• Above Ground Level (AGL) - The measurement of the height of an obstacle above the ground. A 250’ radio tower is 250’ AGL. See also MSL.
  • Amphibious Aircraft – a class of aircraft that can land both on land or water.
  • Ballistic Recovery System – A parachute attached to the airframe that, once deployed by the pilot, can lower the entire airframe to the ground.
  • Calibrated Air Speed (CAS) - The indicated air speed of an aircraft, corrected for position and instrument error. CAS is equal to true air speed in standard atmosphere at sea level. See also TRUE AIR SPEED and INDICATED AIR SPEED.
  • Composite – Composite is a generic term used to refer to the airframe construction technique of combining various materials to create a new material. In aircraft construction, the composites are usually fiberglass or carbon fiber, both of which combine a type of cloth fabric with resin and a curing process.
  • Constant Speed Propeller – A propeller that relies upon a governor mechanism to adjust the blade pitch to maintain a constant engine speed during all phases of flight. The pitch can be controlled by the pilot in flight using a level located by the throttle lever.
  • Fixed Landing Gear – Permanently affixed to the aircraft in the down position, not retractable.
  • Fixed Pitch Propeller – Propeller blade pitch is not adjustable in flight. However, some LSA propellers may be ground adjustable to alter performance but the adjustment must be fixed in place after altering pitch.
  • Full Fuel Payload – The amount of weight that the aircraft can carry with a full fuel load. This weight is calculated by subtracting the weight of the fuel load (useable fuel quantity x 6 lbs/gal) from the published useful load. The weight of pilot, passengers and luggage cannot exceed the full fuel payload capacity.
  • Glass Cockpit – A slang term used to describe a new genre of flat panel computerized flight instruments that replace tradition gauges. See also SIX PACK.
  • Ground Speed - The actual speed that an aircraft travels over the ground that combines the aircraft's powered speed and the wind speed relative to the aircraft's direction of flight. A tailwind can increase the aircraft speed over the ground faster that it’s true air speed while a strong headwind may result in a slower ground speed than the aircraft true airspeed.
  • Indicated Air Speed (IAS) - A direct instrument reading obtained from an air speed indicator uncorrected for altitude, temperature, atmospheric density, or instrument error. Since air becomes less dense as altitude increases, an air speed indicator loses accuracy so the indicated airspeed is what the pilot sees on the instrument although the aircraft will be traveling at a higher true air speed. See also TRUE AIR SPEED and CALIBRATED AIR SPEED.
  • Knot - One nautical mile is 15% greater than a statue mile (6,080'); a Light Sport Aircraft flying at 120 knots is traveling at 138 mph.
  • Instrument Flight Rules (IFR) – Regulations that govern flight in instrument meteorological conditions or when the lack of visibility prevents flying by ground reference so the pilot must aviate and navigate solely by referencing the aircraft instruments.
  • Instrument Meteorological Conditions (IMC) - Meteorological conditions expressed in terms of visibility, distance from clouds, and ceiling less than the minimums for visual meteorological conditions (VMC).
  • Max Gross Weight – The maximum gross weight of the aircraft is the greatest weight that the aircraft has been certified to where it is compliant with the certification envelope.
  • Mean Sea Level (MSL) - The average height of the surface of the sea for all stages of tide; used as a reference for elevations. An aircraft flying at 6,000’ feet is 6,000’ MSL. The peak of a 10,000’ mountain is 10,000 MSL. See also AGL.
  • Sea Plane – A water-based aircraft (also known as a flying boat) has a fuselage that is actually a hull for landing on water rather than the pontoons of a floatplane.
  • Six Pack – This is a slang term used to describe the tradition primary flight instruments (also referred to as “steam gauges”) typically configured in two rows of three gauges (attitude indicator, altimeter, airspeed indicator, vertical speed indicator, directional gyro and turn coordinator.)
  • Stall - A loss of lift when the angle of attack increases to a point where the flow of air breaks away from a wing or airfoil, causing the wing to drop.
  • Stall Speed – The speed at which an aircraft wing ceases to generate adequate lift to keep the aircraft flying.
  • Standard Empty Weight – When an aircraft is certified, it is weighed with all of the equipment installed (without fuel). This becomes the standard empty weight for that specific aircraft. To calculate Useful Load, subtract the Standard Empty Weight from the Maximum Gross Weight.
  • True Air Speed (TAS) – The speed at which an aircraft is traveling through the air. However, since air speed indicators only indicate true air speed only under standard sea-level conditions, true air speed is usually calculated by adjusting an Indicated Air Speed (IAS) according to temperature, density, and pressure. See also INDICATED AIR SPEED and CALIBRATED AIR SPEED
  • Useful Load – Represents amount of weight that an aircraft is certified to carry. The weight of the amount of fuel on board, pilot, passengers and luggage must not exceed the published useful load of the aircraft.
  • Visual Flight Rules (VFR) – Regulations that govern the procedures for conducting flight under visual conditions when the ground can be referenced or above a cloud layer in clear sky.
  • Visual Meteorological Conditions (VMC) - Meteorological conditions expressed in terms of visibility, distance from clouds, and ceiling equal to or better than specified minimums.
  • Vso – Aircraft are certified with a variety of critical speeds generically referred to as “V speeds” that tell the pilot the best glide speed, speed to achieve the best rate of climb, the stall speed, minimum controllable speed, never exceed speed, maneuvering speed, and many other. Vso lists the speed for the aircraft speed in its landing configuration (i.e., flaps extended and gear extended).