Risk early warning indicators for air traffic controllers' unsafe acts

Abstract The establishment of an early warning indicator system is the foundation and the key to prevent the unsafe acts of air traffic controllers (ATCers). Therefore, the objective of this study is to determine the early warning indicators for controllers' unsafe acts. Data were encoded through grounded theory and HFACS, and the early warning indicator system was designed. The parameter values were calculated by using the data collected from the expert questionnaire survey. Combining the existing safety performance indicators and expert opinions, the measurement and judgment of indicators were clarified. The results show that the early warning indicator system includes four levels: environment, organization, supervision and ATCers. Among the indicators, the mean values of “degree of job skills mastered,” “intensity of working load,” “lack of safety awareness and responsibility” rank the first three. Based on the findings of this study, the unsafe acts of ATCers can be effectively alerted.