Glide ratio.  The ratio between distance traveled and altitude  lost during non-powered flight.  Fuel control unit.  The fuel-metering device used on a turbine  engine that meters the proper quantity of fuel to be fed into  the burners of the engine. It integrates the parameters of inlet  air temperature  compressor speed  compressor discharge  pressure  and exhaust gas temperature with the position of  the cockpit power control lever.  Fuel efficiency.  Defined as the amount of fuel used to  produce a specific thrust or horsepower divided by the total  potential power contained in the same amount of fuel.  Fuel heaters.  A radiator-like device which has fuel passing  through the core. A heat exchange occurs to keep the  fuel temperature above the freezing point of water so that  entrained water does not form ice crystals  which could  block fuel flow.  Glidepath.  The path of an aircraft relative to the ground  while approaching a landing.  Global position system (GPS).  A satellite-based radio  positioning  navigation  and time-transfer system.  Go-around.  Terminating a landing approach.  Governing range.  The range of pitch a propeller governor  can control during flight.  Governor.  A control which limits the maximum rotational  speed of a device. Fuel injection.  A fuel metering system used on some aircraft  reciprocating engines in which a constant flow of fuel is fed  to injection nozzles in the heads of all cylinders just outside  of the intake valve. It differs from sequential fuel injection in  which a timed charge of high-pressure fuel is sprayed directly  into the combustion chamber of the cylinder.  Ground adjustable trim tab.  A metal trim tab on a control  surface that is not adjustable in flight. Bent in one direction  or another while on the ground to apply trim forces to the  control surface.  Gross weight.  The total weight of a fully loaded aircraft  including the fuel  oil  crew  passengers  and cargo.  Ground effect.  A condition of improved performance  encountered when an airplane is operating very close to the  ground. When an airplane’s wing is under the influence of  ground effect  there is a reduction in upwash  downwash  and  wingtip vortices. As a result of the reduced wingtip vortices   induced drag is reduced.  Fuel load.  The expendable part of the load of the airplane.  It includes only usable fuel  not fuel required to fill the lines  or that which remains trapped in the tank sumps.  Fuel tank sump.  A sampling port in the lowest part of the  fuel tank that the pilot can utilize to check for contaminants  in the fuel.  Fuselage.  The section of the airplane that consists of the  cabin and/or cockpit  containing seats for the occupants and  the controls for the airplane.  Ground idle.  Gas turbine engine speed usually 60-70 percent  of the maximum rpm range  used as a minimum thrust setting  for ground operations.  Ground loop.  A sharp  uncontrolled change of direction of  an airplane on the ground.  Gas generator.  The basic power producing portion of a  gas turbine engine and excluding such sections as the inlet  duct  the fan section  free power turbines  and tailpipe.  Each manufacturer designates what is included as the gas  generator  but generally consists of the compressor  diffuser   combustor  and turbine.  Ground power unit (GPU).  A type of small gas turbine  whose purpose is to provide electrical power  and/or air  pressure for starting aircraft engines. Aground unit is  connected to the aircraft when needed. Similar to an aircraft- installed auxiliary power unit.  Groundspeed (GS).  The actual speed of the airplane over the  ground. It is true airspeed adjusted for wind. Groundspeed  decreases with a headwind  and increases with a tailwind.  Gas turbine engine.  A form of heat engine in which burning  fuel adds energy to compressed air and accelerates the air  through the remainder of the engine. Some of the energy  is extracted to turn the air compressor  and the remainder  accelerates the air to produce thrust. Some of this energy can  be converted into torque to drive a propeller or a system of  rotors for a helicopter.  Ground track.  The aircraft’s path over the ground when  in flight.  G  G-8