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Wire bundle breakout joints;

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Missing or broken bonding jumper cables;

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Sharp bend radius causing mechanical strain;

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Localized heat damage;

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Fluid stains;

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Missing or damaged heat or drip shields;

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Absence of drip loops;

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Loss of wire segregation;

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Broken, missing and incorrect sized clamps andmissing ties;

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Missing sleeving and grommets and damage wherewires enter or exit a metal conduit;

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Chafing of wires on structure, particularly intransition zones such as engine nacelle to fuselage, fuselage to wing and fuselage to wheel well etc.;

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Damage to and contamination of wiring caused bymaintenance activity or by cargo and baggage handling; and

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Presence of combustible material including lint,paper and fluid residue.

The benefits of a clean wiring system are applicable to all sizes of aircraft, whether it be the largest multi-engine transport category or the smallest single engine general aviation category aircraft. The difference is that the task is much easier and less labour intensive for the latter category of aircraft.
CLEANLINESS IS NEXT TO…
In an initial step towards addressing wiring systems, the concept of "Clean As You Go" is being promoted. This means that before any planned maintenance action is started, the area affected should be inspected and any wiring in the area should be protected to ensure it does not become damaged or contaminated by the planned work. If electrical connectors have to be removed to facilitate access, they should be blanked-off. After completing the work, the area should be thoroughly cleaned. A video, titled “ATA Specification 117 - Wiring Maintenance Practices/Guidelines”, has been produced illustrating the guidelines to follow when performing maintenance in the vicinity of aircraft wiring.
AN EVOLVING INSPECTION CULTURE
A cultural change such as the "Clean As You Go" concept can be implemented and the benefits enjoyed today; it is not necessary to wait for regulatory action to address concerns with wiring systems. Furthermore, the regulatory actions likely would not be applicable, at least initially, to the smaller aircraft fleets.
It is recognized that there are limits on what can be achieved through wire inspections. The next feed
article will discuss how damaged and age-deteriorated wire can lead to in-service difficulties or worse.
Photos: Courtesy of J.R. (Rod) Digney
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本文鏈接地址：加拿大航空服務難度報告 Canadian Aviation Service Difficulty Reports(10)