Jeppesen Private Pilot Glossary
questions and answers
TRICYCLE GEAR ✔✔two main wheels located on either side of the fuselage and a third wheel,
the nosewheel, positioned on the nose of the airplane.
TROPOPAUSE ✔✔top of the troposphere, at an average altitude of 36,000 feet, which acts as a
lid to most water vapor and associated weather.
TROPOSPHERE ✔✔the layer of the atmosphere from the surface to an average altitude of
36,000 feet.
TRUE AIRSPEED (TAS) ✔✔the speed an aircraft is moving relative to the surrounding air.
TRUE ALTITUDE ✔✔the actual height of an object above mean sea level.
TRUE COURSE (TC) ✔✔the intended or desired direction of flight as measured on a chart
clockwise from true north.
TRUE HEADING (TH) ✔✔the direction the longitudinal axis of the airplane points with respect to
true north. equal to the true course plus or minus any wind correction angle.
UNCONTROLLED AIRPORT ✔✔nontowered airport, where control of VFR traffic is not exercised.
,UNCONTROLLED AIRSPACE ✔✔Class G airspace, where traffic control is not exercised.
UNICOM ✔✔a nongovernmental communications facility that provides airport information at
certain airports.
USABLE FUEL ✔✔the amount of fuel available during flight.
USEFUL LOAD ✔✔the difference between the basic empty weight of the airplane and the
maximum weight allowed by the manufacturer's specification.
VALLEY BREEZE ✔✔upslope wind flow caused by the heating of the mountain slope, which
warms the adjacent air.
VAPOR LOCK ✔✔bubbles of vapor in the fuel system that prevent fuel from reaching the
cylinders and making restart of a hot engine difficult. it can also occur after running a fuel tank
dry, allowing air to enter the fuel system.
VARIATION ✔✔angular difference between true north and magnetic north; indicated on charts
by isogonic lines.
VERY HIGH FREQUENCY ✔✔frequency band from 30 MHz to 300 MHz.
VFR CRUISING ALTITUDE ✔✔rule when flying VFR above 3,000 feet AGL on magnetic headings
from 0-179 degrees requires odd thousand-foot altitudes plus 500 feet and on headings from
180-359 degrees requires even thousand-foot altitudes plus 500 feet.
, VICTOR AIRWAY ✔✔an airway system based on the use of VOR facilities.
VISUAL FLIGHT RULES (VFR) ✔✔rules that specify minimum cloud clearance and visibility
requirements for flight. defines weather conditions and the type of flight plan under which an
aircraft is operating.
VISUAL PURPLE ✔✔another term for rhodopsin, the chemical created by the rods for
perception of dim light.
VOR ✔✔very high frequency omnidirectional range: ground-based navigational system that
provides course guidance.
WARM FRONT ✔✔the boundary between two airmasses where warm air is replacing cold air.
WARNING AREA ✔✔airspace of defined dimensions, extending from three nautical miles
outward from the coast of the united states, which can contain activity that is hazardous to
nonparticipating aircraft.
WEIGHT ✔✔downward force caused by gravity, opposes lift.
WIND CORRECTION ANGLE (WCA) ✔✔the angular difference between the heading of the
airplane and the course.
WIND SHEAR ✔✔a sudden, drastic shift in wind speed or direction in either the vertical or
horizontal plane.
questions and answers
TRICYCLE GEAR ✔✔two main wheels located on either side of the fuselage and a third wheel,
the nosewheel, positioned on the nose of the airplane.
TROPOPAUSE ✔✔top of the troposphere, at an average altitude of 36,000 feet, which acts as a
lid to most water vapor and associated weather.
TROPOSPHERE ✔✔the layer of the atmosphere from the surface to an average altitude of
36,000 feet.
TRUE AIRSPEED (TAS) ✔✔the speed an aircraft is moving relative to the surrounding air.
TRUE ALTITUDE ✔✔the actual height of an object above mean sea level.
TRUE COURSE (TC) ✔✔the intended or desired direction of flight as measured on a chart
clockwise from true north.
TRUE HEADING (TH) ✔✔the direction the longitudinal axis of the airplane points with respect to
true north. equal to the true course plus or minus any wind correction angle.
UNCONTROLLED AIRPORT ✔✔nontowered airport, where control of VFR traffic is not exercised.
,UNCONTROLLED AIRSPACE ✔✔Class G airspace, where traffic control is not exercised.
UNICOM ✔✔a nongovernmental communications facility that provides airport information at
certain airports.
USABLE FUEL ✔✔the amount of fuel available during flight.
USEFUL LOAD ✔✔the difference between the basic empty weight of the airplane and the
maximum weight allowed by the manufacturer's specification.
VALLEY BREEZE ✔✔upslope wind flow caused by the heating of the mountain slope, which
warms the adjacent air.
VAPOR LOCK ✔✔bubbles of vapor in the fuel system that prevent fuel from reaching the
cylinders and making restart of a hot engine difficult. it can also occur after running a fuel tank
dry, allowing air to enter the fuel system.
VARIATION ✔✔angular difference between true north and magnetic north; indicated on charts
by isogonic lines.
VERY HIGH FREQUENCY ✔✔frequency band from 30 MHz to 300 MHz.
VFR CRUISING ALTITUDE ✔✔rule when flying VFR above 3,000 feet AGL on magnetic headings
from 0-179 degrees requires odd thousand-foot altitudes plus 500 feet and on headings from
180-359 degrees requires even thousand-foot altitudes plus 500 feet.
, VICTOR AIRWAY ✔✔an airway system based on the use of VOR facilities.
VISUAL FLIGHT RULES (VFR) ✔✔rules that specify minimum cloud clearance and visibility
requirements for flight. defines weather conditions and the type of flight plan under which an
aircraft is operating.
VISUAL PURPLE ✔✔another term for rhodopsin, the chemical created by the rods for
perception of dim light.
VOR ✔✔very high frequency omnidirectional range: ground-based navigational system that
provides course guidance.
WARM FRONT ✔✔the boundary between two airmasses where warm air is replacing cold air.
WARNING AREA ✔✔airspace of defined dimensions, extending from three nautical miles
outward from the coast of the united states, which can contain activity that is hazardous to
nonparticipating aircraft.
WEIGHT ✔✔downward force caused by gravity, opposes lift.
WIND CORRECTION ANGLE (WCA) ✔✔the angular difference between the heading of the
airplane and the course.
WIND SHEAR ✔✔a sudden, drastic shift in wind speed or direction in either the vertical or
horizontal plane.
