when it changes state from a liquid to a gas. This may result in the air dropping below freezing, causing water vapor contained in the air to first change state from a gas to a liquid, which then becomes ice. This ice forms on the throttle plate, which is located "down stream" of the fuel nozzle. The ice also forms on the inner walls of the carburetor, sometimes to such a degree that it blocks airflow to the engine. Float type carburetors work best when in a stable operating condition. General aviation aircraft operate in a range of conditions not much different from that of an automobile, so a float type carburetor may be all that is needed. Large or fast aircraft are a different matter, especially when considering that fighter aircraft may fly inverted, or through a series of high g turns, climbs and dives, all at a wide range of speeds and altitudes, and in a very short time. Once the carburetor leaves a stable condition, the float is influenced by both gravity and inertia, resulting in inaccurate fuel metering and a reduction in engine performance as the air-fuel ratio changes, becoming either too lean or too rich for maximum engine performance, and in some cases, stopping the engine. Float type carburetors are able to compensate for these unstable conditions through various design features, but only within reason. For example, once the float type carburetor is under negative g conditions, such as a rapid nose down attitude, the float lifts toward the top of the fuel bowl as the float becomes weightless when the aircraft descends faster than the float and the fuel. The float is lifted upward by inertia, closing the fuel inlet valve as if the fuel bowl was full of fuel. Cutting off the fuel supply causes the fuel-air ratio to become greater than sixteen to one, which is then too lean for combustion to take place, stopping the engine. The inverse is also true when the aircraft is in inverted flight. The float becomes submerged as the fuel is pulled downward by gravity to the top of the fuel bowl. The float lifts upward toward the bottom of the inverted fuel bowl. With the float at the bottom of the fuel bowl, the fuel inlet valve opens, as it would when there is not enough fuel in the fuel bowl. With the fuel inlet