Traffic Pattern procedures develop the ability to stay safely
and efficiently arrive at an uncontrolled airport, or after arrival,
utilize the traffic pattern
The traffic pattern is comprised of several components which standardized flow of aircraft, at a specific altitude within the terminal area
This standard flow allows for predictability in an otherwise extremely dangerous environment
The traffic pattern is the ultimate goal which began with the rectangular course with many hazards
Traffic Pattern Components:
The traffic pattern is divided into legs which form a rectangle
Legs define a phase of flight associated with takeoff, landing, or closed pattern touch and go operations
The following terminology for the various components of a
traffic pattern has been adopted as standard for use by control towers
and pilots [Figure 1/2]
Diagrams are intended only to illustrate terminology used
in identifying various components of a traffic pattern. It should not be
used as a reference or guide on how to enter a traffic pattern
Arrival:
Pilots are encouraged to use the standard traffic
pattern. However, those pilots who choose to execute a straight-in
approach, maneuvering for and execution of the approach should not
disrupt the flow of arriving and departing traffic. Likewise, pilots
operating in the traffic pattern should be alert at all times for
aircraft executing straight-in approaches
*RP indicates special conditions exist and refers pilots to the Chart Supplement U.S
Right traffic patterns are not shown at airports with full-time control towers
Upwind Leg:
A flight path parallel to the landing runway in the landing direction
Note, the upwind leg is separate and distinct from the
departure leg and often used to reference the flight path flown after
takeoff (or a touch and go)
Crosswind Leg:
A flight path at right angles to the landing runway off its takeoff end
The direction of the crosswind leg (left or right turn) is dictated by the airport publications or tower
Downwind Leg:
A flight path parallel to the landing runway in the opposite direction of landing
While it is the longest leg, it requires the most vigilance for traffic entering and departing
Base Leg:
A flight path at right angles to the landing runway off
its approach end and extending from the downwind leg to the intersection
of the extended runway centerline
Final Approach:
A flight path in the direction of landing along the extended runway centerline from the base leg to the runway
Before touching down, check for waive-off lights if present, or light signals from tower
Departure:
The flight path which begins after takeoff and continues straight ahead along the extended runway centerline
The departure climb continues until reaching a point at
least 1/2 mile beyond the departure end of the runway and within 300
feet of the traffic pattern altitude
May exit 45° off in the direction of the pattern turns as well
Traffic Pattern Altitude:
Traffic pattern altitudes (discussed below) should be
maintained unless another traffic pattern altitude is published in the
Chart Supplement U.S. or unless otherwise required
Propeller-driven aircraft enter the traffic pattern at 1,000 feet above ground level (AGL)
Large and turbine-powered aircraft enter the traffic
pattern at an altitude of not less than 1,500 feet AGL or 500 feet above
the established pattern altitude
Helicopters operating in the traffic pattern may fly a
pattern similar to the fixed-wing aircraft pattern, but at a lower
altitude (500 AGL) and closer to the runway. This pattern may be on the
opposite side of the runway from fixed-wing traffic when airspeed
requires or for practice power-off landings (autorotation) and if local
policy permits. Landings not to the runway must avoid the flow of fixed
wing traffic
A pilot may vary the size of the traffic pattern depending on
the aircraft's performance characteristics. Pilots of en route aircraft
should be constantly alert for aircraft in traffic patterns and avoid
these areas whenever possible
Except when conducting a circling approach or unless otherwise required by ATC, each pilot must:
Circle the airport to the left if operating an airplane; or
Avoid the flow of fixed-wing aircraft, if operating a helicopter
On Sectional, Aeronautical, and VFR Terminal Area Charts,
right traffic patterns are indicated at public-use and joint-use
airports with the abbreviation "RP" (for Right Pattern), followed by the
appropriate runway number(s) at the bottom of the airport data block
EXAMPLE: RP 9, 18, 22R
RP* indicates special conditions exist and refers pilots to the Chart Supplement U.S.
Right traffic patterns are not shown at airports with full-time control towers
Unless otherwise required by the applicable distance from clouds (FAR 91.155) or operations, pilots should maintain traffic pattern altitude
Traffic patterns are left turns by standard, unless ATC or the Chart Supplement U.S. states otherwise, as shown in Meadows Field below, under RWY 30R and 12R with the text "Rgt tfc"
Wind conditions affect all airplanes in varying degrees.
Figure 4-3-4 is an example of a chart used to determine the headwind,
crosswind, and tailwind components based on wind direction and velocity
relative to the runway. Pilots should refer to similar information
provided by the aircraft manufacturer when determining these wind
components
Keys to Traffic Pattern Operations:
Enter pattern in level flight, abeam midpoint of the runway,
at pattern altitude (1,000' AGL is recommended pattern altitude unless
established otherwise...)
