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| Glossary |
Glossary of
Helicopter & Heliport Terms
Heliplanners has compiled the following definitions as a
reference source for our clients and other interested parties. We have drawn these definitions from a
variety of sources but in some cases have reworded them for added clarity. In other cases we have developed our own
definitions. These definitions have no
legal standing and are presented solely for general reference.
Italicized text within a definition
indicates a term that is defined elsewhere in the glossary.
Commonly
used acronyms and exhibits illustrating obstruction-clearance criteria in
generic form follow the definitions.
Above
Ground Level (AGL):
Elevation
of an elevated heliport above surrounding grade (as opposed to elevation above
mean sea level.)
Aerospatiale: See Eurocopter.
Agusta: See AgustaWestland
AgustaWestland: A helicopter manufacturer formed by the
merger of former companies Agusta (Italy) and Westland (Great
Britain)
Aircraft:
Any contrivance designed for
navigation of or flight in the air.
Airport
Land Use Commission (ALUC): An agency
organized within most California counties, as required by California’s Public
Utilities Code, which reviews a proposed heliport’s land use
compatibility issues under the guidelines contained in that county’s adopted
Airport Land Use Plan.
Airport
Master Record: An FAA form
(form 5010) that provides FAA with statistical information about an airport or heliport
for its national airports database.
Airspace
Determination:
A letter
issued by the FAA as the end product of the “airspace study” required by FAR
Part 157, Notice of Landing Area Proposal.
Except for unusual cases, an airspace determination expresses “no
objection” to use of airspace needed to operate to and from a heliport site. Therefore, it is not technically an
“approval.” The airspace determination
generally carries an 18-month expiration date from the date of issue but can be
extended for an additional 12 months upon written request.
Airspace
Study:
A study,
required under FAR Part 157, conducted by FAA staff, to determine a proposed
landing area’s (heliport’s) impact on safe and efficient use of the airspace
needed to operate to and from the site.
Air Traffic
Control (ATC):
A service
operated by appropriate authorities to promote the safe, orderly and
expeditious flow of air traffic.
Approach/Departure
Path:
The flight
path, normally centered within an approach surface, intended for helicopters to
follow when landing at or taking off from a heliport.
Approach
Surface: (See Exhibit 1.)
An imaginary surface, as defined
in FAR Part 77, that begins at the end of the primary surface (FATO) and
extends out and up along the approach/takeoff path. For heliports, it extends for a horizontal distance of 4,000 feet
with a slope of eight feet horizontal to one foot vertical (ten-to-one for U.S.
military heliports). The width of the
approach surface varies from the FATO’s width at its inner edge to 500 feet at
its outer edge. No object should
penetrate an approach surface’s elevation within its lateral boundaries.
Association
of Air Medical Services (AAMS):
The
industry trade organization composed primarily of companies dedicated to the
aerial transportation of injured or ill medical patients as well as human
organs.
Autogyro:
An aircraft that derives lift from
a rotor that rotates without engine power but solely by the aerodynamic forces
induced by the rotor’s motion along its flight path.
Automated
Flight Service Station:
An FAA
facility providing pilots with a number of aviation-related services including
weather briefing and filing of flight plans.
Autorotation:
The act of rotor rotation without
engine power but solely by the aerodynamic forces induced by the rotor’s motion
along its flight path.
Beacon:
See Heliport Beacon
Bell
Helicopter:
A
U.S.-based helicopter manufacturer – a division of Textron (Bell Helicopter
Textron).
Berm
Heliport:
See mound
heliport.
Blackhawk:
Any of several versions of the
Sikorsky UH-60 (or S-60) helicopter – a helicopter used by many U.S. and
foreign military agencies.
Boeing:
A manufacturer of military
helicopters (as well as many other commercial, military and space vehicles).
Boeing
Vertol:
See Boeing
Cal/OSHA:
California Occupational Safety and
Health Administration
Collective:
One of the primary controls on a
helicopter – controls lift.
Conditional Use Permit:
See Use Permit
Cyclic: One of the
primary controls on a helicopter – controls forward and lateral motion.
Design
Helicopter: A generic
helicopter that reflects the maximum weight, overall length, main rotor
diameter, fuel load, landing gear dimensions, etc. of all helicopters expected
to operate at the heliport.
Division of
Aeronautics (DOA): In
California, the state agency (a Division of the Department of Transportation --
Caltrans) that is charged by state law with reviewing and permitting heliports
and airports within the state. With
certain exceptions, all heliports must receive a Heliport Permit from DOA. Some other states also have permitting
requirements by similar agencies.
