|
4-1-1.
Air Route Traffic Control Centers
Centers are established
primarily to provide air traffic service to aircraft
operating on IFR flight plans within controlled
airspace, and principally during the en route phase of
flight.
4-1-2.
Control Towers
Towers have been
established to provide for a safe, orderly and
expeditious flow of traffic on and in the vicinity of an
airport. When the responsibility has been so delegated,
towers also provide for the separation of IFR aircraft
in the terminal areas.
REFERENCE-
AIM, Approach Control, Paragraph 5-4-3.

4-1-3.
Flight Service Stations
a.
Flight Service Stations (FSS's) are air
traffic facilities which provide pilot briefings, en
route communications and VFR search and rescue
services, assist lost aircraft and aircraft in
emergency situations, relay ATC clearances, originate
Notices to Airmen, broadcast aviation weather and
National Airspace System (NAS) information, receive
and process IFR flight plans, and monitor navigational
aids (NAVAID's). In addition, at selected locations
FSS's provide En Route Flight Advisory Service (Flight
Watch), take weather observations, issue airport
advisories, and advise Customs and Immigration of
transborder flights.
b.
Supplemental Weather Service Locations
(SWSL's) are airport facilities staffed with contract
personnel who take weather observations and provide
current local weather to pilots via telephone or
radio. All other services are provided by the parent
FSS.

4-1-4.
Recording and Monitoring
a.
Calls to air traffic control (ATC)
facilities (ARTCC's, Towers, FSS's, Central Flow, and
Operations Centers) over radio and ATC operational
telephone lines (lines used for operational purposes
such as controller instructions, briefings, opening
and closing flight plans, issuance of IFR clearances
and amendments, counter hijacking activities, etc.)
may be monitored and recorded for operational uses
such as accident investigations, accident prevention,
search and rescue purposes, specialist training and
evaluation, and technical evaluation and repair of
control and communications systems.
b.
Where the public access telephone is
recorded, a beeper tone is not required. In place of
the "beep" tone the FCC has substituted a mandatory
requirement that persons to be recorded be given
notice they are to be recorded and give consent.
Notice is given by this entry, consent to record is
assumed by the individual placing a call to the
operational facility.

4-1-5.
Communications Release of IFR Aircraft Landing at an
Airport Without an Operating Control Tower
Aircraft operating on an
IFR flight plan, landing at an airport without an
operating control tower will be advised to change to the
airport advisory frequency when direct communications
with ATC are no longer required. Towers and centers do
not have nontower airport traffic and runway in use
information. The instrument approach may not be aligned
with the runway in use; therefore, if the information
has not already been obtained, pilots should make an
expeditious change to the airport advisory frequency
when authorized.
REFERENCE-
AIM, Advance Information on Instrument Approach,
Paragraph 5-4-4.

4-1-6.
Pilot Visits to Air Traffic Facilities
Pilots are encouraged to
visit air traffic facilities (Towers, Centers and FSS's)
and familiarize themselves with the ATC system. On rare
occasions, facilities may not be able to approve a visit
because of ATC workload or other reasons. It is,
therefore, requested that pilots contact the facility
prior to the visit and advise of the number of persons
in the group, the time and date of the proposed visit
and the primary interest of the group. With this
information available, the facility can prepare an
itinerary and have someone available to guide the group
through the facility.
4-1-7.
Operation Take-off and Operation Raincheck
Operation Take-off is a
program that educates pilots in how best to utilize the
FSS modernization efforts and services available in
Automated Flight Service Stations (AFSS), as stated in
FAA Order 7230.17, Pilot Education Program - Operation
Takeoff. Operation Raincheck is a program designed to
familiarize pilots with the ATC system, its functions,
responsibilities and benefits.

4-1-8. Approach
Control Service for VFR Arriving Aircraft
a.
Numerous approach control facilities
have established programs for arriving VFR aircraft to
contact approach control for landing information. This
information includes: wind, runway, and altimeter
setting at the airport of intended landing. This
information may be omitted if contained in the
Automatic Terminal Information Service (ATIS)
broadcast and the pilot states the appropriate ATIS
code.
NOTE-
Pilot use of "have numbers" does not indicate receipt
of the ATIS broadcast. In addition, the controller
will provide traffic advisories on a workload
permitting basis.
b.
Such information will be furnished upon
initial contact with concerned approach control
facility. The pilot will be requested to change to the
tower frequency at a predetermined time or
point, to receive further landing information.
c.
Where available, use of this procedure
will not hinder the operation of VFR flights by
requiring excessive spacing between aircraft or
devious routing.
d.
Compliance with this procedure is not
mandatory but pilot participation is encouraged.
REFERENCE-
AIM, Terminal Radar Services for VFR Aircraft,
Paragraph
4-1-17.
