Regardless of the particular application on an aircraft, at some point in a wire/cable’s service life, it will become exposed to fluids. These may be fuel, hydraulic fluid, cleaners, deicers, and/or a variety of other fluids. It is critical that the wire/cable insulation is not adversely affected with exposure to these fluids. In particular, the insulation should not swell, crack, shrink, or show any signs of deterioration after fluid exposure. Typical forms of degradation from this test include swelling or softening of insulation materials, delamination of tape wrapped insulation, and reduction in the electrical properties of the insulation.
At the end of the fluid immersion test, the report shall include the percentage diameter change of the specimen and the results of the bend and wet dielectric tests, if applicable to the particular specification.
In this test, a sample is exposed to a variety of fluids. The duration and temperature of the exposure varies and is defined by the test standard.