4. Through the accumulation of night flying
experience in a particular area, the operator will
develop the ability to determine, prior to departure,
which areas can be considered supporting high or low
lighting conditions. Without that operational experi-
ence, low lighting considerations should be applied
by operators for both pre-flight planning and
operations until high lighting conditions are observed
or determined to be regularly available.
b. Astronomical Definitions and Background
Information for Night Operations
1. Definitions
(a) Horizon. Wherever one is located on or
near the Earth's surface, the Earth is perceived as
essentially flat and, therefore, as a plane. If there are
no visual obstructions, the apparent intersection of
the sky with the Earth's (plane) surface is the horizon,
which appears as a circle centered at the observer. For
rise/set computations, the observer's eye is consid-
ered to be on the surface of the Earth, so that the
horizon is geometrically exactly 90 degrees from the
local vertical direction.
(b) Rise, Set. During the course of a day the
Earth rotates once on its axis causing the phenomena
of rising and setting. All celestial bodies, the Sun,
Moon, stars and planets, seem to appear in the sky at
the horizon to the East of any particular place, then to
cross the sky and again disappear at the horizon to the
West. Because the Sun and Moon appear as circular
disks and not as points of light, a definition of rise or
set must be very specific, because not all of either
body is seen to rise or set at once.
(c) Sunrise and sunset refer to the times when
the upper edge of the disk of the Sun is on the horizon,
considered unobstructed relative to the location of
interest. Atmospheric conditions are assumed to be
average, and the location is in a level region on the
Earth's surface.
(d) Moonrise and moonset times are com-
puted for exactly the same circumstances as for
sunrise and sunset. However, moonrise and moonset
may occur at any time during a 24 hour period and,
consequently, it is often possible for the Moon to be
seen during daylight, and to have moonless nights. It
is also possible that a moonrise or moonset does not
occur relative to a specific place on a given date.
(e) Transit. The transit time of a celestial
body refers to the instant that its center crosses an
imaginary line in the sky - the observer's meridian -
running from north to south.
(f) Twilight. Before sunrise and again after
sunset there are intervals of time, known as
“twilight,” during which there is natural light
provided by the upper atmosphere, which does
receive direct sunlight and reflects part of it toward
the Earth's surface.
(g) Civil twilight is defined to begin in the
morning, and to end in the evening when the center of
the Sun is geometrically 6 degrees below the horizon.
This is the limit at which twilight illumination is
sufficient, under good weather conditions, for
terrestrial objects to be clearly distinguished.
2. Title 14 of the Code of Federal Regulations
applies these concepts and definitions in addressing
the definition of night (Section 1.1), the requirement
for aircraft lighting (Section 91.209) and pilot
recency of night experience (Section 61.67).
AIM 2/14/08
10-2-9
Special Operations
c. Information on Moon Phases and Changes in
the Percentage of the Moon Illuminated
From any location on the Earth, the Moon appears to
be a circular disk which, at any specific time, is
illuminated to some degree by direct sunlight. During
each lunar orbit (a lunar month), we see the Moon's
appearance change from not visibly illuminated
through partially illuminated to fully illuminated,
then back through partially illuminated to not
illuminated again. There are eight distinct, tradition-
ally recognized stages, called phases. The phases
designate both the degree to which the Moon is
illuminated and the geometric appearance of the
illuminated part. These phases of the Moon, in the
sequence of their occurrence (starting from New
Moon), are listed in FIG 10-2-3.
FIG 10-2-3
Phases of the Moon
New Moon - The Moon's unilluminated side is facing the Earth. The Moon is not visible
(except during a solar eclipse).
Waxing Crescent - The Moon appears to be partly but less than one-half illuminated by
direct sunlight. The fraction of the Moon's disk that is illuminated is increasing.
First Quarter - One-half of the Moon appears to be illuminated by direct sunlight. The
fraction of the Moon's disk that is illuminated is increasing.
Waxing Gibbous - The Moon appears to be more than one-half but not fully illuminated by
direct sunlight. The fraction of the Moon's disk that is illuminated is increasing.
Full Moon - The Moon's illuminated side is facing the Earth. The Moon appears to be
completely illuminated by direct sunlight.
Waning Gibbous - The Moon appears to be more than one-half but not fully
illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is
decreasing.
Last Quarter - One-half of the Moon appears to be illuminated by direct sunlight. The
fraction of the Moon's disk that is illuminated is decreasing.
Waning Crescent - The Moon appears to be partly but less than one-half illuminated by
direct sunlight. The fraction of the Moon's disk that is illuminated is decreasing.
AIM 2/14/08
10-2-10 Special Operations
1. The percent of the Moon's surface illumi-
nated is a more refined, quantitative description of the
Moon's appearance than is the phase. Considering the
Moon as a circular disk, at New Moon the percent
illuminated is 0; at First and Last Quarters it is 50%;
and at Full Moon it is 100%. During the crescent
phases the percent illuminated is between 0 and 50%
and during gibbous phases it is between 50% and
100%.
2. For practical purposes, phases of the Moon
and the percent of the Moon illuminated are
independent of the location on the Earth from where
the Moon is observed. That is, all the phases occur at
the same time regardless of the observer's position.
3. For more detailed information, refer to the
United States Naval Observatory site referenced
below.
d. Access to Astronomical Data for Determina-
tion of Moon Rise, Moon Set, and Percentage of
Lunar Disk Illuminated
1. Astronomical data for the determination of
Moon rise and set and Moon phase may be obtained
from the United States Naval Observatory using an
interactive query available at:
http://aa.usno.navy.mil/
2. Click on “Data Services,” and then on
“Complete Sun and Moon Data for One Day.”
3. You can obtain the times of sunrise, sunset,
moonrise, moonset, transits of the Sun and Moon, and
the beginning and end of civil twilight, along with
information on the Moon's phase by specifying the
date and location in one of the two forms on this web
page and clicking on the “Get data” button at the end
of the form. Form “A” is used for cities or towns in the
U.S. or its territories. Form “B” for all other locations.
An example of the data available from this site is
shown in TBL 10-2-2.
4. Additionally, a yearly table may be
constructed for a particular location by using the
“Table of Sunrise/Sunset, Moonrise/Moonset, or
Twilight Times for an Entire Year” selection.
TBL 10-2-2
Sample of Astronomical Data Available
from the Naval Observatory
The following information is provided for
New_Orleans, Orleans Parish, Louisiana
(longitude W90.1, latitude N30.0)
Tuesday
29 May 2007
Central Daylight Time
SUN
Begin civil twilight 5:34 a.m.
Sunrise 6:01 a.m.
Sun transit 12:58 p.m.
Sunset 7:55 p.m.
End civil twilight 8:22 p.m.
MOON
Moonrise 5:10 p.m. on preceding day
Moonset 4:07 a.m.
Moonrise 6:06 p.m.
Moon transit 11:26 p.m.
Moonset 4:41 a.m. on following day
Phase of the Moon on 29 May: waxing gibbous with
95% of the Moon's visible disk illuminated.
Full Moon on 31 May 2007 at 8:04 p.m. Central
Daylight Time.
10-2-3. Landing Zone Safety
a. This information is provided for use by
helicopter emergency medical services (HEMS)
pilots, program managers, medical personnel, law
enforcement, fire, and rescue personnel to further
their understanding of the safety issues concerning
Landing Zones (LZs). It is recommended that HEMS
operators establish working relationships with the
ground responder organizations they may come in
contact with in their flight operations and share this
information in order to establish a common frame of
reference for LZ selection, operations, and safety.
AIM 2/14/08
10-2-11
Special Operations
b. The information provided is largely based on
the booklet, LZ - Preparing the Landing Zone, issued
by National Emergency Medical Services Pilots
Association (NEMSPA), and the guidance developed
by the University of Tennessee Medical Center's
LIFESTAR program, and is used with their
permission. For additional information, go to
http://www.nemspa.org/.
c. Information concerning the estimation of wind
velocity is based on the Beaufort Scale. See
http://www.spc.noaa.gov/faq/tornado/beaufort.html
for more information.
d. Selecting a Scene LZ
1. If the situation requires the use of a helicopter,
first check to see if there is an area large enough to
land a helicopter safely.
FIG 10-2-4
Recommended Minimum Landing Zone Dimensions
2. For the purposes of FIG 10-2-4 the follow-
ing are provided as examples of relative helicopter
size:
(a) Small Helicopter: Bell 206/407, Euro-
copter AS-350/355, BO-105, BK-117.
(b) Medium Helicopter: Bell UH-1 (Huey)
and derivatives (Bell 212/412), Bell 222/230/430
Sikorsky S-76, Eurocopter SA-365.
(c) Large Helicopter: Boeing Chinook,
Eurocopter Puma, Sikorsky H-60 series
(Blackhawk), SK-92.
3. The LZ should be level, firm and free of loose
debris that could possibly blow up into the rotor
system.
4. The LZ should be clear of people, vehicles
and obstructions such as trees, poles and wires.
Remember that wires are difficult to see from the air.
The LZ must also be free of stumps, brush, post and
large rocks. See FIG 10-2-5.
FIG 10-2-5
Landing Zone Hazards
5. Keep spectators back at least 200 feet. Keep
emergency vehicles 100 feet away and have fire
equipment (if available) standing by. Ground
personnel should wear eye protection, if available,
during landing and takeoff operations. To avoid loose
objects being blown around in the LZ, hats should be
removed; if helmets are worn, chin straps must be
securely fastened.
6. Fire fighters (if available) should wet down
the LZ if it is extremely dusty.
AIM 2/14/08
10-2-12 Special Operations
e. Helping the Flightcrew Locate the Scene
1. If the LZ coordinator has access to a GPS unit,
the exact latitude and longitude of the LZ should be
relayed to the HEMS pilot. If unable to contact the
pilot directly, relay the information to the HEMS
ground communications specialist for relaying to the
pilot, so that they may locate your scene more
efficiently. Recognize that the aircraft may approach
from a direction different than the direct path from the
takeoff point to the scene, as the pilot may have to
detour around terrain, obstructions or weather
en_route.
2. Especially in daylight hours, mountainous
and densely populated areas can make sighting a
scene from the air difficult. Often, the LZ coordinator
on the ground will be asked if she or he can see or hear
the helicopter.
3. Flightcrews use a clock reference method for
directing one another's attention to a certain direction
from the aircraft. The nose of the aircraft is always
12_o'clock, the right side is 3 o'clock, etc. When the
LZ coordinator sees the aircraft, he/she should use
this method to assist the flightcrew by indicating the
scene's clock reference position from the nose of the
aircraft. For example, “Accident scene is located at
your 2 o'clock position.” See FIG 10-2-6.
FIG 10-2-6
“Clock” System for Identifying Positions
Relative to the Nose of the Aircraft
4. When the helicopter approaches the scene, it
will normally orbit at least one time as the flight crew
observes the wind direction and obstacles that could
interfere with the landing. This is often referred to as
the “high reconnaissance” maneuver.
f. Wind Direction and Touchdown Area
1. Determine from which direction the wind is
blowing. Helicopters normally land and takeoff into
the wind.