NOTE-
Approach control services for VFR aircraft are
normally dependent on ATC radar. These services are
not available during periods of a radar outage.
Approach control services for VFR aircraft are limited
when CENRAP is in use.

4-1-9. Traffic
Advisory Practices at Airports Without Operating Control
Towers
(See TBL 4-1-1.)
a. Airport
Operations Without Operating Control Tower
1.
There is no substitute for alertness
while in the vicinity of an airport. It is essential
that pilots be alert and look for other traffic and
exchange traffic information when approaching or
departing an airport without an operating control
tower. This is of particular importance since other
aircraft may not have communication capability or,
in some cases, pilots may not communicate their
presence or intentions when operating into or out of
such airports. To achieve the greatest degree of
safety, it is essential that all radio-equipped
aircraft transmit/receive on a common frequency
identified for the purpose of airport advisories.
2.
An airport may have a full or
part-time tower or FSS located on the airport, a
full or part-time UNICOM station or no aeronautical
station at all. There are three ways for pilots to
communicate their intention and obtain
airport/traffic information when operating at an
airport that does not have an operating tower: by
communicating with an FSS, a UNICOM operator, or by
making a self-announce broadcast.
3.
Many airports are now providing
completely automated weather, radio check capability
and airport advisory information on an automated
UNICOM system. These systems offer a variety of
features, typically selectable by microphone clicks,
on the UNICOM frequency. Availability of the
automated UNICOM will be published in the
Airport/Facility Directory and approach charts.
b. Communicating on
a Common Frequency
1.
The key to communicating at an
airport without an operating control tower is
selection of the correct common frequency. The
acronym CTAF which stands for Common Traffic
Advisory Frequency, is synonymous with this program.
A CTAF is a frequency designated for the purpose of
carrying out airport advisory practices while
operating to or from an airport without an operating
control tower. The CTAF may be a UNICOM, MULTICOM,
FSS, or tower frequency and is identified in
appropriate aeronautical publications.
TBL 4-1-1
Summary of Recommended
Communication Procedures
|
|
|
|
Communication/Broadcast Procedures
|
|
|
Facility at Airport
|
Frequency Use
|
Outbound
|
Inbound
|
Practice
Instrument
Approach |
|
1. |
UNICOM (No Tower or
FSS) |
Communicate with
UNICOM station on published CTAF frequency (122.7;
122.8; 122.725; 122.975; or 123.0). If unable to
contact UNICOM station, use self-announce
procedures on CTAF. |
Before taxiing and
before taxiing on the runway for departure.
|
10 miles out.
Entering downwind, base, and final. Leaving the
runway. |
|
|
2. |
No Tower, FSS, or
UNICOM |
Self-announce on
MULTICOM frequency 122.9. |
Before taxiing and
before taxiing on the runway for departure.
|
10 miles out.
Entering downwind, base, and final. Leaving the
runway. |
Departing final
approach fix (name) or on final approach segment
inbound. |
|
3. |
No Tower in
operation, FSS open |
Communicate with
FSS on CTAF frequency. |
Before taxiing and
before taxiing on the runway for departure.
|
10 miles out.
Entering downwind, base, and final. Leaving the
runway. |
Approach completed/
terminated. |
|
4. |
FSS Closed (No
Tower) |
Self-announce on
CTAF. |
Before taxiing and
before taxiing on the runway for departure.
|
10 miles out.
Entering downwind, base, and final. Leaving the
runway. |
|
|
5. |
Tower or FSS not in
operation |
Self-announce on
CTAF. |
Before taxiing and
before taxiing on the runway for departure.
|
10 miles out.
Entering downwind, base, and final. Leaving the
runway. |
|
2. The CTAF frequency for
a particular airport is contained in the A/FD,
Alaska Supplement, Alaska Terminal Publication,
Instrument Approach Procedure Charts, and Instrument
Departure Procedure (DP) Charts. Also, the CTAF
frequency can be obtained by contacting any FSS. Use
of the appropriate CTAF, combined with a visual
alertness and application of the following
recommended good operating practices, will enhance
safety of flight into and out of all uncontrolled
airports.
c. Recommended
Traffic Advisory Practices
1.
Pilots of inbound traffic should
monitor and communicate as appropriate on the
designated CTAF from 10 miles to landing. Pilots of
departing aircraft should monitor/communicate on the
appropriate frequency from start-up, during taxi,
and until 10 miles from the airport unless the CFR's
or local procedures require otherwise.
2.
Pilots of aircraft conducting other
than arriving or departing operations at altitudes
normally used by arriving and departing aircraft
should monitor/communicate on the appropriate
frequency while within 10 miles of the airport
unless required to do otherwise by the CFR's or
local procedures. Such operations include parachute
jumping/dropping, en route, practicing maneuvers,
etc.
