means of regulating the quantity of fuel/air mixture delivered to the engine cylinders. 

Carburetor ice.  Ice that forms inside the carburetor due to the temperature drop caused by the vaporization of the fuel. Induction system icing is an operational hazard because it can cut off the flow of the fuel/air charge or vary the fuel/air ratio. 

Carriage. The engine and seats, attached by a structure to wheels; sometimes referred to as the fuselage, cockpit, chaise, or airframe. 

Carriage keel. The lower center tube in the carriage that runs fore and aft which connects the mast to the front tube. 

CAS.  See calibrated airspeed. 

Cavitation. A condition that exists in a fluid pump when there is not enough pressure in the reservoir to force fluid to the inlet of the pump. The pump picks up air instead of fluid. 

Center of gravity (CG).  The point at which an aircraft would balance if it were possible to suspend it at that point. It is the mass center of the aircraft, or the theoretical point at which the entire weight of the WSC is assumed to be concentrated. It may be expressed in inches from the reference datum, or in percent of mean aerodynamic chord (MAC). The location depends on the distribution of weight in the aircraft. 

Center of lift. The location along the chord line of an airfoil at which all the lift forces produced by the airfoil are considered to be concentrated. 

Center of pressure (CP). The point along the wing chord line where lift is considered to be concentrated. 

Centrifugal force.  The apparent force occurring in curvilinear motion acting to deflect objects outward from the axis of rotation. For instance, when pulling out of a dive, it is the force pushing you down in your seat. 

Centripetal force.  The force in curvilinear motion acting toward the axis of rotation. For instance, when pulling out of a dive, it is the force that the seat exerts on the pilot to offset the centrifugal force. 

Certificated Flight Instructor (CFI). A flight instructor authorized by the FAA to provide flight instruction in designated category of aircraft. 

Certified Flight Instructor with a Sport Pilot Rating (CFIS).  A flight instructor authorized by the FAA to provide flight instruction in designated category of aircraft for sport pilots only. 

CFI.  See Certified Flight Instructor. 

CFIS.  See Certified Flight Instructor with a Sport Pilot Rating. 

CFR. See Code of Federal Regulations. 

CG. See center of gravity. 

Checklist.  A list of procedures that provides a logical and standardized method to operate a particular make and model aircraft. 

Checkride.  A practical test administered by an FAA examiner or designated examiner for the purpose of issuing an FAA certificate or rating. 

Chord line.  An imaginary straight line drawn through an airfoil from the leading edge to the trailing edge. 

Circuit breaker.  A circuit-protecting device that opens the circuit in case of excess current flow. A circuit breaker differs from a fuse in that it can be reset without having to be replaced. 

C$_{L}$.  See coefficient of lift. 

Class A Airspace.  Airspace from 18,000 feet MSL up to and including FL 600, including the airspace overlying the waters within 12 NM of the coast of the 48 contiguous states and Alaska; and designated international airspace beyond 12 NM of the coast of the 48 contiguous states and Alaska within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic procedures are applied. 

Class B Airspace.  Airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest airports in terms of IFR operations or passenger numbers. The configuration of each Class B airspace is individually tailored and consists of a surface area and two or more layers, and is designed to contain all published instrument procedures once an aircraft enters the airspace. For all aircraft, an ATC clearance is required to operate in the area, and aircraft so cleared receive separation services within the airspace. 