2. If contact can be established with the pilot,
either directly or indirectly through the HEMS
ground communications specialist, describe the wind
in terms of the direction the wind is from and the
speed.
3. Common natural sources of wind direction
information are smoke, dust, vegetation movement,
water streaks and waves. Flags, pennants, streamers
can also be used. When describing the direction, use
the compass direction from which the wind is
blowing (example: from the North-West).
4. Wind speed can be measured by small
hand-held measurement devices, or an observer's
estimate can be used to provide velocity information.
The wind value should be reported in knots (nautical
miles per hour). If unable to numerically measure
wind speed, use TBL 10-2-3 to estimate velocity.
Also, report if the wind conditions are gusty, or if the
wind direction or velocity is variable or has changed
recently.
5. If any obstacle(s) exist, insure their descrip-
tion, position and approximate height are
communicated to the pilot on the initial radio call.
AIM 2/14/08
10-2-13
Special Operations
TBL 10-2-3
Table of Common References for Estimating Wind Velocity
Wind
(Knots)
Wind
Classification
Appearance of Wind Effects
On the Water On Land
Less than 1 Calm Sea surface smooth and mirror-like Calm, smoke rises vertically
1-3 Light Air Scaly ripples, no foam crests Smoke drift indicates wind direction,
wind vanes are still
4-6 Light Breeze Small wavelets, crests glassy, no
breaking
Wind felt on face, leaves rustle, vanes
begin to move
7-10 Gentle Breeze Large wavelets, crests begin to break,
scattered whitecaps
Leaves and small twigs constantly
moving, light flags extended
11-16 Moderate Breeze Small waves 1-4 ft. becoming longer,
numerous whitecaps
Dust, leaves, and loose paper lifted,
small tree branches move
17-21 Fresh Breeze Moderate waves 4-8 ft. taking longer
form, many whitecaps, some spray
Small trees in leaf begin to sway
22-27 Strong Breeze Larger waves 8-13 ft., whitecaps
common, more spray
Larger tree branches moving, whistling
in wires
28-33 Near Gale Sea heaps up, waves 13-20 ft., white
foam streaks off breakers
Whole trees moving, resistance felt
walking against wind
34-40 Gale Moderately high (13-20 ft.) waves of
greater length, edges of crests begin to
break into spindrift, foam blown in
streaks
Whole trees in motion, resistance felt
walking against wind
41-47 Strong Gale High waves (20 ft.), sea begins to roll,
dense streaks of foam, spray may reduce
visibility
Slight structural damage occurs, slate
blows off roofs
48-55 Storm Very high waves (20-30 ft.) with
overhanging crests, sea white with
densely blown foam, heavy rolling,
lowered visibility
Seldom experienced on land, trees
broken or uprooted, “considerable
structural damage”
56-63 Violent Storm Exceptionally high (30-45 ft.) waves,
foam patches cover sea, visibility more
reduced
64+ Hurricane Air filled with foam, waves over 45_ft.,
sea completely white with driving spray,
visibility greatly reduced
EXAMPLE-
Wind from the South-East, estimated speed 15 knots. Wind shifted from North-East about fifteen minutes ago, and is gusty.
AIM 2/14/08
10-2-14 Special Operations
g. Night LZs
1. There are several ways to light a night LZ:
(a) Mark the touchdown area with five lights
or road flares, one in each corner and one indicating
the direction of the wind. See FIG 10-2-7.
FIG 10-2-7
Recommended Lighting for
Landing Zone Operations at Night
NOTE-
Road flares are an intense source of ignition and may be
unsuitable or dangerous in certain conditions. In any case,
they must be closely managed and firefighting equipment
should be present when used. Other light sources are
preferred, if available.
(b) If chemical light sticks may be used, care
should be taken to assure they are adequately secured
against being dislodged by the helicopter's rotor
wash.
(c) Another method of marking a LZ uses four
emergency vehicles with their low beam headlights
aimed toward the intended landing area.
(d) A third method for marking a LZ uses two
vehicles. Have the vehicles direct their headlight
beams into the wind, crossing at the center of the LZ.
(If fire/rescue personnel are available, the reflective
stripes on their bunker gear will assist the pilot
greatly.)
2. At night, spotlights, flood lights and hand
lights used to define the LZ are not to be pointed at the
helicopter. However, they are helpful when pointed
toward utility poles, trees or other hazards to the
landing aircraft. White lights such as spotlights,
flashbulbs and hi-beam headlights ruin the pilot's
night vision and temporarily blind him. Red lights,
however, are very helpful in finding accident
locations and do not affect the pilot's night vision as
significantly.
3. As in Day LZ operations, ensure radio contact
is accomplished between ground and air, if possible.
h. Ground Guide
1. When the helicopter is in sight, one person
should assist the LZ Coordinator by guiding the
helicopter into a safe landing area. In selecting an LZ
Coordinator, recognize that medical personnel
usually are very busy with the patient at this time. It
is recommended that the LZ Coordinator be someone
other than a medical responder, if possible. Eye
protection should be worn. The ground guide should
stand with his/her back to the wind and his/her arms
raised over his/her head (flashlights in each hand for
night operations.)
2. The pilot will confirm the LZ sighting by
radio. If possible, once the pilot has identified the LZ,
the ground guide should move out of the LZ.
3. As the helicopter turns into the wind and
begins a descent, the LZ coordinator should provide
assistance by means of radio contact, or utilize the
“unsafe signal” to wave off the helicopter if the LZ is
not safe (see FIG 10-2-8). The LZ Coordinator
should be far enough from the touchdown area that
he/she can still maintain visual contact with the pilot.
i. Assisting the Crew
1. After the helicopter has landed, do not
approach the helicopter. The crew will approach you.
2. Be prepared to assist the crew by providing
security for the helicopter. If asked to provide
security, allow no one but the crew to approach the
aircraft.
3. Once the patient is prepared and ready to load,
allow the crew to open the doors to the helicopter and
guide the loading of the patient.
4. When approaching or departing the helicop-
ter, always be aware of the tail rotor and always
follow the directions of the crew. Working around a
running helicopter can be potentially dangerous. The
environment is very noisy and, with exhaust gases
and rotor wash, often windy. In scene operations, the
surface may be uneven, soft, or slippery which can
lead to tripping. Be very careful of your footing in this
environment.
AIM 2/14/08
10-2-15
Special Operations
5. The tail rotor poses a special threat to
working around a running helicopter. The tail rotor
turns many times faster than the main rotor, and is
often invisible even at idle engine power. Avoid
walking towards the tail of a helicopter beyond the
end of the cabin, unless specifically directed by the
crew.
NOTE-
Helicopters typically have doors on the sides of the cabin,
but many use aft mounted “clamshell” type doors for
loading and unloading patients on litters or stretchers.
When using these doors, it is important to avoid moving any
further aft than necessary to operate the doors and
load/unload the patient. Again, always comply with the
crew’s instructions.
j. General Rules
1. When working around helicopters, always
approach and depart from the front, never from the
rear. Approaching from the rear can increase your risk
of being struck by the tail rotor, which, when at
operating engine speed, is nearly invisible.
2. To prevent injury or damage from the main
rotor, never raise anything over your head.
3. If the helicopter landed on a slope, approach
and depart from the down slope side only.
4. When the helicopter is loaded and ready for
take off, keep the departure path free of vehicles and
spectators. In an emergency, this area is needed to
execute a landing.
k. Hazardous Chemicals and Gases
1. Responding to accidents involving hazardous
materials requires special handling by fire/rescue
units on the ground. Equally important are the
preparations and considerations for helicopter
operations in these areas.
2. Hazardous materials of concern are those
which are toxic, poisonous, flammable, explosive,
irritating, or radioactive in nature. Helicopter
ambulance crews normally don’t carry protective
suits or breathing apparatuses to protect them from
hazardous materials.
3. The helicopter ambulance crew must be told
of hazardous materials on the scene in order to avoid
the contamination of the crew. Patients/victims
contaminated by hazardous materials may require
special precautions in packaging before loading on
the aircraft for the medical crew’s protection, or may
be transported by other means.
4. Hazardous chemicals and gases may be fatal
to the unprotected person if inhaled or absorbed
through the skin.
5. Upon initial radio contact, the helicopter crew
must be made aware of any hazardous gases in the
area. Never assume that the crew has already been
informed. If the aircraft were to fly through the
hazardous gases, the crew could be poisoned and/or
the engines could develop mechanical problems.
6. Poisonous or irritating gases may cling to a
victim’s clothing and go unnoticed until the patient is
loaded and the doors of the helicopter are closed. To
avoid possible compromise of the crew, all of these
patients must be decontaminated prior to loading.
l. Hand Signals
1. If unable to make radio contact with the
HEMS pilot, use the following signals:
FIG 10-2-8
Recommended Landing Zone Ground Signals
AIM 2/14/10-2-16 Special Operations
m. Emergency Situations
1. In the event of a helicopter accident in the
vicinity of the LZ, consider the following:
(a) Emergency Exits:
(1) Doors and emergency exits are typically prominently marked. If possible, operators should
familiarize ground responders with the door system
on their helicopter in preparation for an emergency
event.
(2) In the event of an accident during the LZ
operation, be cautious of hazards such as sharp and
jagged metal, plastic windows, glass, any rotating
components, such as the rotors, and fire sources, such
as the fuel tank(s) and the engine.
(b) Fire Suppression:
Helicopters used in HEMS operations are usually
powered by turboshaft engines, which use jet fuel.
Civil HEMS aircraft typically carry between 50 and
250 gallons of fuel, depending upon the size of the
helicopter, and planned flight duration, and the fuel
remaining after flying to the scene. Use water to
control heat and use foam over fuel to keep vapors
from ignition sources.
10-2-4. Emergency Medical Service (EMS)
Multiple Helicopter Operations
a. Background. EMS helicopter operators often
overlap other EMS operator areas. Standardized
procedures can enhance the safety of operating
multiple helicopters to landing zones (LZs) and to
hospital heliports. Communication is the key to
successful operations and in maintaining organization between helicopters, ground units and
communication centers. EMS helicopter operators
which operate in the same areas should establish joint
operating procedures and provide them to related
agencies.
b. Recommended Procedures.
1. Landing Zone Operations. The first helicopter to arrive on-scene should establish
communications with the ground unit at least 10 NMs
from the LZ to receive a LZ briefing and to provide
ground control the number of helicopters that can be
expected. An attempt should be made to contact other
helicopters on 123.025 to pass on to them pertinent
LZ information and the ground unit’s frequency.
Subsequent helicopters arriving on scene should
establish communications on 123.025 at least 10
NMs from the LZ. After establishing contact on
123.025, they should contact the ground unit for
additional information. All helicopters should
monitor 123.025 at all times.
(a) If the landing zone is not established by
the ground unit when the first helicopter arrives,
then the first helicopter should establish altitude
and orbit location requirements for the other
arriving helicopters. Recommended altitude separation between helicopters is 500 feet (weather and
airspace permitting). Helicopters can orbit on
cardinal headings from the scene coordinates. (See
FIG 10-2-9.)
