Piper SENECA III - Page 274

SECTION 9
PIPER
AIRCRAFT
CORPORATION
SUPPLEMENT 4
PA-34-220T,
SENECA III
(5)
Heading Mode (HDG):
Set
the
heading
bug
to
the
desired
heading
on
the PNI, depress
the
HDG
switch
on
the
Mode Controller
and
HDG
will
be
displayed
on
the annunciator panel The FDI and/or AP
will
command.
a
turn
to
the
heading
selected.
The pilot
may
then
choose
any
new
heading
by
merely
setting the bug
on a new
heading. The
FDI
and/or
AP
will automatically
command
a
turn
in
the
direction of
the
new
setting.
To
disengage
the
HDG
mode, depress
the HDG
switch
on
the Mode
Controller
and
observe
the HDG
light
go
out
on
the
annunciator.
The
HDG
mode
will
automatically
-
disengage
when
APPR
or
NAV
CPLD
is achieved.
(6)
Navigation
Mode (NAV):
The
Navigation
mode
may
be
selected
by tuning
the NAV
receiver
to
the
desired frequency,
setting
the
CDl
tothedesired
radial and
depressing the NAV
switch
on
the
Mode Controller.
The
annunciator
will
indicate
NAV
ARM
until
capture
of
the
selected
course,
unless
the NAV
switch
is
engaged
with
wings
level
and
a
centered
needle
on
the
CDI.
Then the mode
will
go
directly
to
NAV CPLD
as
displayed
on
the
annunciator
panel.
The
system
can
intercept
at
any
angle
up
to
90°
and
will always
turn
toward
the
course
pointer.
If
a
condition
requiring
a
capture
exists
at
mode
engagement,
the
pilot
is
required
to
set
up
an
intercept
angle
using
either
HDG
or
FD
mode. NAV
may
be
disengaged by
depressing
the
NAV
switch
or
by
engaging
HDG
when
in
NAV
CPLD
or
engaging APPR
when
in NAV
CPLD
or
NAV
ARM.
CAUTION
The
"NAV"mode
of
operation will
continueto
provide
airplane
commands
and/or
control
without
a
valid VOR/
LOC signal
(NAV
flagin
view).
Also
erroneous
navigation
information
may
result
from
COMM
radio
interference
with
the
NAV
radio.
This
erroneous
infor-
mation
may
cause
premature
NAV
captures
as
well
as
erroneous
steering
information.
Should
this
occur
reselect
HDG
mode
and then
reselect
NAV
mode.
REPORT:.VB-1110
ISSUED:
APRIL
21,
1981
9-30,
12 of
16