Modern jet fighters operate at high speed with complicated maneuvers, and the induced severe G forces (G-loc) are the leading risk that causes pilots' physical damage and fatigue. Through in-depth interviews with Air Force jet pilots in Taiwan, Republic of China (ROCAF), the current study aims to classify and understand body fatigue under combat maneuvers due to G forces. Summaries from interviewed data and suggestions to improve pilots' operating fatigue and prevent body damage are provided to reduce flight accidents.