(b) Upon landing in the LZ, the first
helicopter should update the other helicopters on the
LZ conditions, i.e., space, hazards and terrain.
(c) Before initiating any helicopter movement to leave the LZ, all operators should attempt to
contact other helicopters on 123.025, and state their
position and route of flight intentions for departing
the LZ.
2. Hospital Operations. Because many
hospitals require landing permission and have
established procedures (frequencies to monitor,
primary and secondary routes for approaches and
departures, and orbiting areas if the heliport is
occupied) pilots should always receive a briefing
from the appropriate facility (communication center,
flight following, etc.) before proceeding to the
hospital.
(a) In the event of multiple helicopters
coming into the hospital heliport, the helicopter
nearest to the heliport should contact other inbound
helicopters on 123.025 and establish intentions.
Follow the guidelines established in the LZ
operations.
(b) To facilitate approach times, the pilot-in-
command of the helicopter occupying the hospital
heliport should advise any other operators whether
the patient will be off loaded with the rotor blades
turning or stopped, and the approximate time to do so.
(c) Before making any helicopter movement
to leave the hospital heliport, all operators should
attempt to contact other helicopters on 123.025 and
state their position and route of flight intentions for
departing the heliport.
3/15/07 7110.65R CHG 2 AIM 7/31/08
AIM 2/14/08
10-2-17
Special Operations
FIG 10-2-9
EMS Multiple Helicopter LZ/Heliport Operation
NOTE-
If the LZ/hospital heliport weather conditions or airspace altitude restrictions prohibit the recommended vertical
separation, 1 NM separations should be kept between helicopter orbit areas.
7/31/08 AIM
AIM 2/14/08
Appendix 1-1
Bird/Other Wildlife Strike Report
Appendix 1. Bird/Other Wildlife Strike Report
AIM 2/14/08
Appendix 1-2 Bird/Other Wildlife Strike Report
FOLD AND TAPE HERE
AIM 2/14/08
Appendix 2-1
Volcanic Activity Reporting Form (VAR)
Appendix 2. Volcanic Activity Reporting Form (VAR)
E-mail address: GVN@volcano.si.edu
AIM 2/14/08
Appendix 3-1
Laser Beam Exposure Questionnaire
Appendix 3. Laser Beam Exposure Questionnaire
AIM 2/14/08
Appendix 4-1
Abbreviations/Acronyms
Appendix 4. Abbreviations/Acronyms
As used in this manual, the following abbreviations/
acronyms have the meanings indicated.
Abbreviation/
Acronym
Meaning
AAWU . . . . . Alaskan Aviation Weather Unit
AC . . . . . . . . Advisory Circular
ACAR . . . . . Aircraft Communications Addressing and
Reporting System
ADCUS . . . . Advise Customs
ADDS . . . . . . Aviation Digital Data Service
ADF . . . . . . . Automatic Direction Finder
ADIZ . . . . . . Air Defense Identification Zone
ADS-B . . . . . Automatic Dependent
Surveillance-Broadcast
AFB . . . . . . . Air Force Base
AFCS . . . . . . Automatic Flight Control System
A/FD . . . . . . Airport/Facility Directory
AFIS . . . . . . . Automatic Flight Information Service
AFM . . . . . . . Aircraft Flight Manual
AFSS . . . . . . Automated Flight Service Station
AGL . . . . . . . Above Ground Level
AHRS . . . . . . Attitude Heading Reference System
AIM . . . . . . . Aeronautical Information Manual
AIRMET . . . Airmen’s Meteorological Information
ALD . . . . . . . Available Landing Distance
ALS . . . . . . . Approach Light Systems
AMSL . . . . . Above Mean Sea Level
ANP . . . . . . . Actual Navigation Performance
AOCC . . . . . Airline Operations Control Center
AP . . . . . . . . Autopilot System
APV . . . . . . . Approach with Vertical Guidance
ARENA . . . . Areas Noted for Attention
ARFF IC . . . . Aircraft Rescue and Fire Fighting Incident
Commander
ARINC . . . . . Aeronautical Radio Incorporated
ARO . . . . . . . Airport Reservations Office
ARSA . . . . . . Airport Radar Service Area
ARSR . . . . . . Air Route Surveillance Radar
ARTCC . . . . . Air Route Traffic Control Center
ARTS . . . . . . Automated Radar Terminal System
ASDE-X . . . Airport Surface Detection Equipment -
Model X
ASOS . . . . . . Automated Surface Observing System
ASR . . . . . . . Airport Surveillance Radar
ASRS . . . . . . Aviation Safety Reporting System
ATC . . . . . . . Air Traffic Control
Abbreviation/
Acronym
Meaning
ATCRBS . . . . Air Traffic Control Radar Beacon System
ATCSCC . . . . Air Traffic Control System Command
Center
ATCT . . . . . . Airport Traffic Control Tower
ATD . . . . . . . Along-Track Distance
ATIS . . . . . . . Automatic Terminal Information Service
ATT . . . . . . . Attitude Retention System
AWC . . . . . . . Aviation Weather Center
AWOS . . . . . Automated Weather Observing System
AWSS . . . . . . Automated Weather Sensor System
AWTT . . . . . Aviation Weather Technology Transfer
AWW . . . . . . Severe Weather Forecast Alert
BBS . . . . . . . Bulletin Board System
BC . . . . . . . . Back Course
C/A . . . . . . . . Coarse Acquisition
CARTS . . . . . Common Automated Radar Terminal
System (ARTS) (to include ARTS IIIE and
ARTS IIE)
CAT . . . . . . . Clear Air Turbulence
CD . . . . . . . . Controller Display
CDI . . . . . . . . Course Deviation Indicator
CDR . . . . . . . Coded Departure Route
CERAP . . . . . Combined Center/RAPCON
CFA . . . . . . . Controlled Firing Area
CFIT . . . . . . . Controlled Flight into Terrain
CFR . . . . . . . Code of Federal Regulations
COA . . . . . . . Certificate of Waiver or Authorization
CPDLC . . . . . Controller Pilot Data Link
Communications
CTAF . . . . . . Common Traffic Advisory Frequency
CVFP . . . . . . Charted Visual Flight Procedure
CVRS . . . . . . Computerized Voice Reservation System
CWA . . . . . . . Center Weather Advisory
CWSU . . . . . Center Weather Service Unit
DA . . . . . . . . Decision Altitude
DCA . . . . . . . Ronald Reagan Washington National
Airport
DCP . . . . . . . Data Collection Package
DER . . . . . . . Departure End of Runway
DF . . . . . . . . Direction Finder
DH . . . . . . . . Decision Height
DME . . . . . . . Distance Measuring Equipment
DME/N . . . . . Standard DME
DME/P . . . . . Precision DME
DOD . . . . . . . Department of Defense
7/31/08 AIM
AIM 2/14/Appendix 4-2 Abbreviations/Acronyms
Abbreviation/
Acronym
Meaning
DP . . . . . . . . Instrument Departure Procedure
DPU . . . . . . . Data Processor Unit
DRT . . . . . . . Diversion Recovery Tool
DRVSM . . . . Domestic Reduced Vertical Separation
Minimum
DUATS . . . . . Direct User Access Terminal System
DVA . . . . . . . Diverse Vector Area
DVFR . . . . . . Defense Visual Flight Rules
DVRSN . . . . Diversion
EDCT . . . . . . Expect Departure Clearance Time
EFAS . . . . . . En Route Flight Advisory Service
ELT . . . . . . . . Emergency Locator Transmitter
EMAS . . . . . Engineered Materials Arresting System
EPE . . . . . . . Estimate of Position Error
ESV . . . . . . . Expanded Service Volume
ETA . . . . . . . Estimated Time of Arrival
ETD . . . . . . . Estimated Time of Departure
ETE . . . . . . . Estimated Time En Route
EWINS . . . . . Enhanced Weather Information System
EWR . . . . . . . Newark International Airport
FA . . . . . . . . . Area Forecast
FAA . . . . . . . Federal Aviation Administration
FAF . . . . . . . . Final Approach Fix
FAWP . . . . . . Final Approach Waypoint
FB . . . . . . . . . Fly-by
FCC . . . . . . . Federal Communications Commission
FD . . . . . . . . Flight Director System
FDC . . . . . . . Flight Data Center
FDE . . . . . . . Fault Detection and Exclusion
FIR . . . . . . . . Flight Information Region
FIS . . . . . . . . Flight Information Service
FISDL . . . . . Flight Information Services Data Link
FLIP . . . . . . . Flight Information Publication
FMS . . . . . . . Flight Management System
FMSP . . . . . . Flight Management System Procedure
FO . . . . . . . . Fly-over
FPNM . . . . . . Feet Per Nautical Mile
FSDO . . . . . . Flight Standards District Office
FSS . . . . . . . . Flight Service Station
GBAS . . . . . . Ground Based Augmentation System
GEO . . . . . . . Geostationary Satellite
GLS . . . . . . . GNSS Landing System
GNSS . . . . . . Global Navigation Satellite System
GNSSP . . . . . Global Navigation Satellite System Panel
GPS . . . . . . . Global Positioning System
GRI . . . . . . . . Group Repetition Interval
GSD . . . . . . . Geographical Situation Display
Abbreviation/
Acronym
Meaning
GUS . . . . . . . Ground Uplink Station
HAT . . . . . . . Height Above Touchdown
HDTA . . . . . . High Density Traffic Airports
HEMS . . . . . Helicopter Emergency Medical Services
HIRL . . . . . . High Intensity Runway Lights
HIWAS . . . . . Hazardous Inflight Weather Advisory
Service
HRR . . . . . . . Helicopter Rapid Refueling Procedures
Hz . . . . . . . . . Hertz
IAF . . . . . . . . Initial Approach Fix
IAP . . . . . . . . Instrument Approach Procedure
IAS . . . . . . . . Indicated Air Speed
IAWP . . . . . . Initial Approach Waypoint
ICAO . . . . . . International Civil Aviation Organization
IF . . . . . . . . . Intermediate Fix
IFIM . . . . . . . International Flight Information Manual
IFR . . . . . . . . Instrument Flight Rules
ILS . . . . . . . . Instrument Landing System
ILS/PRM . . . Instrument Landing System/Precision
Runway Monitor
IM . . . . . . . . . Inner Marker
IMC . . . . . . . Instrument Meteorological Conditions
INS . . . . . . . . Inertial Navigation System
IOC . . . . . . . . Initial Operational Capability
IR . . . . . . . . . IFR Military Training Route
