Garmin GI 275 Maintenance Manual page 113

5.14.2.3 Altimeter Check
The GI 275 standby altitude displays must be verified per Title 14 of the CFR 91.411 and Part 43
Appendix E, with the following exception to 14 CFR Part 43 Appendix E, paragraph (b)(1):
• The tests of sub-paragraphs (iv) (Friction) and (vi) (Barometric Scale Error) are not applicable to
the GI 275 due to the internal ADAHRS interface and instrument display being digital
5.14.2.4 Calibrate Static Pressure
This procedure is used to perform an altimeter calibration, if required.
The Static Pressure Calibration requires the use of a pressure control system (test set) with an altitude
accuracy of at least ±5 feet at sea level and ±20 feet at 30,000 feet. It is necessary to re-calibrate to sea level
(0 feet), 10,000 feet, 20,000 feet, and optionally to 30,000 feet. The calibration is allowed to be finished
after the 20,000 feet calibration if the aircraft operational ceiling is below 20,000 feet.
CAUTION
To avoid damaging the GI 275 pressure sensors, both the pitot and static ports must be
connected to the test set.
CAUTION
Prior to performing the Calibrate Static Pressure procedure, perform a Static System Leak
Test in accordance with 14 CFR Part 43 Appendix E.
1. Navigate to the Calibrate Static Pressure page (Calibration/Test → Attitude/Heading →
Calibrate Static Pressure).
2. Ensure the on-screen instructions have been followed. Touch the OK/Next/Start buttons to
continue to the next screen.
3. At each calibration point, the display will indicate the pressure altitude to set (e.g., "Set pressure to
sea level"). Once the altitude is set, touch Ready to calibrate.
a. During the calibration at each pressure, the pressure must be held constant for 30 seconds for
the calibration step to be successful. The calibration may be canceled at any point should the
test setup require adjustment before repeating.
4. Select Done when the calibration is successfully completed.
190-02246-11
Rev. 1
GI 275 Part 23 AML STC Maintenance Manual
Page 5-42