Instruction Manual

Page 2-6 G1000 / GFC 700 System Maintenance Manual - 200/B200 Series King Air
Revision 8 190-00915-01
2.1.8 Digital Air Data Computer (2)
The Garmin GDC 74B or optional GDC 7400 air data computers compile information from the pitot/static
system and various outside air temperature (OAT) and awareness sensors and provide digital air data
computations to the G1000 system. The GDC communicates with the GIA 63W, GDU 1040A, and GRS 77
using ARINC 429 digital interface. The unit is mounted behind the instrument panel. GDC 1 receives
primary electrical power from the Essential Bus and a secondary power supply from Dual Fed Bus No. 1.
GDC 2 receives power from Dual Fed Bus No. 2. GDC 1 and GDC 2 connect to existing pitot/static ports.
Refer to Figure 2-20 for a schematic of the aircraft’s pitot/static system and its connections to the G1000
STC installed equipment.
IMPORTANT!
Aircraft modified by this STC are eligible to be approved for RVSM operation. RVSM
critical maintenance instructions contained in this document must be followed in order
to guarantee performance within RVSM specifications.
GDC 74B GDC 7400 (optional)
Figure 2-8, Air Data Computer
2.1.9 OAT Probe (2)
The Garmin GTP 59 OAT Probes provide the GDC 74B or optional GDC7400 with air temperature data.
The OAT probes are mounted to the bottom of the fuselage at F.S. 113.5.
Figure 2-9, OAT probe