Rev A, August 31, 2016 6 Manual Number 9018670
Table 1.3
SECTION 2 PRE-INSTALLATION CONSIDERATIONS
2.1 COOLING
The TC234 product does not require external cooling or contain internal active cooling. Cooling of the unit
occurs exclusively through passive conduction through the base or radiated cooling across the metal
case. Additional cooling can be realized through convection (exposure to free moving air) or conduction
(mounting to a thermally conductive metal surface). These methods are not required to achieve rated
performance but can help prevent potential overheating and extend life when the unit is operated at full
power or during overload conditions. Specifically, mounting the unit to a metal surface is preferred, but
not required.
2.2 EQUIPMENT LOCATION
The TC234 is designed for mounting flexibility, allowing for installation inside or outside the pressure
vessel with no requirement for temperature control. In addition to altitude and temperature resistance, the
unit is also designed to withstand high levels of condensing humidity. However, installation locations
where the unit could be subject to standing or direct water exposure should be avoided. The unit can be
mounted in any orientation. Clearance should be provided for the mating connector and may require as
much as five inches past the unit connector to allow for back shell access to the connector.
2.3 ROUTING OF CABLES
The wires and cable bundle associated with the unit are heavy gauge wire and carry significant power. Be
aware of routing cables near other electronics or with other wire bundles that may be susceptible to high
energy flow.
Avoid sharp bends in cabling and routing near aircraft control cables. Also avoid proximity and contact
with aircraft structures, avionics equipment, or other obstructions that could chafe wires during flight and
cause undesirable effects.
2.4 LIMITATIONS
The TC234 contains an internal DC-to-DC conversion function to produce the rated output as
specified. This function meets the requirements of FAA TSO-C71. The TC234 also creates an
initial translation of a direct current (DC) input to the intermediate DC voltage, which then gets
converted to the rated output. This initial translation of DC-to-DC power is considered a non-TSO
function. This is due to the lack of an available DC-to-DC Technical Standard Order. However,
the DC-to-DC function is fully tested and verified per the equipment requirements and design as
well as the stated environmental requirements. The data to support the non-TSO function have
been submitted to and reviewed by the FAA along with the TSO-C71 requirements and
functionality.
The conditions and tests for TSO approval of this article are minimum performance standards. Those
installing this article, on or in a specific type or class of aircraft, must determine that the aircraft installation
conditions are within the TSO standards. TSO articles must receive additional installation approval prior
to being operated on each aircraft. The article may be installed only according to 14 CFR Part 43 or the
applicable airworthiness requirements.
