Instruction Manual
Instructions for Continued Airworthiness 190-01190-11 Rev. 1
for G500H in Robinson R44 Series Rotorcraft Page 14 of 20
Alert Text Cause Solution
SW MISMATCH
GDU software version strings do not
match.
Verify the correct SW is loaded
TERRAIN DSP Terrain, Airport Terrain, or Obstacle
database error.
Update/Reload database
TRAFFIC FAIL The traffic information system has
failed.
The GDU 620 is not receiving traffic
information from the traffic sensor. Verify
wiring between GDU 620 and traffic
sensor.
The GDU 620 is receiving information
from the traffic sensor, but the information
is indicating that the traffic sensor has
failed. Troubleshoot traffic system.
TRAFFIC STDBY The traffic information system is in
Standby mode while the aircraft is
In-Air.
TRK LOST GPS1 TRK lost. HSI defaulted to
GPS2 TRK.
2.7 Removal and Installation Information
If any G500H LRUs are removed and reinstalled or a new unit is installed, verify that the LRU unit power-
up self-test sequence is successfully completed and no failure messages are annunciated on the GDU
620 display.
If any work has been done on the rotorcraft that could affect the system wiring or any interconnected
equipment, verify the G500H system unit power-up self-test sequence is successfully completed and no
failure messages are annunciated on the GDU 620 display.
Whenever removing or installing units, remove power from the LRU by removing aircraft power or
opening the LRU circuit breaker.
2.7.1 GDU™ 620 Unit
2.7.1.1 Removal
1. Remove the six mounting screws from the bezel of the GDU 620.
2. Pull the GDU 620 far enough out from the instrument panel to access the three rear connectors.
3. Disconnect the rear connectors.
4. Remove the GDU 620.
2.7.1.2 Installation
1. Visually inspect the connectors to ensure that there are no bent or damaged pins. Repair any
damage.
2. Connect the rear connectors, ensuring that each slidelock is secured on both sides.
3. Set the GDU 620 into place.
4. Install the six mounting screws into the bezel of the GDU 620.










