MROs: ASIG is Your EWIS Specialist

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March 10, 2011 is a date organizations dedicated to the maintenance, repair, and overhaul (MRO) of transport category aircraft should be aware of it because thereafter they will likely see a growing number of tasks that may now be beyond their core competencies. It is the deadline for operators of these aircraft to incorporate in their maintenance programs OEM-dictated inspections and procedures for electrical wiring interconnection systems (EWIS).

For operators and MROs alike, EWIS is a paradigm shift in thinking. Before its creation 39 months ago, thinking of wiring as a system within a system was an alien concept because it includes everything from cables and harnesses to connectors and clips, ties, mounts, and trays that physically integrate it with the airplane. (For more information, see EWIS Maintenance Program Deadline and EWIS, EZAP & ICA: What’s It all Mean?)

Where MROs may encounter EWIS maintenance program requirements depends on the job, but they stand out in scheduled heavy inspections, especially Cs and Ds. Depending on the operator’s program, it could be a combination of general and detailed visual inspections that seek out moisture or abrasive accumulations of dirt by specific zones, followed by prescribed cleaning procedures and/or repair methods for wiring, connections, and physical integration.

This situation is not unlike the specialization of medicine. Like the family doc, MROs can expertly treat their patients’ everyday structural and circulatory needs. But EWIS is akin to neurology, with a unique set of tools, tooling, and processes. Like family docs, MROs can either invest the time and money needed to add this specialty to their list of capabilities, or they can call in a specialist, which would be ASIG’s FAA Repair Station.

ASIG developed its EWIS maintenance, repair, and overhaul expertise by working with it every day to connect the systems and equipment the company integrates in a variety of aircraft. This capability, supported by a robust and reliable supply chain, makes ASIG responsive, flexible, efficient, and economical. Adding a new task to the repair station’s list of capabilities begins with an internal audits of ASIG’s facilities, tooling, tech data, and personnel.

Rare would be the task beyond its capabilities. It’s dealt everything from fuel quantity systems that require specific impedance to cleaning and repairing the tape-style ribbon harness for the DC-9’s air stair. Usually, the EWIS comes to ASIG, but its technicians will and do travel. And the repair station opens its doors wide to EWIS still affixed in a component, like the wing of a CRJ. Removed for a skin graft, the MRO asked ASIG to make field repairs on several harnesses permanent. A complex undertaking, it required breaking through and restoring the harnesses’ outer braided shielding, which ASIG easily accomplished before returning the wing for re-skinning.

EWIS overhauls can range from new wiring, wire marking, and new connector terminations in all or just a few strands. It all depends on the EWIS requirements, which may only allow a single repair for multiple defects in the wiring instead of three or four fixes. Another example might be environmentally sealed repairs, which might be good once every 10 feet—until it’s overhaul time, when you must replace all affected wires, conduits, shielding, and anti-abrasion devices as specified.

Like any specialist, ASIG maintains, repairs, and overhauls complex wiring systems, major harnesses that run well into five figures. A landing gear harness, for example, can cost $7,000, not counting the time and money to remove and re-install it with the interceding logistics shuffle. A quick engine change harness is another example, and any lead time increases the cost that much more. MROs can contain these costs and reduce them by keeping select EWIS on the shelf as replacements and sending the harness needing treatment to ASIG, which returns it shelf-ready.

Until next time, stay 5x5, mission ready, and Wired!