The purpose of rigging and adjusting a primary flight control system is to ensure neutral alignment of all connecting components and to regulate and limit the surface deflection in both directions. Each aircraft has a set of special tools for flight control maintenance that may include rigging fixtures, pins, blocks, throwboards and protractors. Other common equipment, such as micrometers, pressure gauges, push-pull gauges, feeler gauges, tensiometer and calipers may also be required. These arc usually maintained in the toolroom and checked out when needed. The tensiometer is an instrument used in checking cable tension.
Tension is the amount of pulling force applied to the cable.
The amount of tension applied in a cable linkage system is controlled by turnbuckles in the system. A tensiometer is a precision cable tension measuring device, but it has limitations and can be awkward to use. It is inaccurate for cable tension under 30 pounds. When you take tension measurements, the instrument must not be pressed against any part of the aircraft, it can t be pushed or pulled against the cable, and the cable must not be pressed against fairleads or any part of the aircraft. Any one of these actions may lead to inaccurate measurements.