Garmin GI 275 Maintenance Manual page 78

5.7.1.3 Calibrate Pitch/Roll Offset
This procedure must be completed on each GI 275 with an integrated ADAHRS. This procedure can be
conducted for each AHRS simultaneously on each display. The rotorcraft must be leveled to within 0.25°
of zero pitch and zero roll using the procedures in the rotorcraft maintenance manual or RFM/POH. The
following procedures must be completed with the engine off:
1. Navigate to the Calibrate Pitch/Roll page (Calibration/Test → Attitude/Heading → Calibrate
Pitch/Roll).
2. Complete the steps listed on the display. Touch the Start button to begin the calibration procedure.
3. Follow the on-screen command prompts.
The Magnetometer Calibration (Section 5.7.1.7) and Compass Swing (Section 5.7.1.8) are completed after
the initial Engine Run-up Test has been completed.
5.7.1.4 Manual Pitch/Roll
Allows the pitch and roll values to be set manually.
5.7.1.5 Engine Vibration Test
The calibration procedures in Section 5.7.1.2 through Section 5.7.1.4 do not have to be completed prior to
performing this procedure.
For dual AHRS installations, the following procedure must be performed for each AHRS on the display it
is wired to. The procedure can be done simultaneously on each display. Follow the prompts on each
display. Initiate the Engine Vibration Test by performing the following steps:
1. Start the rotorcraft engine in accordance with the RFM/POH.
2. Power on the display(s) in Configuration mode.
3. Navigate to the test page (Calibration/Test → Attitude/Heading → Engine Vibration Test).
4. Complete the Before Calibration steps listed on the display; touch Next after completing each step
to move to the next step.
5. Touch Start to begin the procedure.
CAUTION
Follow all the on-screen prompts EXCEPT execute the run-up check between GROUND
IDLE and FULL ROTOR RPM.
6. Smoothly increase the throttle from ground idle to full rotor RPM for flight and then back to
ground idle over a period of approximately 1 minute.
7. Observe the readout on the display while performing the engine run-up. The values shown during
the test must not exceed 100 in order for the test to be considered a pass. Values in excess of 100
will cause the display to indicate a failure.
8. Select DONE when finished.
If failures are indicated, 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.
190-02246-C2
Rev. 3
GI 275 Part 27 AML STC Maintenance Manual
Page 5-18