Try not to enter the pattern on base/final even if that is
the quickest as it does not afford you a look at the runway until you're
on final
Maintain pattern altitude until abeam approach end of the landing runway on downwind leg
Complete turn to final at least 1/4 mile from the runway
Continue straight ahead until beyond departure end of runway
If remaining in the traffic pattern, commence turn to
crosswind leg beyond the departure end of the runway within 300' of
pattern altitude
If departing the traffic pattern, continue straight out, or
exit with a 45° turn (to the left when in a left-hand traffic pattern;
to the right when in a right-hand traffic pattern) beyond the departure
end of the runway, after reaching pattern altitude
Maintain situational awareness to anyone entering the
traffic pattern on a 45° angle as they may be flying directly toward or
paralleling the departure track
Do not overshoot final or continue on a track, which will penetrate the final approach of the parallel runway
Do not continue on a track, which will penetrate the departure path of a parallel runway
Maintain approximately 1/2 a mile distance from the runway when on downwind
Distance from the airport can be referenced by landmarks or using runway lengths for perspective
Towered Airports:
When operating at an airport where traffic control is
exercised by a tower, two-way communication is required, unless
otherwise authorized
Initial callup should be made about 15 miles from the airport
Unless there is a good reason to leave the tower frequency
before exiting the Class B, Class C, and Class D surface areas, it is a
good operating practice to remain on the tower frequency for the purpose
of receiving traffic information
It is not necessary to request permission to leave the
tower frequency once outside of Class B, Class C, and Class D surface
areas, as it reduces frequency congestion
When operating at uncontrolled fields, keep to normal towered procedures to remain predictable
Not all airports with an operating control tower will have
Class D airspace and thus do not have weather reporting which is a
requirement for surface based controlled airspace, previously known as a
control zone
The controlled airspace over these airports will normally begin at 700' or 1,200' AGL (see Class Echo Airspace) and can be determined from the visual aeronautical charts
Pilots are expected to use good operating practices and communicate with the control tower, same as above
When necessary, the tower controller will issue clearances or
other information for aircraft to generally follow the desired flight
path (traffic patterns) when flying in Class B, Class C, and Class D
surface areas and the proper taxi routes when operating on the ground
Thus, if not otherwise authorized or directed by the tower,
pilots of fixed-wing aircraft approaching to land must circle the
airport to the left
Pilots approaching to land in a helicopter must avoid the flow of fixed-wing traffic
In all instances, an appropriate clearance must be received from the tower before landing
Many towers will have radar display which are intended to
enhance the effectiveness and efficiency of the local control, or tower,
position
They are not intended to provide radar services or benefits
to pilots except as they may accrue through a more efficient tower
operation
The four basic uses are:
Determining an Aircraft's Exact Location:
Accomplished by radar identifying the VFR aircraft
through any of the techniques available to a radar position, such as
having the aircraft squawk ident
Once identified, the aircraft's position and spatial
relationship to other aircraft can be quickly determined, and standard
instructions regarding VFR operation in Class B, Class C, and Class D
surface areas will be issued
Once initial radar identification of a VFR aircraft has
been established and the appropriate instructions have been issued,
radar monitoring may be discontinued; the reason being that the local
controller's primary means of surveillance in VFR conditions is visually
scanning the airport and local area
Provide Radar Traffic Advisories:
Radar traffic advisories may be provided to the extent that the local controller is able to monitor the radar display
Local control has primary control responsibilities to
the aircraft operating on the runways, which will normally supersede
radar monitoring duties
Provide Direction or Suggested Heading:
The local controller may provide pilots flying VFR with generalized instructions which will facilitate operations; e.g., "Proceed southwest-bound, enter a right downwind runway three zero," or provide a suggested heading to establish radar identification or as an advisory aid to navigation; "Suggested heading two two zero, for radar identification"
In both cases, the instructions are advisory aids to
the pilot flying VFR and are not radar vectors which gives pilots
complete discretion regarding acceptance of the suggestions as they have
sole responsibility for seeing and avoiding other aircraft
Provide Information and Instructions:
In an example of this situation, the local controller
would use the radar to advise a pilot on an extended downwind when to
turn base leg
NOTE: The above tower radar applications are intended
to augment the standard functions of the local control position. There
is no controller requirement to maintain constant radar identification.
