Page 109 - ภาษาอังกฤษสำหรับสายวิทยาการอุตุนิยมวิทยา

104

8. Ground Icing

Water on the airport surface is thrown up on the aircraft as the aircraft moves on the ground;
just as water is thrown up on cars driving on wet roads. If the temperatures are below
freezing, this water may form ice on the exposed surfaces of the aircraft and prevent correct
operation of the various mechanical parts, such as the equipment that raises and lowers the
wheels, the brakes, etc.
9. Induction System Icing

Induction system icing is caused when the gasoline is changed to a vapor and mixed with the
air entering the engine. The vaporization of the gasoline combined with the expansion of the
air as it passes through the carburetor causes a rapid cooling of the mixture. The
temperature of the air passing through the carburetor may fall as much as 60'F in a fraction
of a second. The water vapor in the air is forced out of the air by this cooling, and if the
temperature in the carburetor is O'C or below, the moisture wil1 form as frost or ice inside
the carburetor. Even a slight accumulation of carburetor ice will reduce power and may lead
to complete stopping of the engine if the accumulation is allowed to continue.