CarlisleIT tray assemblies are designed to conform to all ARINC criteria for cooling and filtration in a variety of extreme environments. Our custom Cooling and Air Filtration systems excel at reducing heat build-up and minimizing moisture and dirt ingression, significantly increasing the Mean Time Between Failure (MTBF). When needed, CarlisleIT can design cooling solutions appropriate for both pressurized cabin and high altitude applications to be installed in every zone of modern aircraft.

Avionics Systems Equipment Cooling Guidelines

There are three different methods used to control air temperature for avionics systems equipment LRUs.

Method A - Convection Airflow Cooling: LRUs which do not require stand-alone air cooling systems use a special cutout in the equipment tray, allowing heat to dissipate away from the LRU.

Method B - Supplied Airflow Cooling: Trays integrated onto a shelf racking system will incorporate a metering plate with metering plugs to regulate the available aircraft supplied air flow.

Method C - Forced Airflow Cooling: LRUs with special cooling requirements use a stand-alone positive pressure cooling fan/plenum assembly to maintain proper temperatures on the ground or during in-flight operations. Cooling fans can be mounted on the rear, side, or bottom of the equipment tray. CarlisleIT specializes in custom design solutions for complex cooling problems in Avionics Systems, and has many "off-the-shelf" commercial designs of tray and fan combinations available that meet ARINC 600 Level 1 maximum values.

Cooling requirements vary considerably with different aircraft and avionics systems. To determine the optimal cooling requirements for your specific application it is important to compile the following information.

1a. Avionics system type (SATCOM, TCAS, IFE, etc.), original equipment manufacturer (OEM), and equipment model number...or

1b. Maximum heat dissipation of the LRU: How much cooling air is required? Pressure drop across the LRU: Is an LRU Air Flow Impedance Curve or an LRU Impedance Equation available? Or, does the LRU conform to ARINC 600 Level 1 or Level 2 cooling?

2. LRU environment: Is the environment pressurized or non-pressurized?

3. Available power for the fan: 115 VAC, 400 Hz Single Phase or 28 VDC?

4. Is air filtration required?