A thermal management system is provided for incorporation into a gas turbine engine, wherein the gas turbine engine, the aircraft, or both define a vertical direction. The thermal management system including: a thermal transport bus having a thermal fluid flowing therethrough; a plurality of heat source exchangers in thermal communication with the thermal fluid in the thermal transport bus; and a pump assembly in flow communication with the thermal transport bus, the pump assembly including: a pump; and a pump protection device positioned below the pump along the vertical direction.