This paper provides an indepth examination of the concept of pilot situational awareness. A detailed definition of the concept is provided, examining both the components that make up situational awareness and its dynamic aspects. We then describe what we consider to be the benefits of enhanced situational awareness. These include: improved safety, reduced workload, enhanced pilot performance, expanded range of pilot operations, and improved decisionmaking. The question of measurement is next considered. Both the direct measurement of situational awareness and the measurement of pilot performance are addressed. The paper ends with a discussion of methods for enhancing situational awareness.