Cirrus SR22 Pilot Operating Handbook page 487

Cirrus Design Section 9
SR22 Supplements
GNS 430W
The GNS 430W, designated as the primary navigator (GPS 1),
includes all of the features of the GNC 420W with the addition of IFR
certified VOR/Localizer and Glideslope receivers. In the event a
second GNS 430W is installed, the second unit will function as
described below except that the GPS Navigator is designated GPS 2,
the NAV receiver is designated NAV 2, and the VHF communications
receiver is designated COM 2.
GPS 2 Navigator and VHF NAV is powered by 28 VDC through the
Avionics Master Switch and the 5-amp GPS 2 circuit breaker on the
Avionics Non-essential Bus. 28 VDC for transceiver operation is
supplied through the Avionics master Switch and the 7.5-amp COM 2
circuit breaker on the Avionics Non-Essential Bus.
The following describes a single GNS 430W unit and its functions.
GPS Navigator
The GNS 430W Navigator is coupled to the airplanes HSI and MFD.
Typically, the second GPS Navigator provides backup and is approved
for VFR use only. If the second GPS is also a GNS 430W, it will be
coupled to the CDI and is also approved for IFR use.
The GPS 1 antenna is located on top of the fuselage slightly aft of the
rear window along the airplane centerline and the GPS 2 antenna is
located on top of the fuselage slightly forward of the rear window along
the airplane centerline. The GNS 430W Navigator is powered by 28
VDC through the 5-amp GPS 1 circuit breaker on the Avionics
Essential Bus.
Navigation (NAV) Receiver
The GNS 430W provides an integrated Navigation (NAV) receiver with
VHF Omnirange/Localizer (VOR/LOC) and Glideslope (G/S) capability.
The NAV antenna is mounted on top of the vertical tail.
28 VDC for navigation receiver operation is controlled through the
Avionics Master Switch on the bolster switch panel and supplied
through the 5-amp GPS 1 circuit breaker on the Avionics Essential
Bus.
P/N 13772-132 7 of 10
Revision 01: 11-11-07