Elevated
Heliport:
A heliport
elevated above the surrounding terrain or above the surrounding roof.
Elevation:
The
elevation, expressed as the distance above mean sea level, of the highest point
of the FATO or FARA.
Emergency
Evacuation Facility:
A clear
area on the roof of a tall building that is designed to accommodate helicopters
engaged in firefighting and/or emergency evacuation operations related to
building safety but is not intended to function as a heliport for other reasons.
Enstrom:
A U.S.-based helicopter
manufacturer.
Eurocopter:
A helicopter manufacturer formed
by the merger or former companies MBB (Germany) and Aerospatiale (France).
FAA Form
5010:
See Airport
Master Record.
FAA Form
7460: See Notice of
Proposed Construction or Alteration.
FAA Form
7480: See Notice of
Landing Area Proposal.
Federal
Aviation Administration (FAA):
A division of the United States Department of Transportation that
regulates and promotes aviation in the United States. FAA publishes the Heliport Design advisory circular and
Federal Aviation Regulations.
Federal
Aviation Regulation Part 77, Objects Affecting Navigable Airspace:
The part of the FARs that
defines obstruction clearance criteria surrounding a heliport or airport
runway. Technically, FAR Part 77
criteria apply only to public use heliports and airports but they are
sometimes considered in the design of private use facilities as well.
Federal
Aviation Regulations Part 157, Notice of Landing Area Proposal:
The part of the FARs that
specifies that a project proponent submit an application for a new heliport to
FAA to initiate an “airspace study.”
The study, conducted by FAA staff, results in an airspace
determination.
Final
Approach and Takeoff Area (FATO):
(See Exhibit 1.) A defined area
over which the final phase of an approach to a hover, or a landing, is
completed and from which the takeoff is initiated. Also called the primary surface.
(Note: This area was also called the “takeoff and landing area” in older
FAA publications.)
Final
Approach Reference Area (FARA):
A 150-foot wide by at least 150-foot long obstacle-free area located at
the end of a precision instrument approach with its center aligned on the final
approach course.
Flight
Standards District Office (FSDO):
A local FAA office providing services to and oversight of the
aviation community. Normally, the
FSDO’s aviation safety inspector is the only FAA staffmember who will
make a site visit during the airspace determination process. The aviation safety inspector normally sends
his/her comments to FAA’s regional Flight Standards office.
Fuel/Water
Separator: A tank that
separates fuel and/or oil that could leak out of a helicopter from
stormwater. A fuel/water separator
directs rainwater into the local stormwater system while storing fuel and/or
oil for later removal.
Fuselage: The main structure, or central section, of
an aircraft, which normally contains the crew, passengers, cargo, etc.
General
Aviation Heliport: A public
use heliport intended to accommodate individuals, corporations and
helicopter air taxi operators.
Scheduled passenger services may be available.
Global
Positioning System (GPS):
A series of
geostationary satellites in Earth orbit that provide positioning information
for receivers on Earth. Aircraft
equipped with GPS receivers can use the satellites to locate their
position.
GPS
Approach:
An
instrument approach procedure to a heliport or runway in which pilots
rely upon information provided by GPS satellites for navigation.
Hangar: A building intended to be used for storage,
maintenance, etc. of aircraft (note correct spelling – not “hanger”).
Hazard to
aviation: Any object having a
substantial adverse effect upon the safe and efficient use of the navigable
airspace by aircraft or upon the operation of an air navigation facility. (Note: an obstruction is assumed to
be a hazard unless determined not to be a hazard by an FAA study.)
Height/Velocity
Diagram: A diagram
published, by a helicopter manufacturer, which depicts altitude/airspeed
combinations in which a pilot would not have enough time to transition from
powered flight to autorotation in event of an engine failure.
Helicopter: A type of rotorcraft normally
supported in the air by airfoils (rotors) mechanically rotated about an
approximately vertical axis.
Helicopter
Association International (HAI):
The industry trade organization dedicated to the advancement of the
civil helicopter industry.
Regular members of HAI are those members who own and operate
helicopters. Other classes of
membership are open to those individuals and organizations that support or have
supportive interests in the civil helicopter industry.
Helideck: A TLOF elevated above surrounding
roof or terrain.
Helipad:
A helicopter landing and/or parking
area on an airport. Also, a commonly
used generic term for any helicopter landing area.
Heliport: An area of land, water or structure used or
intended to be used for the landing and takeoff of helicopters with appurtenant
buildings and facilities.
