Aeronautical Terms beginning with H
Handoff
An action taken to transfer the radar identification of an aircraft from one controller to another if the aircraft will enter the receiving controller’s airspace and radio communications with the aircraft will be transferred.
Have Numbers
Used by pilots to inform ATC that they have received runway, wind, and altimeter information only.
Hazardous Inflight Weather Advisory Service
Continuous recorded hazardous inflight weather forecasts broadcasted to airborne pilots over selected VOR outlets defined as an HIWAS Broadcast Area. Discontinued on January 8, 2020.
Hazardous Weather Information
Summary of significant meteorological information (SIGMET/WS), convective significant meteorological information (convective SIGMET/WST), urgent pilot weather reports (urgent PIREP/UUA), center weather advisories (CWA), airmen’s meteorological information (AIRMET/WA) and any other weather such as isolated thunderstorms that are rapidly developing and increasing in intensity, or low ceilings and visibilities that are becoming widespread which is considered significant and are not included in a current hazardous weather advisory.
HDTA
High Density Traffic Airports
Heading
The direction in which the nose of the aircraft is pointing during flight.
Heading Bug
A marker on the heading indicator that can be rotated to a specific heading for reference purposes, or to command an autopilot to fly that heading.
Heading Indicator
An instrument which senses airplane movement and displays heading based on a 360º azimuth, with the final zero omitted. The heading indicator, also called a directional gyro, is fundamentally a mechanical instrument designed to facilitate the use of the magnetic compass. The heading indicator is not affected by the forces that make the magnetic compass difficult to interpret.
Headwind Component
The component of atmospheric winds that acts opposite to the aircraft’s flightpath.
Heavy
An Aircraft Class Wake Turbulence Separation Minima. Aircraft capable of takeoff weights of 300,000 pounds or more whether or not they are operating at this weight during a particular phase of flight.
Helicopter
A rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors.
Helipad
A small, designated area, usually with a prepared surface, on a heliport, airport, landing/takeoff area, apron/ramp, or movement area used for takeoff, landing, or parking of helicopters.
Heliport
An area of land, water, or structure used or intended to be used for the landing and takeoff of helicopters and includes its buildings and facilities if any.
HEMS
Helicopter Emergency Medical Services
Hertz
The standard radio equivalent of frequency in cycles per second of an electromagnetic wave. Kilohertz (kHz) is a frequency of one thousand cycles per second. Megahertz (MHz) is a frequency of one million cycles per second.
HF
High Frequency.
HF Communications
High Frequency Communications.
Hg
Abbreviation for mercury, from the Latin hydrargyrum.
High Frequency
The frequency band between 3 and 30 MHz.
High Frequency Communications
High radio frequencies (HF) between 3 and 30 MHz used for air-to-ground voice communication in overseas operations.
High performance aircraft
An aircraft with an engine of more than 200 horsepower.
High Speed Exit
High Speed Taxiway.
High Speed Taxiway
A long radius taxiway designed 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 turn-off taxiway. The high speed taxiway is designed to expedite aircraft turning off the runway after landing, thus reducing runway occupancy time.
High Speed Turnoff
High Speed Taxiway.
HIRL
High-Intensity Runway Light System.
HIWAS
Hazardous Inflight Weather Advisory Service. Discontinued on January 8, 2020.
HIWAS Broadcast Area
A geographical area of responsibility including one or more HIWAS outlet areas assigned to an AFSS/FSS for hazardous weather advisory broadcasting. Discontinued on January 8, 2020.
HIWAS Outlet Area
An area defined as a 150 NM radius of a HIWAS outlet, expanded as necessary to provide coverage. Discontinued on January 8, 2020.
Hold-Short Point
A point on the runway beyond which a landing aircraft with a LAHSO clearance is not authorized to proceed. This point may be located prior to an intersecting runway, taxiway, predetermined point, or approach/departure flight path.
Hold-Short Position Lights
Flashing in-pavement white lights located at specified hold-short points.
Hold-Short Position Marking
The painted runway marking located at the hold-short point on all LAHSO runways.
Hold-Short Position Signs
Red and white holding position signs located alongside the hold-short point.
Horizon
The line of sight boundary between the earth and the sky.
Horizontal situation indicator (HSI)
A flight navigation instrument that combines the heading indicator with a CDI, in order to provide the pilot with better situational awareness of location with respect to the courseline.
How Do You Hear Me?
A question relating to the quality of the transmission or to determine how well the transmission is being received.
HSI
Horizontal Situation Indicator.
HUD
Head-Up Display.
Human factors
A multidisciplinary field encompassing the behavioral and social sciences, engineering, and physiology, to consider the variables that influence individual and crew performance for the purpose of optimizing human performance and reducing errors.
Hydroplaning
A condition that exists when landing on a surface with standing water deeper than the tread depth of the tires. When the brakes are applied, there is a possibility that the brake will lock up and the tire will ride on the surface of the water, much like a water ski. When the tires are hydroplaning, directional control and braking action are virtually impossible. An effective anti-skid system can minimize the effects of hydroplaning.
Hz
Hertz
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