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 breakers  differs from a fuse in that it can be reset without having to  be replaced.  Cambered.  The camber of an airfoil is the characteristic  curve of its upper and lower surfaces. The upper camber is  more pronounced, while the lower camber is comparatively  flat. This causes the velocity of the airflow immediately  above the wing to be much higher than that below the wing.  Clear air turbulence.  Turbulence not associated with any  visible moisture.  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.  Climb gradient.  The ratio between distance traveled and  altitude gained.  Cockpit resource management.  Techniques designed to  reduce pilot errors and manage errors that do occur utilizing  cockpit human resources. The assumption is that errors  are going to happen in a complex system with error-prone  humans.  Carburetor.  1. Pressure: A hydromechanical device  employing a closed feed system from the fuel pump to the  discharge nozzle. It meters fuel through fixed jets according  to the mass airflow through the throttle body and discharges  it under a positive pressure. Pressure carburetors are  distinctly different from float-type carburetors, as they do not  incorporate a vented float chamber or suction pickup from  a discharge nozzle located in the venturi tube. 2. Float-type:  Consists essentially of a main air passage through which the  engine draws its supply of air, a mechanism to control the  quantity of fuel discharged in relation to the flow of air, and a  means of regulating the quantity of fuel/air mixture delivered  to the engine cylinders.  Coefficient of lift.  See lift coefficient.  Coffin corner.  The flight regime where any increase in  airspeed will induce high speed Mach buffet and any decrease  in airspeed will induce low speed Mach buffet.  Cascade reverser.  A thrust reverser normally found on  turbofan engines in which a blocker door and a series of  cascade vanes are used to redirect exhaust gases in a forward  direction.  Combustion chamber.  The section of the engine into which  fuel is injected and burned.  Common traffic advisory frequency.  The common  frequency used by airport traffic to announce position reports  in the vicinity of the airport.  Center of gravity (CG).  The point at which an airplane  would balance if it were possible to suspend it at that point.  It is the mass center of the airplane, or the theoretical point  at which the entire weight of the airplane 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 airplane.  Complex aircraft.  An aircraft with retractable landing  gear, flaps, and a controllable-pitch propeller, or is turbine  powered.  Compression ratio.  1. In a reciprocating engine, the ratio  of the volume of an engine cylinder with the piston at the  bottom center to the volume with the piston at top center. 2.  In a turbine engine, the ratio of the pressure of the air at the  discharge to the pressure of air at the inlet.  Center-of-gravity limits.  The specified forward and aft  points within which the CG must be located during flight.  These limits are indicated on pertinent airplane specifications.  Center-of-gravity range.  The distance between the  forward and aft CG limits indicated on pertinent airplane  specifications.  Centrifugal flow compressor.  An impeller-shaped device  that receives air at its center and slings air outward at high  velocity into a diffuser for increased pressure. Also referred  to as a radial outflow compressor.  Compressor bleed air.  See bleed air.  Compressor bleed valves.  See bleed valve.  Compressor section.  The section of a turbine engine that  increases the pressure and density of the air flowing through  the engine.   G-4