Control Cables
Core concepts
Aircraft control cables are preformed, stranded constructions - mainly 7x7 (stiffer, more abrasion resistant) and 7x19 (more flexible, used round small pulleys). Terminals are swaged (Nicopress type), spliced, ball-ended or threaded, and each has its own proof load and inspection criteria. Turnbuckles provide rigging adjustment, with locking clips and safety wire, and a specified minimum thread engagement in the barrel.
Rigging tension is measured with a tensiometer and corrected to the reference temperature in the maintenance manual. Cables contract as they cool, so tension rises in a cold soak and falls when hot - a cable rigged correctly in a warm hangar can be dangerously tight at altitude in winter. Pulleys must be the correct size and in line, fairleads and pressure seals must not chafe, and the cable must not rub on structure.
Traps in questions
Turnbuckle terminals must never be backed out so far that the inspection hole is uncovered. Never solder a structural cable terminal. Broken-wire limits apply per strand and over a stated length - and corrosion inside a swaged terminal is a frequent hidden failure. Bird-caging means the strands have opened and the cable is unserviceable. Cables must not be used to spring components into alignment.
Rule of thumb
Inspect at every pulley, fairlead and terminal, check tension at the reference temperature, and replace any cable with a bird-caged, kinked or corroded section.