Aircraft Wires and Cables Installation

Aircraft wires inspection.

Inspection of wiring and cable integrity should be done by inspecting interconnecting wiring, aircraft cables installation, and conduit between various pieces of electronic equipment to determine that they do not rub against the airframe or each other under vibration conditions encountered in flight. Inspect open wiring and cabling for fraying, damage or distortion resulting from heavy objects being placed on them, being stepped on, or being used as handholds.

PROTECT FROM FLUIDS. Separate aircraft wires or cables from flammable fluids lines or those which carry fluids which have a deteriorating effect on wire insulation. Wiring or cables should be routed above such lines and securely clamped to the aircraft structure. An arcing fault between an electric cable and a fluid line may puncture the line and result in a fire.

Aircraft wiring replacement.

WIRE AND CABLE CLAMPS. Inspect aircraft wire and cable clamps for proper tightness. Where cables pass through structure or bulkheads, inspect for proper clamping or grommets. Inspect for sufficient slack between the last clamp and the electronic equipment to prevent strain at the cable terminals and minimize adverse effects on shock mounted equipment.

CONDUIT. Conduit is manufactured in metallic and nonmetallic materials and in both rigid and flexible forms. Primarily its purpose is for mechanical protection of the cable within. Inspect conduit for proper end fittings, absence of abrasion at the end fittings, and proper clamping. Inspect for distortion, adequate drain points which are free of dirt, grease, or other obstructions, and freedom from abrasion or damage due to moving objects such as aircraft control cables or shifting cargo.

PLASTIC WIRE SLEEVING. Inspect plastic wire sleeving for damage due to abrasion, solvents, or hydraulic fluids.

ELECTRICAL TAPE. The chemical base of most plastic electrical tape is polyvinylchloride (PVC). This tape is not flame resistant unless it is specially processed to make it so. Some manufacturers are producing flame-resistant PVC tape and have obtained Fire Underwriter's Laboratory (UL) approval which is shown on the wrapping of the container. Unless the tape shows such approval, it should not be used until its flame resistance properties have been determined. A simple test can be made by applying a flame to a sample of unknown tape and comparing its burning qualities to a sample of flame-resistant tape.

High temperature fire resistant cable

Flame resistant or not, PVC will decompose at temperatures above 221* F. (105° C.) with rapid loss of insulating qualities. It is not recommended for use in compartments where temperatures normally approach 221° F. (105° C.) nor in designated fire zones unless precautions are taken to prevent short circuits to the airframe, shielded wires in bundles, or any other electrical ground, in the event of decomposition. Of course, high temperature fire resistant cable should be used wherever possible.

Source by John Routledge

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