Engine Vibration Test - Garmin GI 275 Installation Manual

6.4.2.1 Heading Offset Compensation
The Heading Offset Compensation Procedure is not required if it was determined in Section 6.4.2 that all
calculated heading errors are between -3° and +3° inclusive. If at least one heading error was greater than
3° or less than -3°, but all heading errors were between - 5° and +5° inclusive, use the Heading Offset
Compensation Procedure to correct the errors. Otherwise, physically correct the appropriate GMU 11/44B
installation before performing the Heading Offset Compensation Procedure.
NOTE
If the Heading Offset Compensation Procedure must be performed on both AHRS #1 and
AHRS #2, it is permitted to run the procedure below simultaneously on two displays.
The Magnetometer Calibration Procedure must be performed before the Heading Offset Compensation
Procedure. Performing the magnetometer calibration removes any stored heading offset values.
1. Start the aircraft engine in accordance with the aircraft AFM/POH.
2. Power the displays on in Configuration mode.
3. Touch Heading Offset from the Procedure menu (Calibration/Test→ Attitude/Heading).
4. Select the desired AHRS unit to calibrate from the AHRS Unit selection.
5. Complete the Before Calibration steps listed on the display; touch each step when complete so that
a green check mark appears next to the selection.
6. Touch the Calibrate button when it becomes active to start the calibration procedure.
7. Follow the on-screen commands to complete the calibration.
6.4.3

Engine Vibration Test

The calibration procedures in Section 5.7.1.1 through Section 6.4.2.1 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 aircraft engine in accordance with the aircraft AFM/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.
6. Gradually increase the engine throttle in small increments from idle to full and back to 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.
190-02246-10
Rev. 11
GI 275 Part 23 AML STC Installation Manual
Page 6-25