Using a magnet to determine if a cable is galvanized steel or stainless steel alloy can be unreliable as stainless steel can display magnetic properties which can make alloy discrimination difficult. The unreliability comes from variation in the amount of magnetic permeability found in the stainless steel cable and from strength differences in the magnets used. Stainless steel cables become magnetic in the process of cold working stainless steel wires into cable. The amount of magnetic permeability varies with the amount of cold working the cable was subject to. It is also possible cables in-service will become more magnetic over time as the work harden through use.
A better test is to use an ohm meter to measure the resistance in a length of cable. Stainless steel has more electrical resistance than zinc or tin coated high carbon steel, which allows us to identify cable composition by the amount of resistance in a length of cable. This test is applicable to the most common aircraft cable diameters: 1/16 through 5/32 with 7x7 or 7x19 construction. To ensure accuracy in cable resistance measurements, use the following procedure:
If the cable is to be returned to service, reinstall and rig the cable as per the aircraft manufacturer's service manual. Install all required safety devices.
To find the correct cable for your aircraft, go to Flight Control Cables and Chains.