190-02081-03
GFC 600H HFCS Part 27 STC Maintenance Manual
Rev. 3
Page 7-20
7.7.7 Run-Up Vibration Check (GSU 75H OR GRS 79H Only)
WARNING
Ensure the aircraft is outside in a location where the engine(s) can be run safely. Ensure
that all equipment and personnel are clear of the tail and main rotor before proceeding with
these procedures.
The following procedure must be performed for each AHRS. The run-up procedure can be done
simultaneously on each display. Follow the prompts on each display. Initiate the Engine Run-Up Check
procedure by performing the following steps:
1. On the GDU, select
Engine Run-Up Test
from the Procedure menu (
Home → Calibration/Test
→ Attitude/ Heading
).
2. Select the desired AHRS unit to calibrate via the AHRS Unit selection.
3. Follow the Before Test checklist items on the display and select each as they are completed. When
all checklist items have a green checkmark, the
Test
selection will become active.
4. Select
Test
to begin the procedure.
5. Follow the on-screen commands except rotorcraft execute the Run-up Check at ground idle.
If failures are indicated on the GDU, the engine run-up check may be repeated up to two more times. If the
check does not pass after three attempts, the installation cannot be considered reliable until the source of
the vibration problem is identified and fixed. In the event of repeated failures during the engine run-up
check, record the values that are reported to be out of range for future reference.
The following are potential causes for a failure of the engine run-up check:
• Vibration motion of AHRS and/or GMU 44( ) caused by neighboring equipment and/or supports
• Mounting screws and other hardware for AHRS and/or GMU 44( ) are not firmly attached
• AHRS connector is not firmly attached to unit
• Wiring connected to the remotely mounted AHRS or GMU 44( ) is not firmly secured to
supporting structure
• A dynamic component is significantly out of balance
After the AHRS calibration is complete, the AHRS attitude and heading information displayed will
become valid within 1 minute of power-up in Normal mode.