REFERENCE-
AIM, Parachute Jump Aircraft Operations, Paragraph
3-5-4.
d. Airport
Advisory/Information Services Provided by a FSS
1.
There are three advisory type
services provided at selected airports.
(a)
Local Airport Advisory (LAA) is
provided at airports that have a FSS physically
located on the airport, which does not have a
control tower or where the tower is operated on a
part-time basis. The CTAF for LAA airports is
disseminated in the appropriate aeronautical
publications.
(b)
Remote Airport Advisory (RAA) is
provided at selected very busy GA airports, which
do not have an operating control tower. The CTAF
for RAA airports is disseminated in the
appropriate aeronautical publications.
(c)
Remote Airport Information Service
(RAIS) is provided in support of special events at
nontowered airports by request from the airport
authority.
2.
In communicating with a CTAF FSS,
check the airport's automated weather and establish
two-way communications before transmitting
outbound/inbound intentions or information. An
inbound aircraft should initiate contact
approximately 10 miles from the airport, reporting
aircraft identification and type, altitude, location
relative to the airport, intentions (landing or over
flight), possession of the automated weather, and
request airport advisory or airport information
service. A departing aircraft should initiate
contact before taxiing, reporting aircraft
identification and type, VFR or IFR, location on the
airport, intentions, direction of take-off,
possession of the automated weather, and request
airport advisory or information service. Also,
report intentions before taxiing onto the active
runway for departure. If you must change frequencies
for other service after initial report to FSS,
return to FSS frequency for traffic update.
(a)
Inbound
EXAMPLE-
Vero Beach radio, Centurion Six Niner Delta Delta
is ten miles south, two thousand, landing Vero
Beach. I have the automated weather, request
airport advisory.
(b)
Outbound
EXAMPLE-
Vero Beach radio, Centurion Six Niner Delta Delta,
ready to taxi to runway 22, VFR, departing to the
southwest. I have the automated weather, request
airport advisory.
3.
Airport advisory service includes
wind direction and velocity, favored or designated
runway, altimeter setting, known airborne and ground
traffic, NOTAM's, airport taxi routes, airport
traffic pattern information, and instrument approach
procedures. These elements are varied so as to best
serve the current traffic situation. Some airport
managers have specified that under certain wind or
other conditions designated runways be used. Pilots
should advise the FSS of the runway they intend to
use.
CAUTION-
All aircraft in the vicinity of an airport may not
be in communication with the FSS.
e. Information
Provided by Aeronautical Advisory Stations (UNICOM)
1.
UNICOM is a nongovernment air/ground
radio communication station which may provide
airport information at public use airports where
there is no tower or FSS.
2.
On pilot request, UNICOM stations may
provide pilots with weather information, wind
direction, the recommended runway, or other
necessary information. If the UNICOM frequency is
designated as the CTAF, it will be identified in
appropriate aeronautical publications.
f. Unavailability of
Information from FSS or UNICOM
Should LAA by an FSS or
Aeronautical Advisory Station UNICOM be unavailable,
wind and weather information may be obtainable from
nearby controlled airports via Automatic Terminal
Information Service (ATIS) or Automated Weather
Observing System (AWOS) frequency.
g. Self-Announce
Position and/or Intentions
1. General.
Self-announce is a
procedure whereby pilots broadcast their position or
intended flight activity or ground operation on the
designated CTAF. This procedure is used primarily at
airports which do not have an FSS on the airport.
The self-announce procedure should also be used if a
pilot is unable to communicate with the FSS on the
designated CTAF.
2.
If an airport has a tower and it is
temporarily closed, or operated on a part-time basis
and there is no FSS on the airport or the FSS is
closed, use the CTAF to self-announce your position
or intentions.
3.
Where there is no tower, FSS, or
UNICOM station on the airport, use MULTICOM
frequency 122.9 for self-announce procedures. Such
airports will be identified in appropriate
aeronautical information publications.
4. Practice
Approaches.
Pilots
conducting practice instrument approaches should be
particularly alert for other aircraft that may be
departing in the opposite direction. When conducting
any practice approach, regardless of its direction
relative to other airport operations, pilots should
make announcements on the CTAF as follows:
(a)
Departing the final approach fix,
inbound (nonprecision approach) or departing the
outer marker or fix used in lieu of the outer
marker, inbound (precision approach);
(b)
Established on the final approach
segment or immediately upon being released by ATC;
(c)
Upon completion or termination of
the approach; and
(d)
Upon executing the missed approach
procedure.
5.
Departing aircraft should always be
alert for arrival aircraft coming from the opposite
direction.
6.
