190-02081-03
GFC 600H HFCS Part 27 STC Maintenance Manual
Rev. 3
Page 5-4
5.2 GMC 605H Mode Controller
5.2.1 LED Indicator Diagnosis Information
Table 5-2 summarizes the various states of the LED Indicators on the GMC 605H. Refer to Figure 2-2 for
LED position on the bezel.
NOTE
The FD or CPL LEDs will not illuminate in Normal mode unless a pitot-static test set is
connected to the rotorcraft for post installation testing and calibrations.
Table 5-2 GMC 605H LED Indicators
5.2.2 Crew Alerting System (CAS) Message Troubleshoot
The system messages in Table 5-3 will alert the crew in Normal mode to indicate an issue that needs to be
addressed prior to continued operation.
Table 5-3 GMC 605H CAS Troubleshooting
LED
(Button)
Indicator State
Status
FCS
Green
FCS engaged (normal operation)
Amber
Manual Disconnect (normal operation)
Red
The FCS has automatically disengaged from the
Flight Director commands. This may be due to an
internal failure, loss of AHRS data inputs, or the
servos are exceeding their engagement limits. Refer
to Table 5-3 for troubleshoot procedures.
Annunciated
Fault
Possible Cause
Corrective Action
PFT FAIL
(FCS LED –
Red)
• FCS DISC and/or FTR switch
to the GMC 605H and GFS
83 FCS DISC pins are not
powered.
• Servos are not
communicating or are wired
incorrectly for the configured
control axis position.
• Invalid configuration or
software loaded.
• Configured gains in the
GMC 605H don’t match the
gains in the GFS 83 servos.
• Internal unit failure.
• Invalid attitude data (includes
AHRS monitor and attitudes
outside the engage limits).
• Power cycle the GFC 600H FCS by cycling
the FCS circuit breaker.
• Ensure the GMC 605H, GFS 83, GSU 75H
and GMU 44( ) connectors are securely
mated to the units.
• Ensure wiring is correct.
• Ensure the FCS DISC and
• FTR switches on cyclic are not stuck or
shorted.
• Verify wiring of FCS DISC and
• FTR from circuit breaker to switch to the
GMC 605H and GFS 83.
• Troubleshoot the GSU 75H and GMU 44( ) in
accordance with Section 5.3.
• Reload software in accordance with
• Contact Garmin.