1 The build-up and subsequent discharge of static electricity has the potential to create hazardous conditions for both aeroplane systems and the aeroplane occupants. Static can cause physical injury, interfere with installed electrical/electronic equipment, and cause ignition of flammable vapours. All EWIS components used for bonding and protection against static electricity play a vital role in ensuring the integrity of the bonds. 2 CS 25.1715(a) requires that EWIS used for electrical bonding and protection against static electricity meet the requirements of CS 25.899. To minimise the hazardous effects of static discharge, EWIS components should be selected, designed, and installed so that the cross-sectional area of bonding paths used for primary and secondary bonding ensure that an appropriately low electrical impedance is obtained and maintained throughout the expected service life of the components. The maximum resistance for electrical bonds varies depending on the type of bond, e.g., ground stud, between connector shell and structure. 3 CS 25.1715(b) requires that EWIS components used for any electrical bonding purposes (not just those used for protection against static electricity) provide an adequate electrical return path under both normal and fault conditions. EWIS components should be selected, designed, and installed so that the cross-sectional area of bonding paths used for primary and secondary bonding paths ensure that appropriately low electrical impedance is obtained and maintained throughout the expected service life of the components.
[Amdt 25/5]