Both fuel tanks contained a significant amount of fuel, which investigators calculated to be approximately 100 US gallons in each of the two wing tanks, and the fuel selector valve was in the correct position.
12.
If the erroneous command persisted for more than a predetermined time, differential pressure sensing activated a selector valve to isolate and remove the defective servovalve hydraulic pressure, permitting the remaining channels and servovalves to control the actuator ram spool.
13.
The valves use the pump pressure and the pressure from a centrifugal governor on the output side ( as well as hydraulic signals from the range selector valves and the " throttle valve " or " modulator " ) to control which ratio is selected on the gearset; as the vehicle and engine change speed, the difference between the pressures changes, causing different sets of valves to open and close.
