The GCU 477 Line Replaceable Unit (LRU) provides alphanumeric, softkey and flight planning functions keys used to interface with the Garmin G1000 Integrated Flight Deck. In addition, the GCU 477 provides COM/NAV tuning capabilities.
GCU 477 FMS Keyboard
The system is electrically connected to the LH BUS and it is protected from over current by means of a breaker (5A) located in the breaker panel.
There are 4 input modes that perform different functions depending on which mode is activated.
FMS - MFD/PFD general input
Typing on keypad will input the key to active input box on MFD/PFD.
COM -COM standby frequency input
Typing on num keypad will activate standby frequency edit mode and input the key.
Pressing COM key will toggle tuning box to COM 1/2.
Pressing swap key will swap COM active and standby frequency.
NAV - NAV standby frequency input
Typing on num keypad in will activate standby frequency edit mode and input the key.
Pressing NAV key will toggle tuning box to NAV 1/2.
Pressing swap key will swap NAV active and standby frequency.
XPDR - Transponder code input on PFD
Typing on num keypad will input the key to Transponder code edit box.