the Aviation Dictionary

hazardous inflight weather advisory service (HIWAS) - heavy (aircraft)
authority, impulsivity, invulnerability, macho, and
resignation.
heat exchanger - Any device used to transfer heat from
one body to another.
hazardous inflight weather advisory service (HIWAS) heat lamp - An incandescent lamp that produces a
- Continuous recorded hazardous inflight weather maximum of infrared radiation with a minimum of
forecasts broadcasted to airborne pilots over selected visible light rays. Used for drying paint or for applying
VOR outlets defined as an HIWAS Broadcast Area.
heat to glued parts to decrease curing time.
hazardous weather information - Summary of heat load - The amount of heat that an air conditioner is
significant meteorological information (SIGMETI required to remove from an airplane cabin in order to
WS), convective significant meteorological maintain a constant cabin temperature.
information, (convective SIGMETWST), urgent pilot
heat of compression - The heat generated when a gas is
weather reports (urgent PIREPNUA), center weather
compressed.
advisories (CWA), airmen's meteorological
information (AIRMETWA) and any other weather heat pump - Moves heat from one location to another.
such as isolated thunderstorms that are rapidly A heat pump can generally be reversed so that it either
developing and increasing in intensity, or low ceilings adds heat (acts as a heater) or takes heat away (acts as
and visibilities that are becoming widespread which is an air conditioner).
considered significant and are not included in a current
hazardous weather advisory.
heat sink - 1. A device on which semiconductors can be
mounted to absorb the heat that would normally tend to
haze - Fine dust or salt particles dispersed through a
portion of the atmosphere; particles are so small they
cannot be felt or individually seen with the naked eye
damage them. 2. A heavy plate of conductive material
that will absorb or carry away heat. Especially useful in
welding.
(as compared with the large particle of dust), but
diminish the visibility; distinguished from fog by its
bluish or yellowish tinge.
heading - The direction in which the longitudinal axis
of the airplane points with respect to true or magnetic
north. Heading is equal to course plus or minus any
wind correction angle.
heads up display (HUD) -A system that displays flight
information on a transparent display in the line-of-sight
of the pilot so that information can be read without
looking down into the cockpit. Newest terminology is
Head-up Guidance System (HGS).
head-up guidance system (HGS)- See heads up
display.
headwind component - That portion of the wind which
acts straight down the runway toward the airplane on
takeoff orparallel to the line of flight when airborne.
headwork - Conscious, rational thought process when
making decisions.
heat - Energy associated with the motion of molecules
within a material. The more heat energy there is in a
material, the faster its molecules move.
heat capacity - The amount of heat energy required to
raise the temperature of a substance 1°C.
heat dissipation - The loss of heat or the transfer of
heat into another object or substance.
heat energy - Energy associated with the motion of the
molecules within a substance.
heat engine - Any mechanical device that converts heat
energy into mechanical energy. For example,
reciprocating and turbine engines are heat engines.
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heat treatment of a plastic resin - The operation in
which a cemented joint in a thermoplastic resin is held
at an elevated temperature so the entrapped solvent can
difise into a greater volume of the resin. This
decreases its concentration and increases the strength
of the joint.
heat treatment of metals -Any operation in which the
physical characteristics of a metal are changed by
heating. This includes annealing, hardening, tempering,
and normalizing.
heat value - The heat energy available per unit volume
of a fuel.
heater - Any device that produces controlled heating.
heating element - An electrical resistance wire that
glows red-hot to produce heat.
heat-shrinkable - A quality in a synthetic fiber that
allows a fabric to shrink when heat is applied.
heatshrinkable fabric - An inorganic fabric used to
cover light aircraft structures. The fabric is sewn and
put on the aircraft structure so that it is taut but not
tight. After securing the fabric to the structure with a
special adhesive, it is shrunk to the correct tautness by
ironing it with an ordinary household electric iron or by
heating it with a high wattage hair dryer. The material
is then given a coating of non-tautening dope.
Heaviside atmospheric layer - A layer of ionized
particles that surrounds the Earth. The ionosphere.
heavy (aircraft)- For the purposes of Wake Turbulence
Separation Minima, ATC classifies aircraft as Heavy,
Large, and Small. Heavy aircraft are capable of takeoff
weights of more than 255,000 pounds whether or not