In fact, such a requirement could compromise the local controller's
ability to visually scan the airport and local area to meet FAA
responsibilities to the aircraft operating on the runways and within the
Class B, Class C, and Class D surface areas. Normally, pilots will not
be advised of being in radar contact since that continued status cannot
be guaranteed and since the purpose of the radar identification is not
to establish a link for the provision of radar services
A few of the radar equipped towers are authorized to use the
radar to ensure separation between aircraft in specific situations,
while still others may function as limited radar approach controls
The various radar uses are strictly a function of FAA
operational need. The facilities may be indistinguishable to pilots
since they are all referred to as tower and no publication lists the
degree of radar use
Therefore, when in communication with a tower controller
who may have radar available, do not assume that constant radar
monitoring and complete ATC radar services are being provided
Non-towered Airports:
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; and
Pilots use the correct airport name, as identified in
appropriate aeronautical publications, to reduce the risk of confusion
when communicating their position, intentions, and/or exchanging traffic
information
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:
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 Chart Supplement U.S.
and approach charts
Airport Advisory/Information Services Provided by a FSS:
There are three advisory type services provided at selected airports
Local Airport Advisory (LAA) is available only in
Alaska and 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 - basis. The CTAF for LAA airports is disseminated in the
appropriate aeronautical publications
Remote Airport Information Service (RAIS) is provided
in support of special events at nontowered airports by request from the
airport authority
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
Inbound:
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
Outbound:
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
Airport advisory service includes wind direction and
velocity, favored or designated runway, altimeter setting, known
airborne and ground traffic, NOTAMs, 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
All aircraft in the vicinity of an airport may not be in communication with the FSS
Information Provided by Aeronautical Advisory Stations (UNICOM):
UNICOM is a non-government air/ground radio communication
station which may provide airport information at public use airports
where there is no tower or FSS
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 [Figure 2]
UNICOM Communications Procedures
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:
Select the correct UNICOM frequency
State the identification of the UNICOM station you are calling in each transmission
Speak slowly and distinctly
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
Report on downwind, base, and final approach
Report leaving the runway
Recommended UNICOM phraseologies:
Inbound:
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
Outbound:
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
Self-Announce Position and/or Intentions:
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. Pilots stating, "Traffic in the area, please advise" is
not a recognized Self-Announce Position and/or Intention phrase and
should not be used under any condition
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
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
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:
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);
Established on the final approach segment or immediately upon being released by ATC;
Upon completion or termination of the approach; and
Upon executing the missed approach procedure
Departing aircraft should always be alert for arrival aircraft coming from the opposite direction
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
Inbound:
"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"
Outbound:
"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"
Practice Instrument Approach:
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
Communicating on a Common Frequency:
The key to communicating at an airport without an
operating control tower is selection of the correct common traffic
advisory frequency, or CTAF. 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
FSS frequencies are available only in Alaska
In Alaska, a CTAF may also be designated for the purpose
of carrying out advisory practices while operating in designated areas
with a high volume of VFR traffic
The CTAF frequency for a particular airport or area is
contained in the Chart Supplement U.S., 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
Recommended Traffic Advisory Practices:
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 CFRs or local procedures require otherwise
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 CFRs or local procedures. Such operations include
parachute jumping/dropping, en route, practicing maneuvers, etc.
In Alaska, pilots of aircraft conducting other than
arriving or departing operations in designated CTAF areas should
monitor/communicate on the appropriate frequency while within the
designated area, unless required to do otherwise by CFRs or local
procedures. Such operations include parachute jumping/dropping, en route, practicing maneuvers, etc.