Heliport
Beacon: A beacon light
intended to help pilots find the general vicinity of a heliport. Heliport beacons sometimes consist of only
one color but more often have three colors, typically green-white-yellow, to
differentiate them from two-color airport beacons. Beacons can have either a rotating or three-globe sequentially
flashing format.
Heliport
Reference Point: The
geographic position of a heliport expressed as its latitude and longitude
coordinates at:
·
The center of the FARA when the heliport has a
precision instrument approach procedure.
·
The center of the FATO, or the centroid of multiple
FATOs, for heliports having visual and/or nonprecision instrument approach
procedures.
Helispot: A term sometimes used in place of helistop.
Helistop: A minimal heliport for boarding and
discharging passengers and/or cargo.
For hospitals, this equates to patients and/or organs. A helistop does not normally include
refueling, maintenance or helicopter storage facilities although, at some
sites, one helicopter may be stored on the landing pad. The heliport/helistop relationship
has been described as similar to a bus terminal/bus stop relationship with
respect to the extent of services provided or expected.
Hospital
Heliport (Helistop):
A heliport
(helistop) limited to serving helicopters engaged in air ambulance or other
hospital-related functions.
Huey: Any of several versions of the Bell UH-1
helicopter – a helicopter used by many U.S. and foreign military agencies.
Imaginary
Surface: Specified geometric
plane in the airspace around a heliport or runway that is used to
identify areas that should be kept free of obstructions. The dimensions and slopes of the various
imaginary surfaces are defined in FAR Part 77 and, in this Glossary,
under “approach surface,” “primary surface” and “transitional
surface.”
Impact
Loading: The minimum load
that an elevated TLOF should be designed to accommodate to allow for
hard landings. Impact loading is
normally 1.5 times the weight of the heaviest helicopter expected to use the
facility.
Latitude: A geographic coordinate expressing a point’s
location as degrees, minutes and seconds north or south of the equator
(0º). Used with longitude to
define a specific location on the earth’s surface. Coordinates for a heliport normally define the center of
the TLOF or, in the case of multiple TLOF’s the centroid.
Longitude: A geographic coordinate expressing a point’s
location as degrees, minutes and seconds east or west of the Prime Meridian
(0º), which passes through Greenwich, England.
Used with latitude to define a specific location on the earth’s
surface. Coordinates for a heliport
normally define the center of the TLOF or, in the case of multiple
TLOF’s the centroid.
Magnetic
Bearing: True bearing
corrected for magnetic declination to account for geographical
difference between the true and magnetic north poles. Normally used to indicate flight path alignment.
Magnetic
Declination: The correction to a
true bearing to account for the geographic difference between the true and
magnetic poles. The declination value
varies, depending on location on the earth’s surface.
Major Use
Permit:
See Use
Permit.
Main Rotor: The large rotor on top of a helicopter that
provides the primary lift and propulsion for the aircraft.
Maximum
Gross Takeoff Weight (MGTOW):
The maximum weight with which an aircraft is permitted to takeoff. MGTOW includes the aircraft’s empty weight
plus the weight of fuel, oil, crew, passengers, baggage, cargo and removable
equipment.
MBB: See Eurocopter
MD
Helicopters: A U.S.-based
helicopter manufacturer.
Mean Sea
Level (MSL): Official elevations
of runways and heliports are reported in feet above mean sea level (the
midpoint between the highest and lowest sea levels)
Mound
Heliport: A heliport built
on an earthen mound or berm, normally with a ramp for access. The purpose of building a mound helistop is
normally to elevate the TLOF above cars, fences or other potential
obstructions. This allows cars to park
and circulate closer to the heliport without violating obstruction-clearance
criteria. This strategy is sometimes
used to minimize the loss of critically needed parking spaces.
NOTAR: A technology that eliminates the need for a tailrotor. NOTAR-equipped aircraft use airflow around
the tail boom to provide directional stability in lieu of a tailrotor. NOTAR technology was developed by McDonnell
Douglas (now part of Boeing) but is now owned by MD Helicopters, an
independent company.
Notice of
Landing Area Proposal: FAA
Form 7480, submitted along with other documentation, to initiate an airspace
study by FAA staff per FAR Part 157. The study results in an airspace determination.
Notice of
Proposed Construction or Alteration:
FAA Form 7460, submitted along with other documentation, to initiate
a study by FAA staff per FAR Part 77.
The study results in an
obstruction evaluation.