Recommended self-announce
phraseologies: It should be noted that aircraft
operating to or from another nearby airport may be
making self-announce broadcasts on the same UNICOM
or MULTICOM frequency. To help identify one airport
from another, the airport name should be spoken at
the beginning and end of each self-announce
transmission.
(a)
Inbound
EXAMPLE-
Strawn traffic, Apache Two Two Five Zulu,
(position), (altitude), (descending) or entering
downwind/base/final (as appropriate) runway one
seven full stop, touch-and-go, Strawn.
Strawn traffic Apache Two Two Five Zulu clear of
runway one seven Strawn.
(b)
Outbound
EXAMPLE-
Strawn traffic, Queen Air Seven One Five Five
Bravo (location on airport) taxiing to runway two
six Strawn.
Strawn traffic, Queen Air Seven One Five Five
Bravo departing runway two six. Departing the
pattern to the (direction), climbing to (altitude)
Strawn.
(c)
Practice Instrument Approach
EXAMPLE-
Strawn traffic, Cessna Two One Four Three Quebec
(position from airport) inbound descending through
(altitude) practice (name of approach) approach
runway three five Strawn.
Strawn traffic, Cessna Two One Four Three Quebec
practice (type) approach completed or terminated
runway three five Strawn.
h. UNICOM
Communications Procedures
1.
In communicating with a UNICOM
station, the following practices will help reduce
frequency congestion, facilitate a better
understanding of pilot intentions, help identify the
location of aircraft in the traffic pattern, and
enhance safety of flight:
(a)
Select the correct UNICOM
frequency.
(b)
State the identification of the
UNICOM station you are calling in each
transmission.
(c)
Speak slowly and distinctly.
(d)
Report approximately 10 miles from
the airport, reporting altitude, and state your
aircraft type, aircraft identification, location
relative to the airport, state whether landing or
overflight, and request wind information and
runway in use.
(e)
Report on downwind, base, and final
approach.
(f)
Report leaving the runway.
2.
Recommended UNICOM phraseologies:
(a)
Inbound
PHRASEOLOGY-
FREDERICK UNICOM CESSNA EIGHT ZERO ONE TANGO
FOXTROT 10 MILES SOUTHEAST DESCENDING THROUGH
(altitude) LANDING FREDERICK, REQUEST WIND AND
RUNWAY INFORMATION FREDERICK.
FREDERICK TRAFFIC CESSNA EIGHT ZERO ONE TANGO
FOXTROT ENTERING DOWNWIND/BASE/ FINAL (as
appropriate) FOR RUNWAY ONE NINER (full
stop/touch-and-go) FREDERICK.
FREDERICK TRAFFIC CESSNA EIGHT ZERO ONE TANGO
FOXTROT CLEAR OF RUNWAY ONE NINER FREDERICK.
(b)
Outbound
PHRASEOLOGY-
FREDERICK UNICOM CESSNA EIGHT ZERO ONE TANGO
FOXTROT (location on airport) TAXIING TO RUNWAY
ONE NINER, REQUEST WIND AND TRAFFIC INFORMATION
FREDERICK.
FREDERICK TRAFFIC CESSNA EIGHT ZERO ONE TANGO
FOXTROT DEPARTING RUNWAY ONE NINER. "REMAINING IN
THE PATTERN" OR "DEPARTING THE PATTERN TO THE
(direction) (as appropriate)" FREDERICK.

4-1-10. IFR Approaches/Ground
Vehicle Operations
a. IFR Approaches.
When operating in accordance
with an IFR clearance and ATC approves a change to the
advisory frequency, make an expeditious change to the
CTAF and employ the recommended traffic advisory
procedures.
b. Ground Vehicle
Operation. Airport ground
vehicles equipped with radios should monitor the CTAF
frequency when operating on the airport movement area
and remain clear of runways/taxiways being used by
aircraft. Radio transmissions from ground vehicles
should be confined to safety-related matters.
c. Radio Control of
Airport Lighting Systems.
Whenever possible, the CTAF will be used to control
airport lighting systems at airports without operating
control towers. This eliminates the need for pilots to
change frequencies to turn the lights on and allows a
continuous listening watch on a single frequency. The
CTAF is published on the instrument approach chart and
in other appropriate aeronautical information
publications. For further details concerning radio
controlled lights, see AC 150/5340-27, Air-to-Ground
Radio Control of Airport Lighting Systems.

4-1-11. Designated UNICOM/MULTICOM
Frequencies
a. Communications
between aircraft
CAUTION-
The Federal Communications Commission (FCC) requires
an aircraft station license to operate on UNICOM/MULTICOM
frequencies and usage must be in accordance with Part
87 of the FCC rules (see Section 87.29 regarding
license applications). Misuse of these frequencies may
result in either the imposition of fines and/or
revocation/suspension of FCC aircraft station license.
b. Frequency use
1.
