This paper describes the flight testing of an 8000 psi Lightweight Hydraulic System. The objective was to reduce weight and space requirements of the hydraulic system in future, high density Navy aircraft. An 8000 psi Lateral Control System was installed in a T-2C (basic Navy trainer) airplane.Four different pilots evaluated the test installation, accumulating a total of 11.5 flight hours. No malfunctions occurred in the 8000 psi system; pilot comments were favorable. Operational characteristics of the 8000 psi system were very similar to the T-2C 3000 psi lateral control system. The test installation performed exceptionally well; fluid temperatures were nominal, pressure fluctuations were small, fluid particulate generation was low, and component endurance was projected to be satisfactory.