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
Traffic Pattern Arrival:
Procedure:
Complete the descent checklist
At least 10 NM from the airport, attempt to determine the active runway
If the runway in use cannot be determined:
Over fly the airport at 500-1,000' above traffic pattern
altitude to observe traffic, wind direction indications, etc. to
determine a runway to use
At least 2 NM from the runway, enter the traffic pattern at
traffic pattern altitude on a 45° entry to the downwind, maintaining a
none-half mile distance from the runway on the downwind leg
Complete the appropriate approach and landing procedure
Maintain pattern altitude until abeam approach end of the landing runway on the downwind leg
Complete turn to final at least 1/4 mile from the runway
Traffic Pattern Responsibilities:
Pilot Responsibilities:
Acknowledges receipt of traffic advisories
Informs controller if traffic in sight
Advises ATC if a vector to avoid traffic is desired
Does not expect to receive radar traffic advisories on
all traffic. Some aircraft may not appear on the radar display. Be aware
that the controller may be occupied with higher priority duties and
unable to issue traffic information for a variety of reasons
Advises controller if service is not desired
Controller Responsibilities:
Issues radar traffic to the maximum extent consistent with higher priority duties except in Class A airspace
Provides vectors to assist aircraft to avoid observed traffic when requested by the pilot
Issues traffic information to aircraft in the Class B, C, and D surface areas for sequencing purposes
Controllers are required to issue to each aircraft
operating on intersecting or non-intersecting converging runways where
projected flight paths will cross
Visual Indicators at Airports Without an Operating Control Tower:
At those airports without an operating control tower, a
segmented circle visual indicator system, if installed, (see AIM,
Paragraph 4-1-9, Traffic Advisory Practices at Airports Without
Operating Control Towers) is designed to provide traffic pattern
information
The segmented circle system consists of the following components:
Segmented Circle:
Located in a position affording maximum visibility to
pilots in the air and on the ground and providing a centralized location
for other elements of the system [Figure 7]
Wind Direction Indicators:
A wind cone, wind sock, or wind tee installed near the
operational runway to indicate wind direction. The large end of the wind
cone/wind sock points into the wind as does the large end (cross bar)
of the wind tee. In lieu of a tetrahedron and where a wind sock or wind
cone is collocated with a wind tee, the wind tee may be manually aligned
with the runway in use to indicate landing direction. These signaling
devices may be located in the center of the segmented circle and may be
lighted for night use. Pilots are cautioned against using a tetrahedron
to indicate wind direction [Figure 8]
In the case of conflicting wind socks, consider their
placement, obstacles that may cause interference, and which may have
proximity to the runway
Landing Direction Indicator:
A tetrahedron is installed when conditions at the
airport warrant its use. It may be used to indicate the direction of
landings and takeoffs. A tetrahedron may be located at the center of a
segmented circle and may be lighted for night operations. The small end
of the tetrahedron points in the direction of landing. Pilots are
cautioned against using a tetrahedron for any purpose other than as an
indicator of landing direction. Further, pilots should use extreme
caution when making runway selection by use of a tetrahedron in very
light or calm wind conditions as the tetrahedron may not be aligned with
the designated calm-wind runway. At airports with control towers, the
tetrahedron should only be referenced when the control tower is not in
operation. Tower instructions supersede tetrahedron indications
Landing Strip Indicators:
Installed in pairs as shown in the segmented circle diagram and used to show the alignment of landing strips
Traffic Pattern Indicators:
Arranged in pairs in conjunction with landing strip
indicators and used to indicate the direction of turns when there is a
variation from the normal left traffic pattern. (If there is no
segmented circle installed at the airport, traffic pattern indicators
may be installed on or near the end of the runway)
Preparatory to landing at an airport without a control tower,
or when the control tower is not in operation, pilots should concern
themselves with the indicator for the approach end of the runway to be
used. When approaching for landing, all turns must be made to the left
unless a traffic pattern indicator indicates that turns should be made
to the right. If the pilot will mentally enlarge the indicator for the
runway to be used, the base and final approach legs of the traffic
pattern to be flown immediately become apparent. Similar treatment of
the indicator at the departure end of the runway will clearly indicate
the direction of turn after takeoff
When two or more aircraft are approaching an airport for the
purpose of landing, the pilot of the aircraft at the lower altitude has
the right-of-way over the pilot of the aircraft at the higher altitude.
However, the pilot operating at the lower altitude should not take
advantage of another aircraft, which is on final approach to land, by
cutting in front of, or overtaking that aircraft
Unexpected Maneuvers in the Airport Traffic Pattern:
There have been several incidents in the vicinity of
controlled airports that were caused primarily by aircraft executing
unexpected maneuvers
Controllers establish the sequence of arriving and departing
aircraft by requiring them to adjust flight as necessary to achieve
proper spacing
These adjustments can only be based on observed traffic, accurate pilot reports, and anticipated aircraft maneuvers
Pilots are expected to cooperate so as to preclude disrupting traffic flows or creating conflicting patterns
The pilot-in-command of an aircraft is directly responsible for and is the final authority as to the operation of the aircraft
On occasion it may be necessary for pilots to maneuver their
aircraft to maintain spacing with the traffic they have been sequenced
to follow
The controller can anticipate minor maneuvering such as shallow "S" turns
The controller cannot, however, anticipate a major maneuver such as a 360° turn
If a pilot makes a 360° turn after obtaining a landing
sequence, the result is usually a gap in the landing interval and, more
importantly, it causes a chain reaction which may result in a conflict
with following traffic and an interruption of the sequence established
by the tower or approach controller
Should a pilot decide to make maneuvering turns to maintain
spacing behind a preceding aircraft, the pilot should always advise the
controller if at all possible
Except when requested by the controller or in emergency
situations, a 360° turn should never be executed in the traffic pattern
or when receiving radar service without first advising the controller
Conclusion:
The name says it all as the "pattern" is a predictable flow of traffic in a congested area
Remember that it is not required to have a radio (and
therefore make radio calls) prior to takeoff or landing at an
uncontrolled airfield