During standard aircraft maintenance, it occasionally becomes necessary to clean the wiring, remove FOD (foreign object debris), and/or clean equipment near wiring (which is just about everywhere on the aircraft). This process should be handled with care and attention to details.
Cleaning should follow the manufacturer’s recommendations where applicable. Where no information is given on cleaning procedures, the use of a clean natural fiber rag with isopropyl alcohol as the cleaning agent is recommended. Harnesses should be wiped down and never vigorously scrubbed as this may damage the wire insulation. Care should be taken when any maintenance is performed on life systems.
Also, recognition of corrosion in metals is an important part of the EWIS component cleaning process. Because corrosion can have a significant impact on system performance, proactive actions are important.
When cleaning aircraft via pressure washing, one should exercise care to prevent damage to exposed electrical components and EWIS. High pressure sprays can quickly degrade EWIS components such as wire insulation and connectors. Of particular importance are wing leading and trailing edges, wheel wells, and landing gear. When practical, protect EWIS components (for example, wiring and connectors) before pressure washing. If a cleaning solution is used in the spray, it is recommended that the area be rinsed to remove any residue as prolonged exposure can lead to degradation of wire insulations.
If you are interested in best practices for EWIS, you may want to read this article on Life Prediction of EWIS Components.
Cleaning of EWIS requires extreme care and use of proper maintenance procedures to ensure safe and reliable performance. When cleaning an area, avoid movement of the harnesses and/or equipment during cleaning of non-aggressive contamination, such as dust, dirt, or swarf. If the movement of harnesses is necessary for proper cleaning, release wiring from its installation (loosen clamps and ties) in a way that avoids placing stress on the connectors or support devices. Interior wire bundle contamination should be addressed by removing bundle ties before separating wires.