The following listing depicts UNICOM
and MULTICOM frequency uses as designated by the
Federal Communications Commission (FCC). (See TBL
4-1-2.)
TBL 4-1-2
Unicom/Multicom Frequency
Usage
|
Use
|
Frequency
|
|
Airports without an
operating control tower. |
122.700
122.725
122.800
122.975
123.000
123.050
123.075 |
|
(MULTICOM
FREQUENCY) Activities of a temporary, seasonal,
emergency nature or search and rescue, as well as,
airports with no tower, FSS, or UNICOM.
|
122.900
|
|
(MULTICOM
FREQUENCY) Forestry management and fire
suppression, fish and game management and
protection, and environmental monitoring and
protection. |
122.925
|
|
Airports with a
control tower or FSS on airport. |
122.950
|
NOTE-
1. In some areas
of the country, frequency interference may be
encountered from nearby airports using the same
UNICOM frequency. Where there is a problem, UNICOM
operators are encouraged to develop a "least
interference" frequency assignment plan for airports
concerned using the frequencies designated for
airports without operating control towers. UNICOM
licensees are encouraged to apply for UNICOM 25 kHz
spaced channel frequencies. Due to the extremely
limited number of frequencies with 50 kHz channel
spacing, 25 kHz channel spacing should be
implemented. UNICOM licensees may then request FCC
to assign frequencies in accordance with the plan,
which FCC will review and consider for approval.
2.
Wind
direction and runway information may not be
available on UNICOM frequency 122.950.
2.
The following listing depicts other
frequency uses as designated by the Federal
Communications Commission (FCC). (See TBL 4-1-3.)
TBL 4-1-3
Other Frequency Usage
Designated by FCC
|
Use
|
Frequency
|
|
Air-to-air
communications & private airports (not open to the
public). |
122.750
122.850 |
|
Air-to-air
communications (general aviation helicopters).
|
123.025
|
|
Aviation
instruction, Glider, Hot Air Balloon (not to be
used for advisory service). |
123.300
123.500 |
4-1-12. Use of UNICOM for ATC
Purposes
UNICOM service may be
used for ATC purposes, only under the following
circumstances:
1.
Revision to proposed departure time.
2.
Takeoff, arrival, or flight plan
cancellation time.
3.
ATC clearance, provided arrangements
are made between the ATC facility and the UNICOM
licensee to handle such messages.

4-1-13.
Automatic Terminal Information Service (ATIS)
a.
ATIS is the continuous broadcast of
recorded noncontrol information in selected high
activity terminal areas. Its purpose is to improve
controller effectiveness and to relieve frequency
congestion by automating the repetitive transmission
of essential but routine information. The information
is continuously broadcast over a discrete VHF radio
frequency or the voice portion of a local NAVAID. ATIS
transmissions on a discrete VHF radio frequency are
engineered to be receivable to a maximum of 60 NM from
the ATIS site and a maximum altitude of 25,000 feet
AGL. At most locations, ATIS signals may be received
on the surface of the airport, but local conditions
may limit the maximum ATIS reception distance and/or
altitude. Pilots are urged to cooperate in the ATIS
program as it relieves frequency congestion on
approach control, ground control, and local control
frequencies. The A/FD indicates airports for which
ATIS is provided.
b.
ATIS information includes the time of
the latest weather sequence, ceiling, visibility,
obstructions to visibility, temperature, dew point (if
available), wind direction (magnetic), and velocity,
altimeter, other pertinent remarks, instrument
approach and runway in use. The ceiling/sky condition,
visibility, and obstructions to vision may be omitted
from the ATIS broadcast if the ceiling is above 5,000
feet and the visibility is more than 5 miles. The
departure runway will only be given if different from
the landing runway except at locations having a
separate ATIS for departure. The broadcast may include
the appropriate frequency and instructions for VFR
arrivals to make initial contact with approach
control. Pilots of aircraft arriving or departing the
terminal area can receive the continuous ATIS
broadcast at times when cockpit duties are least
pressing and listen to as many repeats as desired.
ATIS broadcast shall be updated upon the receipt of
any official hourly and special weather. A new
recording will also be made when there is a change in
other pertinent data such as runway change, instrument
approach in use, etc.
EXAMPLE-
Dulles International information Sierra. 1300 zulu
weather. Measured ceiling three thousand overcast.
Visibility three, smoke. Temperature six eight. Wind
three five zero at eight. Altimeter two niner niner
two. ILS runway one right approach in use. Landing
runway one right and left. Departure runway three
zero. Armel VORTAC out of service. Advise you have
Sierra.
c.
Pilots should listen to ATIS broadcasts
whenever ATIS is in operation.
d.
