NorthStar 1200-02-01, Installation Manual

Page: 24 / 56

Section Two—Installation Instructions
PAGE 20 M3 GPS INSTALLATION MANUAL Revision D
MESSAGE
button will show, and is not required, even for IFR installations.
The
APPROACH
annunciator signal is available on both pins 11 and 30 of
P16, although these pins are electrically independent. The earliest
en route-approved M3s required a
VFR
annunciator (connected to pin 11),
and described pin 30 as a “future
APPROACH
annunciator.” Later approv-
als removed this requirement for a
VFR
annunciator.
For new M3 installations, the
APPROACH
annunciator may be connected
to either pin 11 or pin 30.
For en route-approved installations that are being upgraded to non-preci-
sion approach status, determine which configuration of annunciators had
been previously installed from the following list:
•
If neither
VFR
nor
APCH
is present, install a new blue or green annun-
ciator labelled
APCH
and connect it to either pin 11 or pin 30 of P16.
•
If
VFR
is not present, but
APCH
is present, no color change is required.
•
If
VFR
is present, but
APCH
is not present, change the legend from
VFR
to
APCH
, and ensure that the color is either blue or green.
•
If both
VFR
and
APCH
annunciators are present, the
VFR
annunciator
must be disabled. Otherwise, both
VFR
and
APCH
would be illumi-
nated when the M3 enters final approach mode.
The
APPROACH
annunciator is either blue or green.
CDI/HSI and
autopilot wiring
For an IFR installation, an indicator showing cross-track deviation must be
located in front of the pilot.
•
CDI/HSI — Wire as shown in Figure 9, using an appropriate switch-
ing device between the M3 and the instrument to enable selective
control by the pilot.
•
Nav Flag — Wire as shown in Figure 9. The M3 is designed to
directly drive a flag with a 1,000-Ohm input impedance. It should be
wired through the switching mechanism. A Nav Flag with a
300-Ohm movement may require a 2.7 K resistor installed in series
NOTE:
The M3 will not drive a CDI with a built-in converter, such as
the KI-208. Most others, however, having a 1,000-Ohm move-
ment and requiring about 150
µ
A or 150 mV full scale, will
work.