Piper SENECA III - Page 369

PIPER
AIRCRAFT
CORPORATION
SECTION 9
PA-34-220T,
SENECA
III
SUPPLEMENT 18
(c)
TRIM
SYSTEM
The
autopilot
is provided
with
an
electric
elevator trim
system
having
two
modes
of
operation.
When
the
autopilot
is
engaged
and
the
trim
master
switch
is ON,
automatic
electric
trim
(autotrim)
is
provided. When
the autopilot
is disengaged.
command electric
elevator
trim
is
available by
use
of the
control
wheel switch
provided
or
by
use
of the
primary trim
control
wheel.
The electric
elevator
trim
system
has been
designed
to
withstand
any
type
of
single
failure,
either
mechanical
or
electricaL
without
uncontrolled
operation
resulting.
The
automated
system
self
test
circuit
provided,
in
conjunction
with
a
functional
check,
described below,
will
uncover
internal
failures
that
otherwise
could remain
undetected
and
thus
compromise
the
fail-safe
properties
of
the
system.
Proper
operation
of
the-system is,
therefore,
predicated
on
conducting
the
following preflight
check first
flight
of
each
day.
If the
trim
system
fails
any
portion of
this
test, turn
the trim
switch OFF
and
pull the
trim
circuit
breaker,
until
the
system
is
corrected.
The
command
electric trim switch
on
the left
portion of
the
pilot's
control
wheel
has
two
functions:
(1)
When the
top
bar
(AP
OFF) is
pressed, it
disconnects
the
autopilot.
(2)
When the
top
bar
is
pressed
and
the
rocker
is
moved
forward,
nose
down
trim
will
occur;
when
moved
aft,
nose
up
trim will
occur.
Command
Trim
-
Before
the
First Flight
of
Each
Day
(1)
Trim
master
switch
-
ON.
(2)
Verify
normal
trim UP
and DOWN
operation with
control
wheel
switch.
(3) Press
-
center
bar
only
-
then
release
center
bar.
(4)
Push
rocker
fore and aft
-
only.
Trim should
not
operate
with
either
separate
action.
Any
failure of the
preceding
operations
indicates
that afailure
exists
in the
system
and
the Command
Trim
shall
not
be
operated until
the
failure
has been
identified and corrected.
ISSUED:
APRIL 21,
1981
REPORT:
VB-1110
7
of 12,
9-119