Pilots should notify controllers on
initial contact that they have received the ATIS
broadcast by repeating the alphabetical code word
appended to the broadcast.
EXAMPLE-
"Information Sierra received."
e.
When a pilot acknowledges receipt of
the ATIS broadcast, controllers may omit those items
contained in the broadcast if they are current.
Rapidly changing conditions will be issued by ATC and
the ATIS will contain words as follows:
EXAMPLE-
"Latest ceiling/visibility/altimeter/wind/(other
conditions) will be issued by approach control/tower."
NOTE-
The absence of a sky condition or ceiling and/or
visibility on ATIS indicates a sky condition or
ceiling of 5,000 feet or above and visibility of 5
miles or more. A remark may be made on the broadcast,
"the weather is better than 5000 and 5," or the
existing weather may be broadcast.
f.
Controllers will issue pertinent
information to pilots who do not acknowledge receipt
of a broadcast or who acknowledge receipt of a
broadcast which is not current.
g.
To serve frequency limited aircraft,
FSS's are equipped to transmit on the omnirange
frequency at most en route VOR's used as ATIS voice
outlets. Such communication interrupts the ATIS
broadcast. Pilots of aircraft equipped to receive on
other FSS frequencies are encouraged to do so in order
that these override transmissions may be kept to an
absolute minimum.
h.
While it is a good operating practice
for pilots to make use of the ATIS broadcast where it
is available, some pilots use the phrase "have
numbers" in communications with the control tower. Use
of this phrase means that the pilot has received wind,
runway, and altimeter information ONLY and the tower
does not have to repeat this information. It does not
indicate receipt of the ATIS broadcast and should
never be used for this purpose.

4-1-14. Radar
Traffic Information Service
This is a service
provided by radar ATC facilities. Pilots receiving this
service are advised of any radar target observed on the
radar display which may be in such proximity to the
position of their aircraft or its intended route of
flight that it warrants their attention. This service is
not intended to relieve the pilot of the responsibility
for continual vigilance to see and avoid other aircraft.
a. Purpose of the
Service
1.
The issuance of traffic information
as observed on a radar display is based on the
principle of assisting and advising a pilot that a
particular radar target's position and track
indicates it may intersect or pass in such proximity
to that pilot's intended flight path that it
warrants attention. This is to alert the pilot to
the traffic, to be on the lookout for it, and
thereby be in a better position to take appropriate
action should the need arise.
2.
Pilots are reminded that the
surveillance radar used by ATC does not provide
altitude information unless the aircraft is equipped
with Mode C and the radar facility is capable of
displaying altitude information.
b. Provisions of the
Service
1.
Many factors, such as limitations of
the radar, volume of traffic, controller workload
and communications frequency congestion, could
prevent the controller from providing this service.
Controllers possess complete discretion for
determining whether they are able to provide or
continue to provide this service in a specific case.
The controller's reason against providing or
continuing to provide the service in a particular
case is not subject to question nor need it be
communicated to the pilot. In other words, the
provision of this service is entirely dependent upon
whether controllers believe they are in a position
to provide it. Traffic information is routinely
provided to all aircraft operating on IFR flight
plans except when the pilot declines the service, or
the pilot is operating within Class A airspace.
Traffic information may be provided to flights not
operating on IFR flight plans when requested by
pilots of such flights.
NOTE-
Radar ATC facilities normally display and monitor
both primary and secondary radar when it is
available, except that secondary radar may be used
as the sole display source in Class A airspace, and
under some circumstances outside of Class A airspace
(beyond primary coverage and in en route areas where
only secondary is available). Secondary radar may
also be used outside Class A airspace as the sole
display source when the primary radar is temporarily
unusable or out of service. Pilots in contact with
the affected ATC facility are normally advised when
a temporary outage occurs; i.e., "primary radar out
of service; traffic advisories available on
transponder aircraft only." This means simply that
only the aircraft which have transponders installed
and in use will be depicted on ATC radar indicators
when the primary radar is temporarily out of
service.
2.
When receiving VFR radar advisory
service, pilots should monitor the assigned
frequency at all times. This is to preclude
controllers' concern for radio failure or emergency
assistance to aircraft under the controller's
jurisdiction. VFR radar advisory service does not
include vectors away from conflicting traffic unless
requested by the pilot. When advisory service is no
longer desired, advise the controller before
changing frequencies and then change your
transponder code to 1200, if applicable. Pilots
should also inform the controller when changing VFR
cruising altitude. Except in programs where radar
service is automatically terminated, the controller
will advise the aircraft when radar is terminated.
NOTE-
Participation by VFR pilots in formal programs
implemented at certain terminal locations
constitutes pilot request. This also applies to
participating pilots at those locations where
arriving VFR flights are encouraged to make their
first contact with the tower on the approach control
frequency.
c. Issuance of
Traffic Information.
