Development of the Electric Wiring Interconnection System Risk Assessment Tool

摘要

The Federal Aviation Administration developed a Risk Assessment Tool (RAT) for the Electrical Wiring Interconnection System (EWIS). This report documents further developments of that RAT. The developments include the results of a paired comparison workshop in which expert judgment was elicited on the effects of wire environment on wire failure rate. This data was used to develop a multivariate function that when it is scaled using historical failure data from the emergency path lighting system, the function estimates the failure probabilities of wires for most of the environmental and physical conditions found on aircraft. A damage potential analysis was expanded to include a model of damage to structure that depends on the power, energy, and heat dissipation of an electrical arc. An agreement between the developed model and damage data was acceptable. However, potential improvements to the model have been identified. Methodologies and software tools have been developed to improve the accuracy and efficiency of importing the required aircraft EWIS data into the tools model database. Using these tools, 7783 wires, 1774 bundle sections, and 579 connectors were modeled and imported into the database. Finally, a prototype report was generated to improve consistency between the reports generated by the EWIS RAT and Aircraft Certification Office expectations. These improvements have been integrated into the EWIS RAT.