Survey of arc tracking on aerospace cables and wires

The paper gives a survey of the phenomenon `Arc Tracking of Wires´ which has been observed for the first time in wiring systems of aircraft and which recently has occurred also in spacecraft. Aircraft organizations are aware of this phenomenon and have tried to provide solutions to cope with this new wire failure, i.e. modification of cable design and manufacture, avoiding pure polyimide insulation, and development of test methods. As regards space systems, the recognition of this phenomenon with its possible consequences has led to the development of test methods and to the introduction of new wire requirements within the framework of the Columbus Program. The available data do not establish with certainty a correlation between test results obtained for aircraft systems and the behavior expected on spacecraft. The untidy nature of arc tracking has been shown with the different kinds of events reported. In test laboratories, significant variations of results make this failure phenomenon even more difficult to define. From the data summarized in the survey it is apparent that the failure conditions vary with numerous conditions of electrical network, environment, cable design and aging parameters. Whereas the arcing phenomenon is essentially influenced by the environment and network conditions, the susceptibility to tracking is more dependent on the chemical nature of the insulation. Definitions are also presented in the survey to complete the understanding of the phenomenon