IRU . . . . . . . . Inertial Reference Unit
ITWS . . . . . . Integrated Terminal Weather System
JFK . . . . . . . . John F. Kennedy International Airport
kHz . . . . . . . . Kilohertz
LAA . . . . . . . Local Airport Advisory
LAAS . . . . . . Local Area Augmentation System
LAHSO . . . . Land and Hold Short Operations
LAWRS . . . . Limited Aviation Weather Reporting
Station
LDA . . . . . . . Localizer Type Directional Aid
LDA/PRM . . Localizer Type Directional Aid/Precision
Runway Monitor
LGA . . . . . . . LaGuardia Airport
LIRL . . . . . . . Low Intensity Runway Lights
LLWAS . . . . . Low Level Wind Shear Alert System
LLWAS NE . Low Level Wind Shear Alert System
Network Expansion
LLWAS-RS . Low Level Wind Shear Alert System
Relocation/Sustainment
LNAV . . . . . . Lateral Navigation
LOC . . . . . . . Localizer
LOP . . . . . . . Line-of-position
LORAN . . . . Long Range Navigation System
3/15/07 7110.65R CHG 2 AIM 7/31/08
AIM 2/14/08
Appendix 4-3
Abbreviations/Acronyms
Abbreviation/
Acronym
Meaning
LP . . . . . . . . . Localizer Performance
LPV . . . . . . . Localizer Performance with Vertical
Guidance
LZ . . . . . . . . . Landing Zone
MAHWP . . . Missed Approach Holding Waypoint
MAP . . . . . . . Missed Approach Point
MAWP . . . . . Missed Approach Waypoint
MDA . . . . . . Minimum Descent Altitude
MEA . . . . . . . Minimum En Route Altitude
MEARTS . . . Micro En Route Automated Radar
Tracking System
METAR . . . . Aviation Routine Weather Report
MHz . . . . . . . Megahertz
MIRL . . . . . . Medium Intensity Runway Lights
MLS . . . . . . . Microwave Landing System
MM . . . . . . . Middle Marker
MOA . . . . . . Military Operations Area
MOCA . . . . . Minimum Obstruction Clearance Altitude
MRA . . . . . . Minimum Reception Altitude
MRB . . . . . . . Magnetic Reference Bearing
MSA . . . . . . . Minimum Safe Altitude
MSAW . . . . . Minimum Safe Altitude Warning
MSL . . . . . . . Mean Sea Level
MTI . . . . . . . Moving Target Indicator
MTOS . . . . . . Mountain Obscuration
MTR . . . . . . . Military Training Route
MVA . . . . . . . Minimum Vectoring Altitude
MWA . . . . . . Mountain Wave Activity
MWO . . . . . . Meteorological Watch Office
NACO . . . . . National Aeronautical Charting Office
NAS . . . . . . . National Airspace System
NASA . . . . . . National Aeronautics and Space
Administration
NAVAID . . . . Navigational Aid
NAVCEN . . . Coast Guard Navigation Center
NCWF . . . . . National Convective Weather Forecast
NDB . . . . . . . Nondirectional Radio Beacon
NEXRAD . . . Next Generation Weather Radar
NFDC . . . . . . National Flight Data Center
NGA . . . . . . . National Geospatial-Intelligence Agency
NIDS . . . . . . National Institute for Discovery Sciences
NM . . . . . . . . Nautical Mile
NMAC . . . . . Near Midair Collision
NOAA . . . . . National Oceanic and Atmospheric
Administration
NOPAC . . . . North Pacific
NoPT . . . . . . No Procedure Turn Required
NOTAM . . . . Notice to Airmen
Abbreviation/
Acronym
Meaning
NPA . . . . . . . Nonprecision Approach
NRS . . . . . . . Navigation Reference System
NSA . . . . . . . National Security Area
NSW . . . . . . . No Significant Weather
NTAP . . . . . . Notices to Airmen Publication
NTSB . . . . . . National Transportation Safety Board
NTZ . . . . . . . No Transgression Zone
NWS . . . . . . . National Weather Service
OAT . . . . . . . Outside Air Temperature
OBS . . . . . . . Omni-bearing Selector
ODP . . . . . . . Obstacle Departure Procedure
OIS . . . . . . . . Operational Information System
OIS . . . . . . . . Obstacle Identification Surface
OM . . . . . . . . Outer Marker
ORD . . . . . . . Chicago O’Hare International Airport
PA . . . . . . . . . Precision Approach
PAPI . . . . . . . Precision Approach Path Indicator
PAR . . . . . . . Precision Approach Radar
PAR . . . . . . . Preferred Arrival Route
PC . . . . . . . . . Personal Computer
P/CG . . . . . . . Pilot/Controller Glossary
PDC . . . . . . . Pre-departure Clearance
PFD . . . . . . . Personal Flotation Device
PinS . . . . . . . Point-in-Space
PIREP . . . . . . Pilot Weather Report
POB . . . . . . . Persons on Board
POFZ . . . . . . Precision Obstacle Free Zone
POI . . . . . . . . Principal Operations Inspector
PPS . . . . . . . . Precise Positioning Service
PRM . . . . . . . Precision Runway Monitor
PT . . . . . . . . . Procedure Turn
QICP . . . . . . Qualified Internet Communications
Provider
RA . . . . . . . . Resolution Advisory
RAA . . . . . . . Remote Advisory Airport
RAIM . . . . . . Receiver Autonomous Integrity Monitoring
RAIS . . . . . . Remote Airport Information Service
RBDT . . . . . . Ribbon Display Terminals
RCAG . . . . . Remote Center Air/Ground
RCC . . . . . . . Rescue Coordination Center
RCLS . . . . . . Runway Centerline Lighting System
RCO . . . . . . . Remote Communications Outlet
RD . . . . . . . . Rotor Diameter
REIL . . . . . . . Runway End Identifier Lights
RFM . . . . . . . Rotorcraft Flight Manual
RLIM . . . . . . Runway Light Intensity Monitor
RMI . . . . . . . Radio Magnetic Indicator
7/08 31/AIM
AIM 2/14/Appendix 4-4 Abbreviations/Acronyms
Abbreviation/
Acronym
Meaning
RNAV . . . . . . Area Navigation
RNP . . . . . . . Required Navigation Performance
ROC . . . . . . . Required Obstacle Clearance
RPAT . . . . . . RNP Parallel Approach Runway
Transitions
RVR . . . . . . . Runway Visual Range
RVSM . . . . . . Reduced Vertical Separation Minimum
SAAAR . . . . Special Aircraft and Aircrew Authorization
Required
SAM . . . . . . . System Area Monitor
SAR . . . . . . . Search and Rescue
SAS . . . . . . . Stability Augmentation System
SBAS . . . . . . Satellite-based Augmentation System
SCAT-1
DGPS . . . . . . Special Category I Differential GPS
SDF . . . . . . . Simplified Directional Facility
SFL . . . . . . . . Sequenced Flashing Lights
SFR . . . . . . . Special Flight Rules
SIAP . . . . . . . Standard Instrument Approach Procedure
SID . . . . . . . . Standard Instrument Departure
SIGMET . . . . Significant Meteorological Information
SM . . . . . . . . Statute Mile
SMGCS . . . . Surface Movement Guidance Control
System
SNR . . . . . . . Signal-to-noise Ratio
SOIA . . . . . . Simultaneous Offset Instrument
Approaches
SOP . . . . . . . Standard Operating Procedure
SPC . . . . . . . Storm Prediction Center
SPS . . . . . . . . Standard Positioning Service
STAR . . . . . . Standard Terminal Arrival
STARS . . . . . Standard Terminal Automation
Replacement System
STMP . . . . . . Special Traffic Management Program
SWSL . . . . . . Supplemental Weather Service Locations
TA . . . . . . . . . Traffic Advisory
TAA . . . . . . . Terminal Arrival Area
TAC . . . . . . . Terminal Area Chart
TACAN . . . . Tactical Air Navigation
TAF . . . . . . . Aerodrome Forecast
TAS . . . . . . . True Air Speed
TCAS . . . . . . Traffic Alert and Collision Avoidance
System
TCH . . . . . . . Threshold Crossing Height
TD . . . . . . . . Time Difference
TDLS . . . . . . Tower Data Link System
TDWR . . . . . Terminal Doppler Weather Radar
TDZL . . . . . . Touchdown Zone Lights
TEC . . . . . . . Tower En Route Control
Abbreviation/
Acronym
Meaning
TIBS . . . . . . . Telephone Information Briefing Service
TIPH . . . . . . . Taxi into Position and Hold
TIS . . . . . . . . Traffic Information Service
TIS-B . . . . . . Traffic Information Service-Broadcast
TLS . . . . . . . Transponder Landing System
TPP . . . . . . . . Terminal Procedures Publications
TRSA . . . . . . Terminal Radar Service Area
TSO . . . . . . . Technical Standard Order
TWEB . . . . . Transcribed Weather Broadcast
TWIB . . . . . . Terminal Weather Information for Pilots
System
UA . . . . . . . . Unmanned Aircraft
UAS . . . . . . . Unmanned Aircraft System
UAV . . . . . . . Unmanned Aerial Vehicle
UFO . . . . . . . Unidentified Flying Object
UHF . . . . . . . Ultrahigh Frequency
U.S. . . . . . . . United States
USCG . . . . . . United States Coast Guard
UTC . . . . . . . Coordinated Universal Time
UWS . . . . . . . Urgent Weather SIGMET
VAR . . . . . . . Volcanic Activity Reporting
VASI . . . . . . . Visual Approach Slope Indicator
VCOA . . . . . Visual Climb Over the Airport
VDA . . . . . . . Vertical Descent Angle
VDP . . . . . . . Visual Descent Point
VFR . . . . . . . Visual Flight Rules
VGSI . . . . . . Visual Glide Slope Indicator
VHF . . . . . . . Very High Frequency
VIP . . . . . . . . Video Integrator Processor
VMC . . . . . . Visual Meteorological Conditions
VMINI . . . . . . Instrument flight minimum speed, utilized
in complying with minimum limit speed
requirements for instrument flight
VNAV . . . . . . Vertical Navigation
VNE . . . . . . . Never exceed speed
VNEI . . . . . . . Instrument flight never exceed speed,
utilized instead of VNE for compliance with
maximum limit speed requirements for
instrument flight
VOR . . . . . . . Very High Frequency Omni-directional
Range
VORTAC . . . VHF Omni-directional Range/Tactical Air
Navigation
VOT . . . . . . . VOR Test Facility
VR . . . . . . . . VFR Military Training Route
VREF. . . . . . . . . The reference landing approach speed,
usually about 1.3 times Vso plus 50 percent
of the wind gust speed in excess of the
mean wind speed.
3/15/07 7110.65R CHG 2 AIM 7/31/08
AIM 2/14/08
Appendix 4-5
Abbreviations/Acronyms
Abbreviation/
Acronym
Meaning
VSO. . . . . . . . . . The stalling speed or the minimum steady
flight speed in the landing configuration at
maximum weight.