Traffic
information will include the following concerning a
target which may constitute traffic for an aircraft
that is:
1. Radar
identified
(a)
Azimuth from the aircraft in terms
of the 12 hour clock, or
(b)
When rapidly maneuvering civil test
or military aircraft prevent accurate issuance of
traffic as in (a) above, specify the direction
from an aircraft's position in terms of the eight
cardinal compass points (N, NE, E, SE, S, SW, W,
NW). This method shall be terminated at the
pilot's request.
(c)
Distance from the aircraft in
nautical miles;
(d)
Direction in which the target is
proceeding; and
(e)
Type of aircraft and altitude if
known.
EXAMPLE-
Traffic 10 o'clock, 3 miles, west-bound (type
aircraft and altitude, if known, of the observed
traffic). The altitude may be known, by means of
Mode C, but not verified with the pilot for
accuracy. (To be valid for separation purposes by
ATC, the accuracy of Mode C readouts must be
verified. This is usually accomplished upon
initial entry into the radar system by a
comparison of the readout to pilot stated
altitude, or the field elevation in the case of
continuous readout being received from an aircraft
on the airport.) When necessary to issue traffic
advisories containing unverified altitude
information, the controller will issue the
advisory in the same manner as if it were verified
due to the accuracy of these readouts. The pilot
may upon receipt of traffic information, request a
vector (heading) to avoid such traffic. The vector
will be provided to the extent possible as
determined by the controller provided the aircraft
to be vectored is within the airspace under the
jurisdiction of the controller.
2. Not radar
identified
(a)
Distance and direction with respect
to a fix;
(b)
Direction in which the target is
proceeding; and
(c)
Type of aircraft and altitude if
known.
EXAMPLE-
Traffic 8 miles south of the airport
northeastbound, (type aircraft and altitude if
known).
d.
The examples depicted in the following
figures point out the possible error in the position
of this traffic when it is necessary for a pilot to
apply drift correction to maintain this track. This
error could also occur in the event a change in course
is made at the time radar traffic information is
issued.
FIG 4-1-1
Induced Error in
Position of Traffic
EXAMPLE-
In FIG 4-1-1 traffic information would be issued to
the pilot of aircraft "A" as 12 o'clock. The actual
position of the traffic as seen by the pilot of
aircraft "A" would be 2 o'clock. Traffic information
issued to aircraft "B" would also be given as 12
o'clock, but in this case, the pilot of "B" would see
the traffic at 10 o'clock.
FIG 4-1-2
Induced Error in
Position of Traffic
EXAMPLE-
In FIG 4-1-2 traffic information would be issued to
the pilot of aircraft "C" as 2 o'clock. The actual
position of the traffic as seen by the pilot of
aircraft "C" would be 3 o'clock. Traffic information
issued to aircraft "D" would be at an 11 o'clock
position. Since it is not necessary for the pilot of
aircraft "D" to apply wind correction (crab) to remain
on track, the actual position of the traffic issued
would be correct. Since the radar controller can only
observe aircraft track (course) on the radar display,
traffic advisories are issued accordingly, and pilots
should give due consideration to this fact when
looking for reported traffic.

4-1-15. Safety Alert
A safety alert will be
issued to pilots of aircraft being controlled by ATC if
the controller is aware the aircraft is at an altitude
which, in the controller's judgment, places the aircraft
in unsafe proximity to terrain, obstructions or other
aircraft. The provision of this service is contingent
upon the capability of the controller to have an
awareness of a situation involving unsafe proximity to
terrain, obstructions and uncontrolled aircraft. The
issuance of a safety alert cannot be mandated, but it
can be expected on a reasonable, though intermittent
basis. Once the alert is issued, it is solely the
pilot's prerogative to determine what course of action,
if any, to take. This procedure is intended for use in
time critical situations where aircraft safety is in
question. Noncritical situations should be handled via
the normal traffic alert procedures.
a. Terrain or
Obstruction Alert
1.
Controllers will immediately issue an
alert to the pilot of an aircraft under their
control when they recognize that the aircraft is at
an altitude which, in their judgment, may be in an
unsafe proximity to terrain/obstructions. The
primary method of detecting unsafe proximity is
through Mode C automatic altitude reports.
EXAMPLE-
Low altitude alert, check your altitude immediately.
The, as appropriate, MEA/MVA/MOCA in your area is
(altitude) or, if past the final approach fix (nonprecision
approach) or the outer marker or fix used in lieu of
the outer marker (precision approach), the, as
appropriate, MDA/DH (if known) is (altitude).
2.
