Abstract: Taking the complex fire environment of high-rise buildings as the research background, this study investigates the attitude response of a tethered UAV firefighting hose—referred to hereafter as the "flexible pipe cable"—during long-distance vertical transport under multi-source perturbation conditions. The research thoroughly considers the dynamic posture characteristics of the flexible pipe cable under varying environmental wind speeds and the offset distances between the fire truck end and the drone's jet end of the cable. Based on OrcaFlex software, a 200 m vertical transport model of the flexible pipe cable was developed, focusing on analyzing its attitude response, offset degree, and along the pipe cable tension distribution. The results show that in the quasi-steady state, as the wind speed increases, the degree of offset in comparison with that in the initial state is intensified, the length of the touchdown length of the pipe cable and the time to reach the quasi-steady state decrease, the amount of offset increases, and the offset angle of the B-end of the pipe cable increases. Tension increases gradually from the fire truck end along the pipe cable and peaks at the UAV spray end, with a positive correlation between along-pipe cable tension and wind speed. As the offset distance increases, the degree of offset is smaller than that in the initial state, the horizontal offset increases, and the offset angle at the B-end of the pipe cable decreases; there is a positive correlation between along-pipe cable tension and displacement distance. Ultimately, the relationship between the tension at the jet end of the pipe and the cable UAV and the wind speed at different offset distances was established, and the critical wind speed for tethered UAVs firefighting safety operations was obtained, which provides a theoretical basis and data basis for the application of tethered UAVs in firefighting operations.