. When
the airplane
is setting
on
the ground,
the warning
circuit
is
controlled
through
the
NO side
of the safety
switch
(squat
switch) located
on
the left gear
and
the up
position
of the
selector
lever.
Should
the
airplane
be raised
from
the ground,
such as
in flight,
far enough
to move
the safety
switch
to its NC
position,
then current
is
directed
in
series
through
the hydraulic
pressure
switch,
the
pump
switch
(providing
airspeed
has actuated
the
switch
to its NO
position),
throttle
switch (Switch
"B")
and the
up
positioned
selector
lever. Throttle
switch
"B"
is located
forward
of the instrument
panel
directly
below the
arm of
the throttle
lever.
The up
limit, safety,
throttle,
pressure
and
LANDING
GEAR
AND BRAKE
SYSTEM
Revised:
1 1/4/83
2C7