Air Circulation And Cooling; Compass Safe Distance - Garmin GTR 225 Installation Manual

3.5 Air Circulation and Cooling

CAUTION
To avoid damage to the GTR/GNC, take precautions to prevent Electro-Static Discharge
(ESD) when handling the GTR/GNC, connectors, fan, and associated wiring. ESD
damage can be prevented by touching an object that is of the same electrical potential as
the GTR/GNC before handling the GTR/GNC itself.
The GTR/GNC unit meets all requirements without external cooling. However, as with all electronic
equipment, lower operating temperatures extend equipment life. Reducing the operating temperature by
15° to 20°C (27° to 36°F) reduces the mean time between failures (MTBF).
Units tightly packed in the avionics stack heat each other through radiation, convection, and sometimes by
direct conduction. Even a single unit operates at a much higher temperature in still air than in moving air.
Fans or some other means of moving the air around electronic equipment are usually a worthwhile
investment.
The GTR/GNC has a cooling fan integrated into the chassis to draw forced-air cooling through the unit.
There are inlets along the right side of the GTR/GNC chassis that allow air to flow through the unit. Ensure
that there are no obstructions to the air inlets or fan exhausts. Air should be able to freely flow from the
chassis inlets to the fan outlet on the rear of the unit.

3.6 Compass Safe Distance

After reconfiguring the avionics in the cockpit panel, if the GTR/GNC unit is mounted less than 12 inches
from the compass, recalibrate the compass and make the necessary changes for noting correction data.
GTR 225/GNC 255 TSO Installation Manual
Page 3-4
190-01182-02
Rev. B