AOA—See ANGLE OF ATTACK. 

ARM—The horizontal distance in inches from the reference datum line to the center of gravity of an item. Used in weight and loading calculations. 

AROW— The mnemonic aid to remember the certificates and documents required to be onboard an aircraft to determine airworthiness: Airworthi- ness certificate, Registration certificate, Operating limitations, Weight and balance data. 

ASOS—See AUTOMATED SURFACE OBSERV- ING SYSTEM. 

ASPECT RATIO—Span of a wing divided by its average chord. 

ASYMMETRICAL AIRFOIL—An airfoil section that is not the same on both sides of the chord line. 

ATIS—See AUTOMATIC TERMINAL INFORMA- TION SERVICE. 

AUTOMATED SURFACE OBSERVING SYS- TEM (ASOS)—Weather reporting system which provides surface observations every minute via digitized voice broadcasts and printed reports. 

AUTOMATED WEATHER OBSERVING SYSTEM (AWOS)—Automated weather reporting system consisting of various sensors, a processor, a com- puter-generated voice subsystem, and a transmitter to broadcast weather data. 

AUTOMATIC TERMINAL INFORMATION SER- VICE (ATIS)—The continuous broadcast (by ra- dio or telephone) of recorded noncontrol, essential but routine, information in selected terminal areas. 

AVIATION MEDICAL EXAMINER (AME)—A medical doctor authorized to perform aviation medical exams for aviators. 

BANK ATTITUDE—The angle of the lateral axis relative to the horizon. 

BASE LEG—A flight path at right angles to the landing runway off its approach end. The base leg normally extends from the downwind leg to the intersection of the extended runway centerline. 

CAMBER—The curvature of a wing when look- ing at a cross section. A wing has upper camber on its top surface and lower camber on its bottom surface. 

CANOPY—The fabric body of a parachute. 

CARBURETOR ICE—Ice that forms inside the car- buretor 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. 

CART—The engine and seats, attached by a struc- ture to wheels; sometimes referred to as the fuse- lage, cockpit, chaise, or airframe. 

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 PPC 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 pro- duced by the airfoil are considered to be concen- trated. 

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 cen- trifugal force. 

CERTIFICATED FLIGHT INSTRUCTOR (CFI)— A flight instructor authorized by the FAA to provide flight instruction in designated category of aircraft. 

CFI—See CERTIFIED FLIGHT INSTRUCTOR. 

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. 

CLASS A AIRSPACE—Airspace from 18,000 feet MSL up to and including FL600, including the airspace overlying the waters within 12 NM of the 

