Since cables are used in pairs and are stretched taut, very little play is present in system controls, and no lost motion exists between the actuating device and the unit. Consequently, cable-controlled units respond quickly and accurately to cockpit control movement. In some simple cable systems, only one cable is used, and a spring provides the return action. Aileron throw protractor indications. Cables must be kept clean and inspected periodically for broken wires, corrosion, kinking, and excessive wear.
Broken wires are most apt to occur in lengths of cable that pass over pulleys or through fairleads.
On certain periodic inspections, cables are checked for broken wires by passing a cloth along the length of the cable. Where the cloth snags the cable is an indication of one or more broken wires. Using your bare hands to check for broken wires could result in personal injury. Tests have proven that control cables may have broken wires and still be capable of carrying their designated load. A maximum of three broken wires per inch is allowable in the length of cables passing over pulleys, drums, or through fairleads.