Obstruction:
Any object, including a parked
helicopter, exceeding the obstruction standards specified by FAR Part 77,
Subpart C, Obstruction Standards.
Obstruction
Evaluation:
A study
performed by FAA staff to determine if an object (building, tower, etc.)
proposed near an airport or heliport would constitute an obstruction
under the criteria specified in FAR Part 77 and, if so, if it would
constitute a hazard to aviation.
Obstruction
Light: A red light
designed to mark a potential airspace obstruction for pilots operating
in the airspace near a heliport or airport.
Operation: Either the landing or the takeoff of an
aircraft.
Perimeter
Light:
One of a
series of lights generally located at the outer perimeter of the TLOF or
FATO to outline the area for pilots at night. FAA’s Heliport Design advisory circular currently
recommends yellow lights however recent research indicates that green is easier
for pilots to distinguish in an urban lighting environment at night. Therefore, FAA’s forthcoming revised
advisory circular, expected to be published in 2003, will likely recommend
green perimeter lighting.
Perimeter
Stripe:
A white
stripe that outlines the TLOF to designate it for approaching pilots.
Pilot-Controlled
Lighting:
A system
allowing pilots to control heliport lighting via the aircraft radio
through a receiver/controller on the ground.
Any of a number of frequencies can be used for the receiver/controller,
the most common of which is 123.05 MHz.
Prevailing
Wind:
Represents
the general direction and speed of local winds under normal conditions. Ideally, a heliport should be laid out so
that approach and departure paths will be into the prevailing winds.
Primary
Surface: See Final
Approach and Takeoff Area (FATO).
Private Use
Heliport: A heliport
intended for the exclusive use of its owner and persons authorized by its
owner.
Public Use
Heliport: A heliport
available for use by the public without prior approval by the owner or
operator.
PVT: A legend required on private-use heliports
in California to inform pilots that the heliport is not open to the public.
Robinson:
A U.S.-based helicopter
manufacturer.
Rotor: A rotating
system of airfoils that either support in the air (main rotor) or
stabilize (tailrotor) a rotorcraft.
Rotorcraft: A power-driven aircraft, heavier than
air, which is supported in flight by one or more rotors.
Rotorwash: The local air circulation (wind) caused by a
helicopter’s spinning rotors.
Rotorway: A
U.S.-based manufacturer of kit-built experimental class helicopters.
Safety
Area: A defined area,
surrounding the FATO that is to be maintained free of objects above TLOF
elevation. It is intended to reduce the
risk of damage to helicopters accidentally diverging from the FATO, for
example while performing turning maneuvers over it. The minimum width for a safety area is, for hospital and other
PPR heliports, 1/3 the main rotor diameter or 10 feet, whichever is
larger; for public use general aviation heliports, 1/3 the main rotor diameter
or 20 feet, whichever is larger; and for public use transport heliports, 30
feet.
Safety Net: A device for fall protection surrounding an
elevated TLOF. A safety net is
intended to prevent falls as well as to warn people who might accidentally step
off the TLOF. FAA recommends a
five-foot wide safety net. However, for
projects in California, safety nets should be six feet wide, to satisfy
Cal-OSHA criteria.
Schweizer: A U.S.-based helicopter manufacturer.
Sikorsky:
A U.S.-based helicopter
manufacturer -- a division of United Technology. Also, Igor Sikorsky, Russian-born aircraft designer and
helicopter pioneer, commonly known as the “Father of the Helicopter.”
Skid: The (normally) tubular metal landing gear
members that support some types of helicopters on the ground. Skids are normally connected to the fuselage
by four cross members.
Skid Shoe: A metal strip that is strapped to a landing
skid to protect it from wear during landings.
Skid shoes are replaceable at much lower cost than skids.
Special Use
Permit: See Use Permit.
Tailrotor: The smaller rotor in the rear of a
conventionally designed helicopter that provides directional stability. Heliports should be designed to minimize
the potential for tailrotor strikes of people or objects. Therefore, access points to the heliport
should be well away from where a tailrotor would normally be expected during or
just after a normal approach of just before a normal departure.
Tiltrotor: A type of
powered-lift aircraft with characteristics of both rotary wing and fixed wing
aircraft. Tiltrotors have proprotors at
each wingtip. The proprotors can be
positioned to allow the aircraft to takeoff or land vertically, similar to a
helicopter or horizontally, similar to a fixed-wing aircraft. Once airborne, proprotors can be tilted
forward for horizontal flight. The U.S.
Marine Corps operates the VS-22 Osprey Tiltrotor. Bell and Agusta are partners in developing and
certifying the BA-609 civil tiltrotor.
