The aircraft tank and gauge system of the present invention provides a fuel tank with a gauge chamber located generally aligned with the tank center of gravity and that has a general vertical orientation when the aircraft is level. The gauge chamber extends from the top of the tank to a height generally equivalent to a high collection point on the tank and/or extends from the bottom of the tank to a height generally equivalent to a low collection point on the tank. As the aircraft pitches and rolls, fuel within a complex-shaped tank, will be measured by a sensor in the gauge chamber. In order to prevent any type of vapor blockage in the gauge chamber, a first vent extends from the bottom of the gauge chamber to the low collection point of the tank and a second vent extends from the top of the gauge chamber to the high collection point of the tank.