VTF . . . . . . . Vector to Final
VV . . . . . . . . Vertical Visibility
VVI . . . . . . . Vertical Velocity Indicator
VY . . . . . . . . Speed for best rate of climb
VYI . . . . . . . . Instrument climb speed, utilized instead of
VY for compliance with the climb
requirements for instrument flight
WA . . . . . . . . AIRMET
WAAS . . . . . Wide Area Augmentation System
WAC . . . . . . . World Aeronautical Chart
WFO . . . . . . . Weather Forecast Office
WGS-84 . . . . World Geodetic System of 1984
Abbreviation/
Acronym
Meaning
WMO . . . . . . World Meteorological Organization
WMS . . . . . . Wide-Area Master Station
WMSC . . . . . Weather Message Switching Center
WMSCR . . . . Weather Message Switching Center
Replacement
WP . . . . . . . . Waypoint
WRS . . . . . . . Wide-Area Ground Reference Station
WS . . . . . . . . SIGMET
WSO . . . . . . Weather Service Office
WSP . . . . . . . Weather System Processor
WST . . . . . . . Convective Significant Meteorological
Information
WW . . . . . . . Severe Weather Watch Bulletin
07 2 AIM 31/3/15/7110.65R CHG 7/08
Pilot/Controller Glossary 7/31/08
PCG-1
PILOT/CONTROLLER
GLOSSARY
PURPOSE
a. This Glossary was compiled to promote a common understanding of the terms used in the Air Traffic
Control system. It includes those terms which are intended for pilot/controller communications. Those terms
most frequently used in pilot/controller communications are printed in bold italics. The definitions are primarily
defined in an operational sense applicable to both users and operators of the National Airspace System. Use of
the Glossary will preclude any misunderstandings concerning the system's design, function, and purpose.
b. Because of the international nature of flying, terms used in the Lexicon, published by the International
Civil Aviation Organization (ICAO), are included when they differ from FAA definitions. These terms are
followed by “.” For the reader's convenience, there are also cross references to related terms in other parts
of the Glossary and to other documents, such as the Code of Federal Regulations (CFR) and the Aeronautical
Information Manual (AIM).
c. This Glossary will be revised, as necessary, to maintain a common understanding of the system.
EXPLANATION OF CHANGES
a. Terms Added:
AUTOMATIC FLIGHT INFORMATION SERVICE (AFIS) - ALASKA FSS ONLY
b. Editorial/format changes were made where necessary. Revision bars were not used due to the insignificant
nature of the changes.
Pilot/Controller Glossary 2/14/08
PCG A-1
A
AAI(See ARRIVAL AIRCRAFT INTERVAL.)
AAR(See AIRPORT ARRIVAL RATE.)
ABBREVIATED IFR FLIGHT PLANS- An
authorization by ATC requiring pilots to submit only
that information needed for the purpose of ATC. It
includes only a small portion of the usual IFR flight
plan information. In certain instances, this may be
only aircraft identification, location, and pilot
request. Other information may be requested if
needed by ATC for separation/control purposes. It is
frequently used by aircraft which are airborne and
desire an instrument approach or by aircraft which are
on the ground and desire a climb to VFR-on-top.
(See VFR-ON-TOP.)
(Refer to AIM.)
ABEAM- An aircraft is “abeam” a fix, point, or
object when that fix, point, or object is approximately
90 degrees to the right or left of the aircraft track.
Abeam indicates a general position rather than a
precise point.
ABORT- To term inate a preplanned aircraft
maneuver; e.g., an aborted takeoff.
ACC -
(See ICAO term AREA CONTROL CENTER.)
ACCELERATE-STOP DISTANCE AVAILABLE-
The runway plus stopway length declared available
and suitable for the acceleration and deceleration of
an airplane aborting a takeoff.
ACCELERATE-STOP DISTANCE AVAILABLE
- The length of the take-off run available plus
the length of the stopway if provided.
ACDO(See AIR CARRIER DISTRICT OFFICE.)
ACKNOWLEDGE- Let me know that you have
received my message.
(See ICAO term ACKNOWLEDGE.)
ACKNOWLEDGE - Let me know that you
have received and understood this message.
ACL(See AIRCRAFT LIST.)
ACLS(See AUTOMATIC CARRIER LANDING
SYSTEM.)
ACLT(See ACTUAL CALCULATED LANDING TIME.)
ACROBATIC FLIGHT- An intentional maneuver
involving an abrupt change in an aircraft's attitude, an
abnormal attitude, or abnormal acceleration not
necessary for normal flight.
(See ICAO term ACROBATIC FLIGHT.)
(Refer to 14 CFR Part 91.)
ACROBATIC FLIGHT - Maneuvers inten-
tionally performed by an aircraft involving an abrupt
change in its attitude, an abnormal attitude, or an
abnormal variation in speed.
ACTIVE RUNWAY(See RUNWAY IN USE/ACTIVE RUNWAY/DUTY
RUNWAY.)
ACTUAL CALCULATED LANDING TIME-
ACLT is a flight's frozen calculated landing time. An
actual time determined at freeze calculated landing
time (FCLT) or meter list display interval (MLDI) for
the adapted vertex for each arrival aircraft based upon
runway configuration, airport acceptance rate, airport
arrival delay period, and other metered arrival
aircraft. This time is either the vertex time of arrival
(VTA) of the aircraft or the tentative calculated
landing time (TCLT)/ACLT of the previous aircraft
plus the arrival aircraft interval (AAI), whichever is
later. This time will not be updated in response to the
aircraft's progress.
ACTUAL NAVIGATION PERFORMANCE
(ANP)-
(See REQUIRED NAVIGATION
PERFORMANCE.)
ADDITIONAL SERVICES- Advisory information
provided by ATC which includes but is not limited to
the following:
a. Traffic advisories.
b. Vectors, when requested by the pilot, to assist
aircraft receiving traffic advisories to avoid observed
traffic.
Pilot/Controller Glossary 2/14/08
PCG A-2
c. Altitude deviation information of 300 feet or
more from an assigned altitude as observed on a
verified (reading correctly) automatic altitude
readout (Mode C).
d. Advisories that traffic is no longer a factor.
e. Weather and chaff information.
f. Weather assistance.
g. Bird activity information.
h. Holding pattern surveillance. Additional ser-
vices are provided to the extent possible contingent
only upon the controller's capability to fit them into
the performance of higher priority duties and on the
basis of limitations of the radar, volume of traffic,
frequency congestion, and controller workload. The
controller has complete discretion for determining if
he/she is able to provide or continue to provide a
service in a particular case. The controller's reason
not to provide or continue to provide a service in a
particular case is not subject to question by the pilot
and need not be made known to him/her.
(See TRAFFIC ADVISORIES.)
(Refer to AIM.)
ADF(See AUTOMATIC DIRECTION FINDER.)
ADIZ(See AIR DEFENSE IDENTIFICATION ZONE.)
ADLY(See ARRIVAL DELAY.)
ADMINISTRATOR- The Federal Aviation Admin-
istrator or any person to whom he/she has delegated
his/her authority in the matter concerned.
ADR(See AIRPORT DEPARTURE RATE.)
ADS -
(See ICAO term AUTOMATIC DEPENDENT
SURVEILLANCE.)
ADS-B(See AUTOMATIC DEPENDENT
SURVEILLANCE-BROADCAST.)
ADS-C(See AUTOMATIC DEPENDENT
SURVEILLANCE-CONTRACT.)
ADVISE INTENTIONS- Tell me what you plan to
do.
ADVISORY- Advice and information provided to
assist pilots in the safe conduct of flight and aircraft
movement.
(See ADVISORY SERVICE.)
ADVISORY FREQUENCY- The appropriate fre-
quency to be used for Airport Advisory Service.
(See LOCAL AIRPORT ADVISORY.)
(See UNICOM.)
(Refer to ADVISORY CIRCULAR NO. 90-42.)
(Refer to AIM.)
ADVISORY SERVICE- Advice and information
provided by a facility to assist pilots in the safe
conduct of flight and aircraft movement.
(See ADDITIONAL SERVICES.)
(See EN ROUTE FLIGHT ADVISORY
SERVICE.)
(See LOCAL AIRPORT ADVISORY.)
(See RADAR ADVISORY.)
(See SAFETY ALERT.)
(See TRAFFIC ADVISORIES.)
(Refer to AIM.)
AERIAL REFUELING- A procedure used by the
military to transfer fuel from one aircraft to another
during flight.
(Refer to VFR/IFR Wall Planning Charts.)
AERODROME- A defined area on land or water
(including any buildings, installations and equip-
ment) intended to be used either wholly or in part for
the arrival, departure, and movement of aircraft.
AERODROME BEACON - Aeronautical
beacon used to indicate the location of an aerodrome
from the air.
AERODROME CONTROL SERVICE - Air
traffic control service for aerodrome traffic.
AERODROME CONTROL TOWER - A
unit established to provide air traffic control service
to aerodrome traffic.
AERODROME ELEVATION - The eleva-
tion of the highest point of the landing area.
AERODROME TRAFFIC CIRCUIT - The
specified path to be flown by aircraft operating in the
vicinity of an aerodrome.
AERONAUTICAL BEACON- A visual NAVAID
displaying flashes of white and/or colored light to
indicate the location of an airport, a heliport, a
Pilot/Controller Glossary 2/14/08
PCG A-3
landmark, a certain point of a Federal airway in
mountainous terrain, or an obstruction.
(See AIRPORT ROTATING BEACON.)
(Refer to AIM.)
AERONAUTICAL CHART- A map used in air
navigation containing all or part of the following:
topographic features, hazards and obstructions,
navigation aids, navigation routes, designated
airspace, and airports. Commonly used aeronautical
charts are:
a. Sectional Aeronautical Charts (1:500,000)-
Designed for visual navigation of slow or medium
speed aircraft. Topographic information on these
charts features the portrayal of relief and a judicious
selection of visual check points for VFR flight.
Aeronautical information includes visual and radio
aids to navigation, airports, controlled airspace,
restricted areas, obstructions, and related data.
b. VFR Terminal Area Charts (1:250,000)-
Depict Class B airspace which provides for the
control or segregation of all the aircraft within Class
B airspace. The chart depicts topographic informa-
tion and aeronautical information which includes
visual and radio aids to navigation, airports,
controlled airspace, restricted areas, obstructions,
and related data.
c. World Aeronautical Charts (WAC)
(1:1,000,000)- Provide a standard series of aeronau-
tical charts covering land areas of the world at a size
and scale convenient for navigation by moderate
speed aircraft. Topographic information includes
cities and towns, principal roads, railroads, distinc-
tive landmarks, drainage, and relief. Aeronautical
inform ation includes visual and radio aids to
navigation, airports, airways, restricted areas,
obstructions, and other pertinent data.
d. En Route Low Altitude Charts- Provide
aeronautical information for en route instrument
navigation (IF R) in the low altitude stratum.
Information includes the portrayal of airways, limits
of controlled airspace, position identification and
frequencies of radio aids, selected airports, minimum
en route and minimum obstruction clearance
altitudes, airway distances, reporting points, re-
stricted areas, and related data. Area charts, which are
a part of this series, furnish terminal data at a larger
scale in congested areas.
e. En Route High Altitude Charts- Provide
aeronautical information for en route instrument
navigation (IFR) in the high altitude stratum.
