Instruction Manual

G1000 / GFC 700 System Maintenance Manual - 200/B200 Series King Air Page 2-7
190-00915-01 Revision 9
2.1.9 Digital Air Data Computer (2)
The Garmin GDC 74B or 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
77/7800 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 2-22 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
2.1.10 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