Operator performance in non-destructive testing: A study of operator performance in a performance test

In the process industries there is a need of inspecting the integrity of critical components without disrupting the process. Such in-service inspections are typically performed with non-destructive testing (NDT). In NDT the task of the operator is to (based on diagnostic information) decide if the component can remain in service or not. The present study looks at the performance in NDT. The aim is to improve performance, in the long run, by exploring the operators' decision strategies and other underlying factors and to this way find out what makes some operators more successful than others. Sixteen operators performed manual ultrasonic inspections of four test pieces with the aim to detect (implanted) cracks. In addition to these performance demonstration tests (PDT), the operators performed independent ability tests and filled out questionnaires. The results show that operators who trust their gut feeling more than the procedure (when the two come to different results) and that at the same time have a positive attitude towards the procedure have a higher PDT performance. These results indicate the need for operators to be motivated and confident when performing NDT. It was also found that the operators who performed better rated more decision criteria higher in the detection phase than the operators who performed worse. For characterizing it was the other way around. Also, the operators who performed better used more time, both detecting and characterizing, than the operators who performed worse