Information includes the portrayal of jet routes,
identification and frequencies of radio aids, selected
airports, distances, time zones, special use airspace,
and related information.
f. Instrument Approach Procedures (IAP) Charts-
Portray the aeronautical data which is required to
execute an instrument approach to an airport. These
charts depict the procedures, including all related
data, and the airport diagram. Each procedure is
designated for use with a specific type of electronic
navigation system including NDB, TACAN, VOR,
ILS/MLS, and RNAV. These charts are identified by
the type of navigational aid(s) which provide final
approach guidance.
g. Instrument Departure Procedure (DP) Charts-
Designed to expedite clearance delivery and to
facilitate transition between takeoff and en route
operations. Each DP is presented as a separate chart
and may serve a single airport or more than one
airport in a given geographical location.
h. Standard Terminal Arrival (STAR) Charts-
Designed to expedite air traffic control arrival
procedures and to facilitate transition between en
route and instrument approach operations. Each
STAR procedure is presented as a separate chart and
may serve a single airport or more than one airport in
a given geographical location.
i. Airport Taxi Charts- Designed to expedite the
efficient and safe flow of ground traffic at an airport.
These charts are identified by the official airport
name; e.g., Ronald Reagan Washington National
Airport.
(See ICAO term AERONAUTICAL CHART.)
AERONAUTICAL CHART - A representa-
tion of a portion of the earth, its culture and relief,
specifically designated to meet the requirements of
air navigation.
AERONAUTICAL INFORMATION MANUAL
(AIM)- A primary FAA publication whose purpose
is to instruct airmen about operating in the National
Airspace System of the U.S. It provides basic flight
information, ATC Procedures and general instruc-
tional information concerning health, medical facts,
factors affecting flight safety, accident and hazard
reporting, and types of aeronautical charts and their
use.
AERONAUTICAL INFORMATION PUBLICA-
TION (AIP) - A publication issued by or with
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the authority of a State and containing aeronautical
information of a lasting character essential to air
navigation.
A/FD(See AIRPORT/FACILITY DIRECTORY.)
AFFIRMATIVE- Yes.
AFIS(See AUTOMATIC FLIGHT INFORMATION
SERVICE - ALASKA FSSs ONLY.)
AFP(See AIRSPACE FLOW PROGRAM.)
AIM(See AERONAUTICAL INFORMATION
MANUAL.)
AIP -
(See ICAO term AERONAUTICAL
INFORMATION PUBLICATION.)
AIR CARRIER DISTRICT OFFICE- An FAA field
office serving an assigned geographical area, staffed
with Flight Standards personnel serving the aviation
industry and the general public on matters related to
the certification and operation of scheduled air
carriers and other large aircraft operations.
AIR DEFENSE EMERGENCY- A military emer-
gency condition declared by a designated authority.
This condition exists when an attack upon the
continental U.S., Alaska, Canada, or U.S. installa-
tions in Greenland by hostile aircraft or missiles is
considered probable, is imminent, or is taking place.
(Refer to AIM.)
AIR DEFENSE IDENTIFICATION ZONE (ADIZ)-
The area of airspace over land or water, extending
upward from the surface, within which the ready
identification, the location, and the control of aircraft
are required in the interest of national security.
a. Domestic Air Defense Identification Zone. An
ADIZ within the United States along an international
boundary of the United States.
b. Coastal Air Defense Identification Zone. An
ADIZ over the coastal waters of the United States.
c. Distant Early Warning Identification Zone
(DEWIZ). An ADIZ over the coastal waters of the
State of Alaska.
d. Land-Based Air Defense Identification Zone.
An ADIZ over U.S. metropolitan areas, which is
activated and deactivated as needed, with dimen-
sions, activation dates and other relevant information
disseminated via NOTAM.
Note:_ADIZ locations and operating and flight plan
requirements for civil aircraft operations are speci-
fied in 14 CFR Part 99.
(Refer to AIM.)
AIR NAVIGATION FACILITY- Any facility used
in, available for use in, or designed for use in, aid of
air navigation, including landing areas, lights, any
apparatus or equipment for disseminating weather
information, for signaling, for radio-directional
finding, or for radio or other electrical communica-
tion, and any other structure or mechanism having a
similar purpose for guiding or controlling flight in the
air or the landing and takeoff of aircraft.
(See NAVIGATIONAL AID.)
AIR ROUTE SURVEILLANCE RADAR- Air route
traffic control center (ARTCC) radar used primarily
to detect and display an aircraft's position while en
route between terminal areas. The ARSR enables
controllers to provide radar air traffic control service
when aircraft are within the ARSR coverage. In some
instances, ARSR may enable an ARTCC to provide
terminal radar services similar to but usually more
limited than those provided by a radar approach
control.
AIR ROUTE TRAFFIC CONTROL CENTER- A
facility established to provide air traffic control
service to aircraft operating on IFR flight plans
within controlled airspace and principally during the
en route phase of flight. When equipment capabilities
and controller workload permit, certain advisory/as-
sistance services may be provided to VFR aircraft.
(See EN ROUTE AIR TRAFFIC CONTROL
SERVICES.)
(Refer to AIM.)
AIR TAXI- Used to describe a helicopter/VTOL
aircraft movement conducted above the surface but
normally not above 100 feet AGL. The aircraft may
proceed either via hover taxi or flight at speeds more
than 20 knots. The pilot is solely responsible for
selecting a safe airspeed/altitude for the operation
being conducted.
(See HOVER TAXI.)
(Refer to AIM.)
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AIR TRAFFIC- Aircraft operating in the air or on an
airport surface, exclusive of loading ramps and
parking areas.
(See ICAO term AIR TRAFFIC.)
AIR TRAFFIC - All aircraft in flight or
operating on the maneuvering area of an aerodrome.
AIR TRAFFIC CLEARANCE- An authorization by
air traffic control for the purpose of preventing
collision between known aircraft, for an aircraft to
proceed under specified traffic conditions within
controlled airspace. The pilot-in-command of an
aircraft may not deviate from the provisions of a
visual flight rules (VFR) or instrument flight rules
(IFR) air traffic clearance except in an emergency or
unless an amended clearance has been obtained.
Additionally, the pilot may request a different
clearance from that which has been issued by air
traffic control (ATC) if information available to the
pilot makes another course of action more practicable
or if aircraft equipment limitations or company
procedures forbid compliance with the clearance
issued. Pilots may also request clarification or
amendment, as appropriate, any time a clearance is
not fully understood, or considered unacceptable
because of safety of flight. Controllers should, in
such instances and to the extent of operational
practicality and safety, honor the pilot's request.
14 CFR Part 91.3(a) states: “The pilot in command
of an aircraft is directly responsible for, and is the
final authority as to, the operation of that aircraft.”
THE PILOT IS RESPONSIBLE TO REQUEST AN
AMENDED CLEARANCE if ATC issues a
clearance that would cause a pilot to deviate from a
rule or regulation, or in the pilot's opinion, would
place the aircraft in jeopardy.
(See ATC INSTRUCTIONS.)
(See ICAO term AIR TRAFFIC CONTROL
CLEARANCE.)
AIR TRAFFIC CONTROL- A service operated by
appropriate authority to promote the safe, orderly and
expeditious flow of air traffic.
(See ICAO term AIR TRAFFIC CONTROL
SERVICE.)
AIR TRAFFIC CONTROL CLEARANCE -
Authorization for an aircraft to proceed under
conditions specified by an air traffic control unit.
Note 1:_For convenience, the term air traffic control
clearance is frequently abbreviated to clearance
when used in appropriate contexts.
Note 2:_The abbreviated term clearance may be
prefixed by the words taxi, takeoff, departure, en
route, approach or landing to indicate the particular
portion of flight to which the air traffic control clear-
ance relates.
AIR TRAFFIC CONTROL SERVICE(See AIR TRAFFIC CONTROL.)
AIR TRAFFIC CONTROL SERVICE - A
service provided for the purpose of:
a. Preventing collisions:
1. Between aircraft; and
2. On the maneuvering area between aircraft
and obstructions.
b. Expediting and maintaining an orderly flow of
air traffic.
AIR TRAFFIC CONTROL SPECIALIST- A person
authorized to provide air traffic control service.
(See AIR TRAFFIC CONTROL.)
(See FLIGHT SERVICE STATION.)
(See ICAO term CONTROLLER.)
AIR TRAFFIC CONTROL SYSTEM COMMAND
CENTER (ATCSCC) - An Air Traffic Tactical
Operations facility responsible for monitoring and
managing the flow of air traffic throughout the NAS,
producing a safe, orderly, and expeditious flow of
traffic while minimizing delays. The following
functions are located at the ATCSCC:
a. Central Altitude Reservation Function
(CARF). Responsible for coordinating, planning,
and approving special user requirements under the
Altitude Reservation (ALTRV) concept.
(See ALTITUDE RESERVATION.)
b. Airport Reservation Office (ARO).
Responsible for approving IFR flights at designated
high density traffic airports (John F. Kennedy,
LaGuardia, and Ronald Reagan Washington
National) during specified hours.
(Refer to 14 CFR Part 93.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
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c. U.S. Notice to Airmen (NOTAM) Office.
Responsible for collecting, maintaining, and distrib-
uting NOTAMs for the U.S. civilian and military, as
well as international aviation communities.
(See NOTICE TO AIRMEN.)
d. Weather Unit. Monitor all aspects of weather
for the U.S. that might affect aviation including cloud
cover, visibility, winds, precipitation, thunderstorms,
icing, turbulence, and more. Provide forecasts based
on observations and on discussions with meteorolo-
gists from various National Weather Service offices,
FAA facilities, airlines, and private weather services.
AIR TRAFFIC SERVICE- A generic term meaning:
a. Flight Information Service.
b. Alerting Service.
c. Air Traffic Advisory Service.
d. Air Traffic Control Service:
1. Area Control Service,
2. Approach Control Service, or
3. Airport Control Service.
AIR TRAFFIC SERVICE (ATS) ROUTES - The
term “ATS Route” is a generic term that includes
“VOR Federal airways,” “colored Federal airways,”
“jet routes,” and “RNAV routes.” The term “ATS
route” does not replace these more familiar route
names, but serves only as an overall title when listing
the types of routes that comprise the United States
route structure.
AIRBORNE DELAY- Amount of delay to be
encountered in airborne holding.
AIRCRAFT- Device(s) that are used or intended to
be used for flight in the air, and when used in air traffic
control terminology, may include the flight crew.
(See ICAO term AIRCRAFT.)
AIRCRAFT - Any machine that can derive
support in the atmosphere from the reactions of the air
other than the reactions of the air against the earth's
surface.
AIRCRAFT APPROACH CATEGORY- A
grouping of aircraft based on a speed of 1.3 times the
stall speed in the landing configuration at maximum
gross landing weight. An aircraft must fit in only one
category. If it is necessary to maneuver at speeds in
excess of the upper limit of a speed range for a
category, the minimums for the category for that
speed must be used. For example, an aircraft which
falls in Category A, but is circling to land at a speed
in excess of 91 knots, must use the approach
Category_B minimums when circling to land. The
categories are as follows:
a. Category A- Speed less than 91 knots.
b. Category B- Speed 91 knots or more but less
than 121 knots.
c. Category C- Speed 121 knots or more but less
than 141 knots.
d. Category D- Speed 141 knots or more but less
than 166 knots.
e. Category E- Speed 166 knots or more.
(Refer to 14 CFR Part 97.)
