Technical data

13773-001
34-40
Page 1
INDEPENDENT POSITION DETERMINING
1. DESCRIPTION
This section covers that portion of the system which provides information to determine position from
sources which are mainly independent of ground installations. This includes the GPS, multifunction display
(MFD), and Stormscope systems.
Two VHF communications (COM) transceivers are installed to provide VHF communication. The transceiv-
ers and integrated controls are mounted in the Garmin GNS 430 units. The transceivers receive all narrow-
and wide-band VHF communication transmissions transmitted within range of the selected frequency. The
antennas pick up the signals and route the communication signals to the transceivers, which digitize the
audible communication signal. The digitized audio is then routed to the audio control unit for distribution to
the speakers or headphones.
COM 1 - The upper Garmin GNS 430 is designated COM 1. The Garmin GNS 430 control panel provides
COM 1 transceiver active and standby frequency indication, frequency memory storage, and knob-oper-
ated frequency selection. The COM 1 antenna is located above the cabin on the airplane centerline. 28
vdc for COM 1 transceiver operation is controlled through the Avionics Master Switch on the bolster switch
panel and supplied through the 7.5-amp COM 1 circuit breaker on the Essential Avionics Bus.
COM 2 - The lower Garmin GNS 430 is designated COM 2. The Garmin GNS 430 control panel provides
COM 2 transceiver active and standby frequency indication, frequency memory storage, and knob-oper-
ated frequency selection. The COM 2 antenna is located on the underside of the cabin on the airplane cen-
terline. 28 vdc for COM 2 transceiver operation is controlled through the Avionics Master Switch on the
bolster switch panel and supplied through the 7.5-amp COM 2 circuit breaker on the Non-Essential Avion-
ics Bus.
GPS signals are received by an antenna mounted inside the fuselage under the forward headliner or by an
antenna mounted inside the fuselage under the instrument console. Refer to GNS 430 Installation Manual
indexed in the List of Publications in the front of this manual for additional maintenance information on the
GNS 430
The ARNAV ICDS-2000 multifunction display (MFD), located on the instrument panel, provides 10.4” diag-
onal, color depiction of navigational data from its own database and position and flight-plan data from the
GPS receiver. Refer to ARNAV System’s ICDS 2000 Operations Handbook indexed in the List of Publica-
tions in the front of this manual for additional maintenance information on the multifunction display.
The Stormscope processor and antenna detect electrical discharges associated with thunderstorms. This
information is then sent to the MFD that plots the locations of the associated thunderstorms.
2. MAINTENANCE PRACTICES
A. Garmin GNS 430 GPS/COM/NAV (See Figure 34-401)
(1) Removal - Garmin GNS 430 GPS/COM/NAV
(a) Ensure BAT 1, BAT 2, and AVIONICS master switches are in off position.
(b) Pull ESSENTIAL and NON-ESSENTIAL AVIONICS circuit breakers.
(c) Insert hex wrench into front panel bolt hole and engage hex bolt.
(d) Turn locking screw counterclockwise to loosen locking cam. Cam will move the trans-
ceiver unit out 1/4” and disengage from the electrical connectors.
(e) Pull transceiver from mounting tray
30 Nov 2000