Touchdown
and Liftoff Area (TLOF): A
load-bearing area, normally centered in the FATO, on which the
helicopter lands or takes off. The TLOF
is frequently called a helipad or helideck. (Note: Older FAA publications
referred to this area as the FATO, which now has a different
meaning. See above for current FATO
definition.)
Transitional
Surface: An imaginary
surface, as defined in FAR Part 77, that extends up and out from the
lateral boundaries of the primary surface and approach surfaces. For heliports, the transitional
surface’s slope is two feet horizontal to one foot vertical. It extends laterally to 250 feet either side
of the centerline of each designated
approach/takeoff path.
Transport
Canada: The agency that
publishes heliport development criteria in Canada. The agency is somewhat analogous to the U.S.
Federal Aviation
Administration.
Transport
Heliport: A public use
heliport intended to accommodate air carrier operators providing
scheduled or unscheduled service with large helicopters.
Tridair: A U.S.-based firm that developed the Gemini
st, a twin-engine conversion to the single engine Bell 206L LongRanger series
of helicopters.
True
Bearing: Bearing expressed
with respect to true north, often used to indicate flight path alignment.
Use Permit: A zoning approval required by many cities or
counties to develop and operate a heliport or helistop. The actual name can vary from one
jurisdiction to another. Some common
terminology includes conditional use permit, major use permit or special use
permit.
Vertiport: A facility designed to accommodate
powered-lift aircraft such as tiltrotors. A vertiport would normally have a short runway to facilitate
rolling takeoffs in a quieter and more fuel-efficient mode than true vertical
takeoffs.
Weight
Limitation Marking: For elevated
TLOFs, a marking indicating the maximum weight, in thousands of pounds,
that the TLOF is capable of supporting.
For example, a “12” indicates a 12,000-pound maximum aircraft weight.
Westland: See AgustaWestland.
Windcone: A device designed to visually indicate wind
speed and direction to pilots using a heliport. Heliports intended for nighttime use should
have a lighted windcone. The common way
of lighting windcones is with four downward directed flood lights mounted above
the windcone although some are internally lighted. Either method is acceptable.
A lighted windcone also normally includes a red obstruction light
mounted on its mast.
Windsock: (See Windcone.)
Selected Acronyms
AAMS: Association
of Air Medical Services
AC: Advisory
Circular (FAA publications)
ADO: Airports
District Office (FAA)
AFSS: Automated
Flight Service Station (FAA)
ALUC: Airport Land
Use Commission (California)
AGL: Elevation
Above Ground Level
AHS: American
Helicopter Society
ALUC: Airport
Land Use Commission (California)
AMS: Air
medical service
ARTCC: Air
Route Traffic Control Center
ATC: Air
Traffic Control
CAL/OSHA California
Occupational Safety and Health Administration
CUP: Conditional
Use Permit
DME: Distance
measuring equipment
DOA: Division
of Aeronautics (part of the California Department of Transportation – Caltrans)
DPS: Department
of Public Safety (Arizona)
EHLF: Emergency
helicopter landing facility
EMS: Emergency
medical service
ENG: Electronic
news gathering
FAA: Federal Aviation
Administration
FAR: Federal Aviation
Regulation
FARA: Final
approach reference area
FATO: Final
approach and takeoff area
FSDO: Flight
Standards District Office (FAA)
GPS: Global
Positioning System
HAI: Helicopter
Association International
HRP: Heliport
reference point
ICAO: International
Council of Aviation Officials
IFR: Instrument
flight rules
ILS: Instrument
landing system
IMC: Instrument
Meteorological Conditions
MGTOW: Maximum
gross takeoff weight
MHz Megahertz
MSL: Elevation
above Mean Sea Level
MUP: Major
use permit
NFPA National
Fire Protection Association
NOTAR: “No
tailrotor” technology
OE: Obstruction
evaluation
OSHPD: Office
of Statewide Healthcare Planning and Development (California)
PCL: Pilot-controlled
lighting
PVT: Private
Use
PUC: Public
Utilities Code
TLA: Three-letter
acronym
TLOF: Touchdown
and liftoff area
UHF: Ultra
high frequency
VASI Visual
approach slope indicator
VHF: Very
high frequency
VFR: Visual
flight rules
VMC: Visual
Meteorological Conditions
VOR: Very
high frequency omnirange
HELPFUL EXHIBITS:
Generic Airspace Obstruction-Clearance Explanatory Exhibits - PDF