INTERFERENCE DRAG—Type of drag produced by placing two objects adjacent to one another. Combines the effects of form drag and skin friction. 

INVERSION—An increase in temperature with altitude. 

JUDGMENT—The mental process of recognizing and analyzing all pertinent information in a par- ticular situation, a rational evaluation of alternative actions in response to it, and a timely decision on which action to take. 

KINESTHESIA—The sensing of movements by feel. 

KITE—To pressurize and raise the wing overhead the PPC cart. 

KITING—Taxiing the PPC on the ground with the wing inflated and overhead. 

KNOWLEDGE EXAM—See FAA KNOWLEDGE EXAM. 

LATERAL AXIS—An imaginary line passing through the center of gravity of a PPC and extend- ing across the PPC from one side of the aircraft to the other side. 

LEADING EDGE—The part of an airfoil that meets the airflow first. 

LIFT—One of the four main forces acting on an aircraft. On a powered parachute, an upward force created by the effect of airflow as it passes over and under the wing. 

LIGHT-SPORT AIRCRAFT (LSA)—An aircraft that meets the requirements defined in 14 CFR 1.1, regardless of airworthiness certification. 

LINE-OVERS—A dangerous situation when the suspension line goes over the top of the wing instead of going straight from the wing to the riser system. This condition will prevent proper infla- tion of the wing. 

LINE TWISTS—When the PPC suspension lines on both sides of the wing are spiraled together. Flying with a line twist is unsafe; the wing is unairworthy until it is corrected. 

LOC—A preflight check: L – Lines Free, O – Cells Open, C – Wing Centered. 

LOGBOOK—A record of activities: flight, instruc- tion, inspection and maintenance. Reference 14 CFR 43, 14 CFR 61.51, and 14 CFR 91.417. 

LONGITUDINAL AXIS—An imaginary line through an aircraft from nose to tail, passing through its center of gravity. The longitudinal axis is also called the roll axis of the aircraft. 

LSA—See LIGHT-SPORT AIRCRAFT. 

MAC—See MEAN AERODYNAMIC CHORD. 

MAGNETO—A self-contained engine-driven unit that supplies electrical current to the spark plugs. 

MAKE/MODEL—Refers to the manufacturer and model of a specific aircraft. 

MANEUVERING ALTITUDE—An altitude above the ground that allows a sufficient margin of height to permit safe maneuvering. 

MAXIMUM GROSS WEIGHT—The maximum au- thorized weight of the aircraft and all of its equip- ment as specified in the TCDS for the aircraft. 

MEAN AERODYNAMIC CHORD (MAC)—The average distance from the leading edge to the trail- ing edge of the wing. 

MECHANICAL TURBULENCE—Type of tur- bulence caused by obstructions on the ground interfering with smooth flow of the wind. Trees, buildings and terrain can all cause mechanical turbulence. 

MEDICAL CERTIFICATE—Acceptable evidence of physical fitness on a form prescribed by the Administrator. 

MEDIUM-BANKED TURN—Turn resulting from a degree of bank (approximately 20 to 45 degrees) at which the PPC remains at a constant bank. 

MILITARY TRAINING ROUTES (MTR)—Special routes developed to allow the military to conduct low-altitude, high speed training. 

MILITARY OPERATIONS AREA (MOA)—Air- space of defined vertical and lateral limits es- tablished for the purpose of separating certain military training activity from IFR traffic. 

MINDSET—A factor in aeronautical decision making where decision making is influenced by preconceived ideas about the outcome of events. For example, an expectation of improving weather conditions can lead to increased risk during a flight. 

MOA—See MILITARY OPERATIONS AREA. 

MODE C TRANSPONDER—A receiver/transmit- ter which will generate a radar reply signal upon proper interrogation; the interrogation and reply being on different frequencies. Mode C means the reply signal includes altitude information. 

MOMENT— A force that causes or tries to cause an object to rotate. The product of the weight of an item multiplied by its arm. Moments are expressed in pound-inches (lb-in). Total moment is the weight of the PPC multiplied by the distance between the datum and the CG. 

NEWTON’S THIRD LAW OF MOTION—When- ever one body exerts a force on another, the sec- 

