This paper reports on the effects of transient transverse and axial acceleration forces with step changes in input power on the performance of a flexible copper/water arterial heat pipe. Transient transverse accelerations were generated using a centrifuge table to simulate acceleration forces typifying high performance aircraft maneuvering. These transients consisted of step changes, steady periodic, and burst cycles in the transverse acceleration forces. Steady periodic and burst cycle transverse accelerations had frequencies of 0.01 and 0.03 Hz with peak-to-peak values of 1.1 to 9.8 g. Partial depriming of the artery, pooling of the unconstrained working fluid, and fluid sloshing were found to have a significant impact on the heat transport potential and transient behavior of the heat pipe. Repriming of the heat pipe under thermal load while being subjected to transient transverse accelerations was also demonstrated.