The correct tension for a control cable is specified in the Aircraft Maintenance Manual. It is checked using a tensiometer and adjusted using the turnbuckles.
The tensiometer must have the riser installed that is specified for the cable size being checked. The cable is slipped between the riser and the two anvils. The lever is then closed against the housing. The reading on the scale is then applied to a chart to obtain the cable tension. A pointer lock can be used to hold the instrument reading while it is being removed from the cable. The tension is checked when there is no load on the controls and in the middle of the longest stretch of cable between pulley.
Before using the tensiometer make sure that the serial number of the chart is the same as that of the tensiometer. Make sure that the tensiometer is ‘in date’ ie. not due for calibration.
Changes in temperature will affect the tension of the cables and this must be taken into account when adjusting the cable tension. It is usual for a temperature/tension graph to be given by the aircraft manufacturer. Using the graph, the correct tension can be applied to the cable. In colder countries the required load will be lesser as compared to the hotter countries, this is mainly due to temperature effect on materials which causes it to expand or contract.
An example of a graph is shown below.