Terminal ARTS IIA, III, AND IIIA
facilities have an automated function which, if
operating, alerts controllers when a tracked Mode C
equipped aircraft under their control is below or is
predicted to be below a predetermined minimum safe
altitude. This function, called Minimum Safe
Altitude Warning (MSAW), is designed solely as a
controller aid in detecting potentially unsafe
aircraft proximity to terrain/obstructions. The ARTS
IIA, III, and IIIA facility will, when MSAW is
operating, provide MSAW monitoring for all aircraft
with an operating Mode C altitude encoding
transponder that are tracked by the system and are:
(a)
Operating on an IFR flight plan; or
(b)
Operating VFR and have requested
MSAW monitoring.
3.
Terminal AN/TPX-42A (number beacon
decoder system) facilities have an automated
function called Low Altitude Alert System (LAAS).
Although not as sophisticated as MSAW, LAAS alerts
the controller when a Mode C transponder equipped
aircraft operating on an IFR flight plan is below a
predetermined minimum safe altitude.
NOTE-
Pilots operating VFR may request MSAW or LAAS
monitoring if their aircraft are equipped with Mode
C transponders.
EXAMPLE-
Apache Three Three Papa request MSAW/LAAS.
b. Aircraft Conflict
Alert.
1.
Controllers will immediately issue an
alert to the pilot of an aircraft under their
control if they are aware of another aircraft which
is not under their control, at an altitude which, in
the controller's judgment, places both aircraft in
unsafe proximity to each other. With the alert, when
feasible, the controller will offer the pilot the
position of the traffic if time permits and an
alternate course(s) of action. Any alternate
course(s) of action the controller may recommend to
the pilot will be predicated only on other traffic
being worked by the controller.
EXAMPLE-
American Three, traffic alert, (position of traffic,
if time permits), advise you turn right/left heading
(degrees) and/or climb/descend to (altitude)
immediately.

4-1-16. Radar Assistance to
VFR Aircraft
a.
Radar equipped FAA ATC facilities
provide radar assistance and navigation service
(vectors) to VFR aircraft provided the aircraft can
communicate with the facility, are within radar
coverage, and can be radar identified.
b.
Pilots should clearly understand that
authorization to proceed in accordance with such radar
navigational assistance does not constitute
authorization for the pilot to violate CFR's. In
effect, assistance provided is on the basis that
navigational guidance information issued is advisory
in nature and the job of flying the aircraft safely,
remains with the pilot.
c.
In many cases, controllers will be
unable to determine if flight into instrument
conditions will result from their instructions. To
avoid possible hazards resulting from being vectored
into IFR conditions, pilots should keep controllers
advised of the weather conditions in which they are
operating and along the course ahead.
d.
Radar navigation assistance (vectors)
may be initiated by the controller when one of the
following conditions exist:
1.
The controller suggests the vector
and the pilot concurs.
2.
A special program has been
established and vectoring service has been
advertised.
3.
In the controller's judgment the
vector is necessary for air safety.
e.
Radar navigation assistance (vectors)
and other radar derived information may be provided in
response to pilot requests. Many factors, such as
limitations of radar, volume of traffic,
communications frequency, congestion, and controller
workload could prevent the controller from providing
it. Controllers have complete discretion for
determining if they are able to provide the service in
a particular case. Their decision not to provide the
service in a particular case is not subject to
question.

4-1-17.
Terminal Radar Services for VFR Aircraft
a. Basic Radar
Service:
1.
In addition to the use of radar for
the control of IFR aircraft, all commissioned radar
facilities provide the following basic radar
services for VFR aircraft:
(a)
Safety alerts.
(b)
Traffic advisories.
(c)
Limited radar vectoring (on a
workload permitting basis).
(d)
Sequencing at locations where
procedures have been established for this purpose
and/or when covered by a Letter of Agreement.
NOTE-
When the stage services were developed, two basic
radar services (traffic advisories and limited
vectoring) were identified as "Stage I." This
definition became unnecessary and the term "Stage
I" was eliminated from use. The term "Stage II"
has been eliminated in conjunction with the
airspace reclassification, and sequencing services
to locations with local procedures and/or letters
of agreement to provide this service have been
included in basic services to VFR aircraft. These
basic services will still be provided by all
terminal radar facilities whether they include
Class B, Class C, Class D or Class E airspace.
"Stage III" services have been replaced with
"Class B" and "TRSA" service where applicable.
2.
Vectoring service may be provided
when requested by the pilot or with pilot
concurrence when suggested by ATC.
3.
Pilots of arriving aircraft should
contact approach control on the publicized frequency
and give their position, altitude, aircraft call
sign, type aircraft, radar beacon code (if
transponder equipped), destination, and request
traffic information.
4.
Approach control will issue wind and
runway, except when the pilot states "have numbers"
or this information is contained in the ATIS
broadcast and the pilot states that the current ATIS
information has been receiv |