Piper Cherokee Six - Page 308

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
selector
switch,
and pump
solenoids
are all
protected
by
the
landing
gear
control
and
warning
circuit
protector.
(Refer
to Section
X for
electrical
schematic.)
Each
landing
gear
is retracted
and
extended
by
a
single
hydraulic
cylinder
attached
to
the
drag
link
assembly
of the
nose
gear
and
the
side
brace
link
assembly
of the
main
gears.
As
the
gears
retract,
doors
partially
enclose
each
gear
through
mechanical
linkage.
The
gears
are
held
in
their
up
position
by
hydraulic
pressure
alone
on
the
cylinder.
There
are
no
uplocks
and
loss
of hydraulic
pressure
will
allow
the
gears
to
drop.
It
is preferred
that
the
gears
be
extended
and
retracted
with
the
use
of
the
gear
selector
handle;
however
in
the
event
of
hydraulic
loss
or
electrical
failure,
they
can
be
lowered
by
pushing
down
on
the
emergency
extension
lever
between
the
pilot
seats
or
they
will
drop
themselves
should
airspeed
drop
below
approximately
118
MPH,
engine
power
off.
In either
instant
the
hydraulic
valve
of
the
back-up
extender
unit
opens
to allow
hydraulic
pressure
to
neutralize
between
each
side
of the
cylinder
pistons.
The
emergency
extension
lever
can
also
be
used
to
manually
overcome
system
malfunctions
or.
to
meet
special
pilot
needs
such
as,
a
deliberate
wheels
up
landing
-
needed
for
emergency
landings
on
water,
or during
various
flight
maneuvers
where
airspeed
and
power
settings
would
normally
allow
the
gear
to
extend.
It
also
permits
gear
retraction
after
take-off
at
speeds
lower
than
those
normally
permitted
by
the
automatic
system.
When
using
the
manual
extension
lever,
the
gear
position
is
controlled
by
the
selector
switch,
regardless
of
airspeed/power
combinations.
An
override
latch
mechanism
is installed
which
allows
the
pilot
to
latch
the
extension
lever
in
the
up
override
position,
thus
bypassing
the
automatic
portion
of
the
system.
A
flashing
warning
light
is
mounted
below
the
gear
selector
lever
to
indicate
whenever
the
latch
is
in
use.
The
latch
is
disengaged
by pulling
up
on
the
extension
lever.
To assist
the
nose
gear
to
extend
under
these
conditions
are
two springs,
one
inside
the other,
mounted
on
arms above
the
gear links.
The
main
gears
require
no
assist
springs.
Once
the gears
are
down
and
the
downlock
hooks
engage,
a
spring
maintains
each
hook
in the
locked
position
until
hydraulic
pressure
again
releases
it.
A
further
description
of the
hydraulic
system
and
the
gear
back-up
extender
unit
may
be
found
in
Section
VA,
Hydraulic
System.
The
nose
gear
is steerable
through
a
45
degree
arc
by
the
use
of
the
rudder
pedals.
As
the
gear
retracts,
however,
the
steering
linkage
becomes
separated
from
the
gear
so
that
rudder
pedal
action
with
the gear
retracted
is not
impeded
by
the nose
gear
operation.
A
shimmy
dampener
is also
incorporated
in the
nose
wheel
steering
mechanism.
The
two
main
wheels
are
equipped
with
self-adjusting
single-disc
hydraulic
brake
as-
semblies
(Cleveland
30-65).
Optional
heavy
duty
(Cleveland
30-83)
dual-piston,
single
disc
brakes
may
also
be
installed
on
the
aircraft.
Toe
brakes
are
standard
on
both
the
pilot's
and
copilot's
rudder
pedals.
A
parking
brake
is
incorporated
with
the
handle,
and
may
be
used
by
pulling
back
on
the
handle
and
pushing
forward
on
the
button
to the
left
of
the
handle.
To
release
the
hand
brake,
pull
aft
on the
handle
and
allow
it
to swing
forward.
Hydraulic
fluid
for
the
cylinders
is supplied
by
a
reservoir
installed
on
the
left
forward
side
of
the
firewall.
LANDING
GEAR
AND
BRAKE
SYSTEM
Revised:
12/15/80
2C8