AIRCRAFT CLASSES- For the purposes of Wake
Turbulence Separation Minima, ATC classifies
aircraft as Heavy, Large, and Small as follows:
a. Heavy- Aircraft capable of takeoff weights of
more than 255,000 pounds whether or not they are
operating at this weight during a particular phase of
flight.
b. Large- Aircraft of more than 41,000 pounds,
maximum certificated takeoff weight, up to 255,000
pounds.
c. Small- Aircraft of 41,000 pounds or less
maximum certificated takeoff weight.
(Refer to AIM.)
AIRCRAFT CONFLICT- Predicted conflict, within
URET, of two aircraft, or between aircraft and
airspace. A Red alert is used for conflicts when the
predicted minimum separation is 5 nautical miles or
less. A Yellow alert is used when the predicted
minimum separation is between 5 and approximately
12 nautical miles. A Blue alert is used for conflicts
between an aircraft and predefined airspace.
(See USER REQUEST EVALUATION TOOL.)
AIRCRAFT LIST (ACL)- A view available with
URET that lists aircraft currently in or predicted to be
in a particular sector's airspace. The view contains
textual flight data information in line format and may
be sorted into various orders based on the specific
needs of the sector team.
(See USER REQUEST EVALUATION TOOL.)
AIRCRAFT SURGE LAUNCH AND
RECOVERY- Procedures used at USAF bases to
provide increased launch and recovery rates in
instrument flight rules conditions. ASLAR is based
on:
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a. Reduced separation between aircraft which is
based on time or distance. Standard arrival separation
applies between participants including multiple
flights until the DRAG point. The DRAG point is a
published location on an ASLAR approach where
aircraft landing second in a formation slows to a
predetermined airspeed. The DRAG point is the
reference point at which MARSA applies as
expanding elements effect separation within a flight
or between subsequent participating flights.
b. ASLAR procedures shall be covered in a Letter
of Agreement between the responsible USAF
military ATC facility and the concerned Federal
Aviation Administration facility. Initial Approach
Fix spacing requirements are normally addressed as
a minimum.
AIRMEN'S METEOROLOGICAL
INFORMATION(See AIRMET.)
AIRMET- In-flight weather advisories issued only
to amend the area forecast concerning weather
phenomena which are of operational interest to all
aircraft and potentially hazardous to aircraft having
limited capability because of lack of equipment,
instrumentation, or pilot qualifications. AIRMETs
concern weather of less severity than that covered by
SIGMETs or Convective SIGMETs. AIRMETs
cover moderate icing, moderate turbulence, sustained
winds of 30 knots or more at the surface, widespread
areas of ceilings less than 1,000 feet and/or visibility
less than 3 miles, and extensive mountain
obscurement.
(See AWW.)
(See CONVECTIVE SIGMET.)
(See CWA.)
(See SIGMET.)
(Refer to AIM.)
AIRPORT- An area on land or water that is used or
intended to be used for the landing and takeoff of
aircraft and includes its buildings and facilities, if
any.
AIRPORT ADVISORY AREA- The area within ten
miles of an airport without a control tower or where
the tower is not in operation, and on which a Flight
Service Station is located.
(See LOCAL AIRPORT ADVISORY.)
(Refer to AIM.)
AIRPORT ARRIVAL RATE (AAR)- A dynamic
input parameter specifying the number of arriving
aircraft which an airport or airspace can accept from
the ARTCC per hour. The AAR is used to calculate
the desired interval between successive arrival
aircraft.
AIRPORT DEPARTURE RATE (ADR)- A dynamic
parameter specifying the number of aircraft which
can depart an airport and the airspace can accept per
hour.
AIRPORT ELEVATION- The highest point of an
airport's usable runways measured in feet from mean
sea level.
(See TOUCHDOWN ZONE ELEVATION.)
(See ICAO term AERODROME ELEVATION.)
AIRPORT/FACILITY DIRECTORY- A publication
designed primarily as a pilot's operational manual
containing all airports, seaplane bases, and heliports
open to the public including communications data,
navigational facilities, and certain special notices and
procedures. This publication is issued in seven
volumes according to geographical area.
AIRPORT LIGHTING- Various lighting aids that
may be installed on an airport. Types of airport
lighting include:
a. Approach Light System (ALS)- An airport
lighting facility which provides visual guidance to
landing aircraft by radiating light beam s in a
directional pattern by which the pilot aligns the
aircraft with the extended centerline of the runway on
his/her final approach for landing. Condenser-
Discharge Sequential Flashing Lights/Sequenced
Flashing Lights may be installed in conjunction with
the ALS at some airports. Types of Approach Light
Systems are:
1. ALSF-1- Approach Light System with
Sequenced Flashing Lights in ILS Cat-I configura-
tion.
2. ALSF-2- Approach Light System with
Sequenced Flashing Lights in ILS Cat-II configura-
tion. The ALSF-2 may operate as an SSALR when
weather conditions permit.
3. SSALF- Simplified Short Approach Light
System with Sequenced Flashing Lights.
4. SSALR- Simplified Short Approach Light
System with Runway Alignment Indicator Lights.
5. MALSF- Medium Intensity Approach Light
System with Sequenced Flashing Lights.
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6. MALSR- Medium Intensity Approach Light
System with Runway Alignment Indicator Lights.
7. LDIN- Lead-in-light system- Consists of
one or more series of flashing lights installed at or
near ground level that provides positive visual
guidance along an approach path, either curving or
straight, where special problems exist with hazardous
terrain, obstructions, or noise abatement procedures.
8. RAIL- Runway Alignment Indicator Lights-
Sequenced Flashing Lights which are installed only
in combination with other light systems.
9. ODALS- Omnidirectional Approach Light-
ing System consists of seven omnidirectional
flashing lights located in the approach area of a
nonprecision runway. Five lights are located on the
runway centerline extended with the first light
located 300 feet from the threshold and extending at
equal intervals up to 1,500 feet from the threshold.
The other two lights are located, one on each side of
the runway threshold, at a lateral distance of 40 feet
from the runway edge, or 75 feet from the runway
edge when installed on a runway equipped with a
VASI.
(Refer to FAAO JO 6850.2, VISUAL GUIDANCE
LIGHTING SYSTEMS.)
b. Runway Lights/Runway Edge Lights- Lights
having a prescribed angle of emission used to define
the lateral limits of a runway. Runway lights are
uniformly spaced at intervals of approximately 200
feet, and the intensity may be controlled or preset.
c. Touchdown Zone Lighting- Two rows of
transverse light bars located symmetrically about the
runway centerline normally at 100 foot intervals. The
basic system extends 3,000 feet along the runway.
d. Runway Centerline Lighting- Flush centerline
lights spaced at 50-foot intervals beginning 75 feet
from the landing threshold and extending to within 75
feet of the opposite end of the runway.
e. Threshold Lights- Fixed green lights arranged
symmetrically left and right of the runway centerline,
identifying the runway threshold.
f. Runway End Identifier Lights (REIL)- Two
synchronized flashing lights, one on each side of the
runway threshold, which provide rapid and positive
identification of the approach end of a particular
runway.
g. Visual Approach Slope Indicator (VASI)- An
airport lighting facility providing vertical visual
approach slope guidance to aircraft during approach
to landing by radiating a directional pattern of high
intensity red and white focused light beams which
indicate to the pilot that he/she is “on path” if he/she
sees red/white, “above path” if white/white, and
“below path” if red/red. Some airports serving large
aircraft have three-bar VASIs which provide two
visual glide paths to the same runway.
h. Precision Approach Path Indicator (PAPI)- An
airport lighting facility, similar to VASI, providing
vertical approach slope guidance to aircraft during
approach to landing. PAPIs consist of a single row of
either two or four lights, normally installed on the left
side of the runway, and have an effective visual range
of about 5 miles during the day and up to 20 miles at
night. PAPIs radiate a directional pattern of high
intensity red and white focused light beams which
indicate that the pilot is “on path” if the pilot sees an
equal number of white lights and red lights, with
white to the left of the red; “above path” if the pilot
sees more white than red lights; and “below path” if
the pilot sees more red than white lights.
i. Boundary Lights- Lights defining the perimeter
of an airport or landing area.
(Refer to AIM.)
AIRPORT MARKING AIDS- Markings used on
runway and taxiway surfaces to identify a specific
runway, a runway threshold, a centerline, a hold line,
etc. A runway should be marked in accordance with
its present usage such as:
a. Visual.
b. Nonprecision instrument.
c. Precision instrument.
(Refer to AIM.)
AIR PORT REFERENCE POINT (ARP)- The
approximate geometric center of all usable runway
surfaces.
AIRPORT RESERVATION OFFICE- Office re-
sponsible for monitoring the operation of the high
density rule. Receives and processes requests for
IFR-operations at high density traffic airports.
AIRPORT ROTATING BEACON- A visual
NAVAID operated at many airports. At civil airports,
alternating white and green flashes indicate the
location of the airport. At military airports, the
beacons flash alternately white and green, but are
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differentiated from civil beacons by dualpeaked (two
quick) white flashes between the green flashes.
(See INSTRUMENT FLIGHT RULES.)
(See SPECIAL VFR OPERATIONS.)
(See ICAO term AERODROME BEACON.)
(Refer to AIM.)
AIRPORT STREAM FILTER (ASF)- An on/off
filter that allows the conflict notification function to
be inhibited for arrival streams into single or multiple
airports to prevent nuisance alerts.
AIRPORT SURFACE DETECTION EQUIPMENT
(ASDE)- Surveillance equipment specifically de-
signed to detect aircraft, vehicular traffic, and other
objects, on the surface of an airport, and to present the
image on a tower display. Used to augment visual
observation by tower personnel of aircraft and/or
vehicular movements on runways and taxiways.
There are three ASDE systems deployed in the NAS:
a. ASDE-3- a Surface Movement Radar.
b. ASDE-X- a system that uses a X-band Surface
Movement Radar and multilateration. Data from
these two sources are fused and presented on a digital
display.
c. ASDE-3X- an ASDE-X system that uses the
ASDE-3 Surface Movement Radar.
AIRPORT SURVEILLANCE RADAR- Approach
control radar used to detect and display an aircraft's
position in the terminal area. ASR provides range and
azimuth information but does not provide elevation
data. Coverage of the ASR can extend up to 60 miles.
AIRPORT TAXI CHARTS(See AERONAUTICAL CHART.)
AIRPORT TRAFFIC CONTROL SERVICE- A
service provided by a control tower for aircraft
operating on the movement area and in the vicinity of
an airport.
(See MOVEMENT AREA.)
(See TOWER.)
(See ICAO term AERODROME CONTROL
SERVICE.)
AIRPORT TRAFFIC CONTROL TOWER(See TOWER.)
AIRSPACE CONFLICT- Predicted conflict of an
aircraft and active Special Activity Airspace (SAA).
AIRSPACE FLOW PROGRAM (AFP)- AFP is a
Traffic Management (TM) process administered by
the Air Traffic Control System Command Center
(ATCSCC) where aircraft are assigned an Expect
Departure Clearance Time (EDCT) in order to
manage capacity and demand for a specific area of the
National Airspace System (NAS). The purpose of the
program is to mitigate the effects of en route
constraints. It is a flexible program and may be
implemented in various forms depending upon the
needs of the air traffic system.
