“Red plague” is the galvanic corrosion of silver coated copper conductors that occurs at exposed copper locations.  Liquid water introduced via direct contact or condensation provides the medium for ion transport driven by the substantial silver/copper electro-potential difference.  Copper, the primary conductor material, is the sacrificial anode in this configuration.  It is difficult to predict the extent of copper corrosion that will be achieved over time because water is not consumed by reaction, and the corrosion continues under the silver coating.

Occurrences of red plague have periodically affected aerospace and defense programs for more than 40 years.  Wire and cable industry process improvements have not eliminated the problem.  Recent identification of red plague affecting a Missile Defense Industry (MDA) program and a Navy program has refocused Department of Defense attention on corrosion control for silver coated copper wire.  An MDA Advisory specifically about this matter has been released.  It is deemed essential that appropriate solutions be developed and implemented to ensure mission success. 

The US Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC) and Raytheon Missile Systems (RMS) are developing long and short term solutions.  Imposition of storage and handling conditions intended to prevent water intrusion, combined with material age controls and stripped back material inspections are near term solutions being pursued.  Empirical evidence collected by RMS indicates that red plague resistance is improved by increasing the silver coating thickness and requiring a cross section measurement for lot acceptance.  Changes to the applicable specification documents will be pursued based on presentation of this evidence.