AERONAUTICAL GLOSSARY : ALTIMETER - ATTITUDE INDICATOR

ALTIMETER—A flight instrument that indicates altitude by sensing pressure changes.

ALTITUDE ENGINE—A reciprocating aircraft engine having a rated takeoff power that is predictable from sea level to an established higher altitude.

AMBIENT PRESSURE—The pressure in the area immediately surrounding the aircraft.

AMBIENT TEMPERATURE—The temperature in the area immediately surrounding the aircraft.

ANEROID—A sealed flexible container that expands or contracts in relation to the surrounding air pressure. It is used in an altimeter or a barometer to measure the pressure of the air.

ANGLE OF ATTACK—The acute angle between the chord line of the airfoil and the direction of the relative wind. It is important in the production of lift.

ANGLE OF INCIDENCE—The angle formed by the chord line of the wing and a line parallel to the longitudinal axis of the airplane.

ANHEDRAL—A downward slant from root to tip of an aircraft's wing or horizontal tail surface.

ANNUAL INSPECTION—A complete inspection of an aircraft and engine, required by the Code of Federal Regulations, to be accomplished every 12 calendar months on all certificated aircraft. Only an A&P technician holding an Inspection Authorization can conduct an annual inspection.

ANTISERVO TAB—An adjustable tab attached to the trailing edge of a stabilator that moves in the same direction as the primary control. It is used to make the stabilator less sensitive.

AREA FORECAST (FA)—A report that gives a picture of clouds, general weather conditions, and visual meteorological conditions (VMC) expected over a large area encompassing several states.

AREA NAVIGATION (RNAV)—A system that provides enhanced navigational capability to the pilot. RNAV equipment can compute the airplane position, actual track and groundspeed and then provide meaningful information relative to a route of flight selected by the pilot. Typical equipment will provide the pilot with distance, time, bearing and crosstrack error relative to the selected "TO" or "active" waypoint and the selected route. Several distinctly different navigational systems with different navigational performance characteristics are capable of providing area navigational functions. Present day RNAV includes INS, LORAN, VOR/DME, and GPS systems.

ARM—The horizontal distance in inches from the reference datum line to the center of gravity of an item. The algebraic sign is plus (+) if measured aft of the datum, and minus (-) if measured forward of the datum.

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

ASYMMETRIC THRUST—Also known as P-factor. A tendency for an aircraft to yaw to the left due to the descending propeller blade on the right producing more thrust than the ascending blade on the left. This occurs when the aircraft's longitudinal axis is in a climbing attitude in relation to the relative wind. The Pfactor would be to the right if the aircraft had a counterclockwise rotating propeller.

ATTITUDE—A personal motivational predisposition to respond to persons, situations, or events in a given manner that can, nevertheless, be changed or modified through training as sort of a mental shortcut to decision making.

ATTITUDE INDICATOR — An instrument that uses an artificial horizon and miniature airplane to depict the position of the airplane in relation to the true horizon. The attitude indicator senses roll as well as pitch, which is the up and down movement of the airplane's nose.