AIRSPACE HIERARCHY- Within the airspace
classes, there is a hierarchy and, in the event of an
overlap of airspace: Class A preempts Class B, Class
B preempts Class C, Class C preempts Class D, Class
D preempts Class E, and Class E preempts Class G.
AIRSPEED- The speed of an aircraft relative to its
surrounding air mass. The unqualified term
“airspeed” means one of the following:
a. Indicated Airspeed- The speed shown on the
aircraft airspeed indicator. This is the speed used in
pilot/controller communications under the general
term “airspeed.”
(Refer to 14 CFR Part 1.)
b. True Airspeed- The airspeed of an aircraft
relative to undisturbed air. Used primarily in flight
planning and en route portion of flight. When used in
pilot/controller communications, it is referred to as
“true airspeed” and not shortened to “airspeed.”
AIRSTART- The starting of an aircraft engine while
the aircraft is airborne, preceded by engine shutdown
during training flights or by actual engine failure.
AIRWAY- A Class E airspace area established in the
form of a corridor, the centerline of which is defined
by radio navigational aids.
(See FEDERAL AIRWAYS.)
(See ICAO term AIRWAY.)
(Refer to 14 CFR Part 71.)
(Refer to AIM.)
AIRWAY - A control area or portion thereof
established in the form of corridor equipped with
radio navigational aids.
AIRWAY BEACON- Used to mark airway segments
in remote mountain areas. The light flashes Morse
Code to identify the beacon site.
(Refer to AIM.)
AIT(See AUTOMATED INFORMATION
TRANSFER.)
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ALERFA (Alert Phase) - A situation wherein
apprehension exists as to the safety of an aircraft and
its occupants.
ALERT- A notification to a position that there
is an aircraft-to-aircraft or aircraft-to-airspace
conflict, as detected by Automated Problem
Detection (APD).
ALERT AREA(See SPECIAL USE AIRSPACE.)
ALERT NOTICE- A request originated by a flight
service station (FSS) or an air route traffic control
center (ARTCC) for an extensive communication
search for overdue, unreported, or missing aircraft.
ALERTING SERVICE- A service provided to notify
appropriate organizations regarding aircraft in need
of search and rescue aid and assist such organizations
as required.
ALNOT(See ALERT NOTICE.)
ALONG-TRACK DISTANCE (ATD)- The distance
measured from a point-in-space by systems using
area navigation reference capabilities that are not
subject to slant range errors.
ALPHANUMERIC DISPLAY- Letters and numer-
als used to show identification, altitude, beacon code,
and other information concerning a target on a radar
display.
(See AUTOMATED RADAR TERMINAL
SYSTEMS.)
ALTERNATE AERODROME - An aero-
drome to which an aircraft may proceed when it
becomes either impossible or inadvisable to proceed
to or to land at the aerodrome of intended landing.
Note:_The aerodrome from which a flight departs
may also be an en-route or a destination alternate
aerodrome for the flight.
ALTERNATE AIRPORT- An airport at which an
aircraft may land if a landing at the intended airport
becomes inadvisable.
(See ICAO term ALTERNATE AERODROME.)
ALTIMETER SETTING- The barometric pressure
reading used to adjust a pressure altimeter for
variations in existing atmospheric pressure or to the
standard altimeter setting (29.92).
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
ALTITUDE- The height of a level, point, or object
measured in feet Above Ground Level (AGL) or from
Mean Sea Level (MSL).
(See FLIGHT LEVEL.)
a. MSL Altitude- Altitude expressed in feet
measured from mean sea level.
b. AGL Altitude- Altitude expressed in feet
measured above ground level.
c. Indicated Altitude- The altitude as shown by an
altimeter. On a pressure or barometric altimeter it is
altitude as shown uncorrected for instrument error
and uncompensated for variation from standard
atmospheric conditions.
(See ICAO term ALTITUDE.)
ALTITUDE - The vertical distance of a level,
a point or an object considered as a point, measured
from mean sea level (MSL).
ALTITUDE READOUT- An aircraft's altitude,
transmitted via the Mode C transponder feature, that
is visually displayed in 100-foot increments on a
radar scope having readout capability.
(See ALPHANUMERIC DISPLAY.)
(See AUTOMATED RADAR TERMINAL
SYSTEMS.)
(Refer to AIM.)
ALTITUDE RESERVATION- Airspace utilization
under prescribed conditions normally employed for
the mass movement of aircraft or other special user
requirem ents which cannot otherwise be
accomplished. ALTRVs are approved by the
appropriate FAA facility.
(See AIR TRAFFIC CONTROL SYSTEM
COMMAND CENTER.)
ALTITUDE RESTRICTION- An altitude or alti-
tudes, stated in the order flown, which are to be
maintained until reaching a specific point or time.
Altitude restrictions may be issued by ATC due to
traffic, terrain, or other airspace considerations.
ALTITUDE RESTRICTIONS ARE CANCELED-
Adherence to previously imposed altitude restric-
tions is no longer required during a climb or descent.
ALTRV(See ALTITUDE RESERVATION.)
AMVER(See AUTOMATED MUTUAL-ASSISTANCE
VESSEL RESCUE SYSTEM.)
APB(See AUTOMATED PROBLEM DETECTION
BOUNDARY.)
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG A-11
APD(See AUTOMATED PROBLEM DETECTION.)
APDIA(See AUTOMATED PROBLEM DETECTION
INHIBITED AREA.)
APPROACH CLEARANCE- Authorization by
ATC for a pilot to conduct an instrument approach.
The type of instrum ent approach for which a
clearance and other pertinent information is provided
in the approach clearance when required.
(See CLEARED APPROACH.)
(See INSTRUMENT APPROACH
PROCEDURE.)
(Refer to AIM.)
(Refer to 14 CFR Part 91.)
APPROACH CONTROL FACILITY- A terminal
ATC facility that provides approach control service in
a terminal area.
(See APPROACH CONTROL SERVICE.)
(See RADAR APPROACH CONTROL
FACILITY.)
APPROACH CONTROL SERVICE- Air traffic
control service provided by an approach control
facility for arriving and departing VFR/IFR aircraft
and, on occasion, en route aircraft. At some airports
not served by an approach control facility, the
ARTCC provides limited approach control service.
(See ICAO term APPROACH CONTROL
SERVICE.)
(Refer to AIM.)
APPROACH CONTROL SERVICE - Air
traffic control service for arriving or departing
controlled flights.
APPROACH GATE- An imaginary point used
within ATC as a basis for vectoring aircraft to the
final approach course. The gate will be established
along the final approach course 1 mile from the final
approach fix on the side away from the airport and
will be no closer than 5 miles from the landing
threshold.
APPROACH LIGHT SYSTEM(See AIRPORT LIGHTING.)
APPROACH SEQUENCE- The order in which
aircraft are positioned while on approach or awaiting
approach clearance.
(See LANDING SEQUENCE.)
(See ICAO term APPROACH SEQUENCE.)
APPROACH SEQUENCE - The order in
which two or more aircraft are cleared to approach to
land at the aerodrome.
APPROACH SPEED- The recommended speed
contained in aircraft manuals used by pilots when
making an approach to landing. This speed will vary
for different segments of an approach as well as for
aircraft weight and configuration.
APPROPRIATE ATS AUTHORITY - The
relevant authority designated by the State responsible
for providing air traffic services in the airspace
concerned. In the United States, the “appropriate ATS
authority” is the Program Director for Air Traffic
Planning and Procedures, ATP-1.
APPROPRIATE AUTHORITYa. Regarding flight over the high seas: the relevant
authority is the State of Registry.
b. Regarding flight over other than the high seas:
the relevant authority is the State having sovereignty
over the territory being overflown.
APPROPRIATE OBSTACLE CLEARANCE
MINIMUM ALTITUDE- Any of the following:
(See MINIMUM EN ROUTE IFR ALTITUDE.)
(See MINIMUM IFR ALTITUDE.)
(See MINIMUM OBSTRUCTION CLEARANCE
ALTITUDE.)
(See MINIMUM VECTORING ALTITUDE.)
APPROPRIATE TERRAIN CLEARANCE
MINIMUM ALTITUDE- Any of the following:
(See MINIMUM EN ROUTE IFR ALTITUDE.)
(See MINIMUM IFR ALTITUDE.)
(See MINIMUM OBSTRUCTION CLEARANCE
ALTITUDE.)
(See MINIMUM VECTORING ALTITUDE.)
APRON- A defined area on an airport or heliport
intended to accommodate aircraft for purposes of
loading or unloading passengers or cargo, refueling,
parking, or maintenance. With regard to seaplanes, a
ramp is used for access to the apron from the water.
(See ICAO term APRON.)
APRON - A defined area, on a land
aerodrome, intended to accommodate aircraft for
purposes of loading or unloading passengers, mail or
cargo, refueling, parking or maintenance.
ARC- The track over the ground of an aircraft flying
at a constant distance from a navigational aid by
reference to distance measuring equipment (DME).
7/31/08 Pilot/Controller Glossary
2/14/08
PCG A-12
AREA CONTROL CENTER - An air traffic
control facility primarily responsible for ATC
services being provided IFR aircraft during the en
route phase of flight. The U.S. equivalent facility is
an air route traffic control center (ARTCC).
AREA NAVIGATION- Area Navigation (RNAV)
provides enhanced navigational capability to the
pilot. RNAV equipment can compute the airplane
position, actual track and ground speed and then
provide meaningful information relative to a route of
flight selected by the pilot. Typical equipment will
provide the pilot with distance, time, bearing and
crosstrack error relative to the selected “TO” or
“active” waypoint and the selected route. Several
distinctly different navigational systems with
different navigational performance characteristics
are capable of providing area navigational functions.
Present day RNAV includes INS, LORAN, VOR/
DME, and GPS systems. Modern multi-sensor
systems can integrate one or more of the above
systems to provide a more accurate and reliable
navigational system. Due to the different levels of
performance, area navigational capabilities can
satisfy different levels of required navigational
performance (RNP). The major types of equipment
are:
a. VORTAC referenced or Course Line Computer
(CLC) systems, which account for the greatest
number of RNAV units in use. To function, the CLC
must be within the service range of a VORTAC.
b. OMEGA/VLF, although two separate systems,
can be considered as one operationally. A long-range
navigation system based upon Very Low Frequency
radio signals transmitted from a total of 17 stations
worldwide.
c. Inertial (INS) systems, which are totally
self-contained and require no information from
external references. They provide aircraft position
and navigation information in response to signals
resulting from inertial effects on components within
the system.
d. MLS Area Navigation (MLS/RNAV), which
provides area navigation with reference to an MLS
ground facility.
e. LORAN-C is a long-range radio navigation
system that uses ground waves transmitted at low
frequency to provide user position information at
ranges of up to 600 to 1,200 nautical miles at both en
route and approach altitudes. The usable signal
coverage areas are determined by the signal-to-noise
ratio, the envelope-to-cycle difference, and the
geometric relationship between the positions of the
user and the transmitting stations.
