the Aviation Dictionary

heterogeneous mixture . high-lift device
against a locally-produced signal from a variable- high frequency communications - High radio
frequency generator. When the beat is of zero frequencies (HF) between 3 and 30 MHz used for airfrequency,
the frequency of the incoming signal can be to-ground voice communication in overseas operations.
read from a dial or a digital display showing the
high
airplane - An airplane with an
frequency of the local generator.
engine - of more than 200 horsepower.
heterogeneous mixture - A mixture composed of
high pressure turbine - In gas turbine engines, the
dissimilar ingredients.
turbine rotor which drives the high pressure
hexadecimal number system - A number system that compressor in a dual or triple spool axial flow gas
uses the base 16. (The decimal system uses the base turbine engine.
ten).
high speed exit - See high speed taxiway.
hexagon -A figure that has six sides.
high speed taxiway - A long radius taxiway designed
hexagon head bolt - A bolt head shaped with six sides
(a hexagon).
hexode - An electron tube having six active elements.
and provided with lighting or marking to define the
path of aircraft, traveling at high speed (up to 60
knots), from the runway center to a point on the center
of a taxiway. Also referred to as long radius exit or
HF communications - See high frequency turn-off taxiway. The high speed taxiway is designed to
communications.
expedite aircrafi turning off the runway after landing,
thus reducing runway occupancy time.
hidden surfaces - Any surface represented on an
aircraft drawing that cannot be seen in a particular view
but is represented in outline form with hidden lines.
hierarchy of human needs - A listing by Abraham
Maslow of needs from the most basic to the most
fulfilling. These range from physical through safety,
social, and ego to self-fulfillment.
high - An area of high barometric pressure, with its
attendant system of winds; an anticyclone. Also
referred to as a high-pressure system.
high speed taxiway / turnoff (HST) - A long radius
taxiway designed and provided with lighting or
marking to define the path of an aircraft, traveling at
high speed (up to 60 knots), from the runway center to
a point on the center of a taxiway. Also referred to as
long radius exit or turnoff taxiway. The high speed
taxiway is designed to expedite aircraft turning off the
runway after landing, thus reducing runway occupancy
time.
high speed turnoff - See high speed taxiway.
high altitude checkout - FAR 61.31(f) requires specific
high strength steel Steel that has a tensile strength of
ground and flight training for a pilot to act as PIC of a
between 50,000 and 100,000 PSI.
pressurized airplane that has a service ceiling - or
maximum operating altitude, whichever is lower, high-bypass turbofan - Turbine engines with 4: 1
above 25,000 MSL. High-altitude checkouts require fan-to-engine bypass ratio or higher. That is, four or
both ground and flight training. Included in the ground more times as much air flows through the fan as
training is a thorough review of the physiological through the core engine.
aspects of high-altitude flight. An ove&iek of these
high-bypass turbofan engine - A turbofan engine in
effects is contained in Chapter 8 of the Aeronautical
which the mass airflow in pounds per second that
Information Manual (AIM) and AC 61-107, Operations
passes through the fan can be four times or more
of Aircraft at Altitudes Above 25,000 Feet MSL and/or
greater than that which is moved by the gas generator
MACH Numbers (Mmo) Greater Than .75. AC 61 -107
or core of the engine.
contains a recommended outline for a high-altitude
training program. An instructor needs a logbook high-carbon steel - Steel that contains more than 0.5%
endorsement for high-altitude operations to give flight carbon.
instruction in a pressurized airplane that has a service
high-frequency communications - Radio
ceiling or maximum operating altitude above 25,000
communication at a frequency that is above the upper
feet MSL.
end of the commercial AM broadcasting band.
high blower - The high-speed operation of a
single-stage, two -speed, internal supercharger system.
Usually about 10:l ratio.
high cycle fatigue - A condition seen as cracking or
stretching caused by vibration stresses above the design
limit of the engine.
high frequency - The frequency band between 3 and 30
MHz.
Aircraft Technical Book Company
P.O. Box 270
Tabernash, CO 80478
http:llwww.ACTechbooks.com
high-level language - The language of computer
instruction a computer can understand.
high-lift device - Any lift-modifying device such as a
slot, slat, or any of the forms of flaps that are used to
allow an airfoil to achieve a higher angle of attack
before airflow separation occurs.