Visual Testing (VT)
VT is the most commonly used method of NDT testing because of its ease and cost effectiveness. VT is always performed before any other NDT method is applied because if a discontinuity can be detected visually there may be no need to apply a specialized method that has a higher cost.
The are times were a Technician my have to use the aid of a mirror or magnifying glass in order to perform a thorough examination in areas not easily seen. Some specifications have white light requirements that need to be measured with a light sensor. White light is measured in foot candles or lux and usually range from 50 ftc (500 lux) to 100 ftc ( 100 lux). If the area does not meet the white light requirements the technician may use a flashlight in order to meet the requirement.
VT does also have specialized equipment called borescopes'. Borescopes can be put into places that are not accessible by NDT personnel. They can be used manually and even be attached to a robotic crawler. Some borescopes' can record the examination so that a permanent record is available.