Delamination and Blocking

While on an aircraft, wire/cable may be exposed to high temperatures while in operation. Wire/cable that softens or deforms when exposed to high temperature is a problem for the health of the aircraft and to those that maintain the fleet. Testing for delamination (the separation of layers of insulation) and blocking (adhesion either to a […] Read more

Insulation Wrap Back Test

During normal operation and maintenance cycles wire/cable are subjected to stresses, both mechanical and environmental, that challenge the integrity of wire/cable insulation. The wrap back test subjects wire/cable specimens to a very tight bend diameter in addition to conditioning at elevated temperatures to determine if a specific insulation is prone to cracking. A specimen is […] Read more

Contact Resistance

A potential lossy area in electrical circuits (both for power and signal) is at the contact points. Poor mating, contaminated surfaces, poor crimping, and/or damaged plating can all add resistance to the circuit. A means of assessing this impact is by measuring the contact resistance. Contact resistance refers to the electrical resistance that can be […] Read more

Delamination/ Lamination Sealing

The uniformity and cohesion of layered tape wrapped insulation is a critical measurement of wire/cable quality. When exposed to elevated temperatures near insulation’s maximum temperature rating, the insulation will often soften, deform, and may cause insulation layers to lose adhesion and separate. This delamination of the insulation layers can lead to fluid ingress and impact […] Read more

DC Leakage

In practice, the energy stored in capacitors will dissipate and discharge through the dielectric. The leakage rate is based on a combination of factors that include: the dielectric material, component age, use, temperature, and applied voltage. The DC leakage test is a test that helps to identify the long-term power storage capacity of capacitors and […] Read more

Attenuation (Insertion loss)

A voltage pulse (or signal) placed on a wire/cable will progressively degrade along a wire/cable length due conductor resistance, dielectric material, temperature, signal frequency, and other factors. In short, attenuation is the loss of signal strength. Those wires/cables with lower attenuation are often preferred as less energy is needed for signal transmission. The purpose of […] Read more

Fungus Resistance

Wire/cable insulations that are prone to surface fungus growth can impair maintenance activities by obscuring wire identifications, concealing wire/cable damage, and potentially creating a health hazard for the maintainers. Although fungus resistance is a common trait with modern aerospace wire/cable constructions, the need to verify the fungus resistance exists to ensure no in-service surprises. The […] Read more

Humidity Resistance

The humidity resistance test seeks to evaluate the impact of prolonged heat and humidity exposure to wire/cable insulation. This accelerated environmental test is meant to simulate the environmental conditions in Severe Wind and Moisture Prone (SWAMP) areas on aircraft to analyze the possible detrimental effects. A sample is considered to have failed if there has […] Read more

Wrap Back Test

The wrap back examines a wire/cable’s insulation susceptibility to breach when tightly wrapped around itself and exposed to elevated temperatures. This test is usually required in the individual wire specifications as part of the insulation integrity assessment. After the elevated temperature exposure, the specimen is visually examined for any insulation cracks (or delamination in the […] Read more

Velocity of Propagation

The velocity of propagation (also known as the Phase Velocity) test measures the speed of electrical signal transmission down a wire/cable. The velocity of signal propagation is typically represented as a fraction of the speed of light in a vacuum and is primarily impacted by the wire/cable dielectric. This test may also be used as […] Read more

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