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Airport Traffic Patterns
- Introduction
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Airport traffic
patterns are developed to ensure that air traffic
is flown into and out of an airport safely.
Each airport traffic pattern is established
based on the local conditions, including the
direction and placement of the pattern, the
altitude at which it is to be flown, and the
procedures for entering and exiting the pattern.
It is imperative that pilots are taught correct
traffic pattern procedures and exercise constant
vigilance in the vicinity of airports when entering
and exiting the traffic pattern. Information
regarding the procedures for a specific airport
can be found in the Chart Supplements. Additional
information on airport operations and traffic
patterns can be found in the Aeronautical Information
Manual (AIM).
Traffic patterns provide procedures for takeoffs,
departures, arrivals, and landings. The exact
nature of each airport traffic pattern is dependent
on the runway in use, wind conditions (which
determine the runway in use), obstructions,
and other factors.
Control towers and radar facilities provide
a means of adjusting the flow of arriving and
departing aircraft and render assistance to
pilots in busy terminal areas.
Airport lighting and runway marking systems
are used frequently to alert pilots to abnormal
conditions and hazards so arrivals and departures
can be made safely.
Information on traffic patterns and operating
procedures for an airport is documented in the
Chart Supplements, as well as visual markings
on the airport itself. The use of any traffic
pattern, service, or procedure does not diminish
the pilot’s responsibility to see and avoid
other aircraft during flight.
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Airport Traffic
Patterns
- Standard Traffic Patterns
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To assure that
air traffic flows into and out of an airport
in an orderly manner, an airport traffic pattern
is established based on the local conditions,
to include the direction and altitude of the
pattern and the procedures for entering and
leaving the pattern. Unless the airport displays
approved visual markings indicating that turns
should be made to the right, the pilot should
make all turns in the pattern to the left.
When operating at an airport with an operating
control tower, the pilot receives a clearance
to approach or depart, as well as pertinent
information about the traffic pattern by radio.
If there is not a control tower, it is the pilot’s
responsibility to determine the direction of
the traffic pattern, to comply with the appropriate
traffic rules, and to display common courtesy
toward other pilots operating in the area.
A pilot is not expected to have extensive knowledge
of all traffic patterns at all airports, but
if the pilot is familiar with the basic rectangular
pattern, it is easy to make proper approaches
and departures from most airports, regardless
of whether or not they have control towers.
At airports with operating control towers, the
tower operator can instruct pilots to enter
the traffic pattern at any point or to make
a straight-in approach without flying the usual
rectangular pattern. Many other deviations are
possible if the tower operator and the pilot
work together in an effort to keep traffic moving
smoothly. Jets or heavy airplanes will frequently
fly wider and/or higher patterns than lighter
airplanes, and in many cases, will make a straight-in
approach for landing.
Compliance with the basic rectangular traffic
pattern reduces the possibility of conflicts
at airports without an operating control tower.
It is imperative that a pilot form the habit
of exercising constant vigilance in the vicinity
of airports even when the air traffic appears
to be light. Midair collisions usually occur
on clear days with unlimited visibility. Never
assume you have found all of the air traffic
and stop scanning.
When approaching an airport for landing, the
traffic pattern is normally entered at a 45°
angle to the downwind leg, headed toward a point
abeam the midpoint of the runway to be used
for landing. When arriving, the pilot should
be aware of the proper traffic pattern altitude
before entering the pattern and remain clear
of the traffic flow until established on the
entry leg. Entries into traffic patterns while
descending create specific collision hazards
and should always be avoided.
The pilot should ensure that the entry leg is
of sufficient length to provide a clear view
of the entire traffic pattern and to allow adequate
time for planning the intended path in the pattern
and the landing approach.
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DOWNWIND
The downwind leg is a course flown parallel
to the landing runway, but in a direction opposite
to the intended landing direction. This leg
is flown approximately 1.2 to 1 mile out from
the landing runway and at the specified traffic
pattern altitude. When flying on the downwind
leg, the pilot should complete all before landing
checks and extend the landing gear if the airplane
is equipped with retractable landing gear. Pattern
altitude is maintained until at least abeam
the approach end of the landing runway. At this
point, the pilot should reduce power and begin
a descent.
The pilot should continue the downwind leg past
a point abeam the approach end of the runway
to a point approximately 45‹ from
the approach end of the runway, and make a medium
bank turn onto the base leg. Pilots should consider
tailwinds and not descend too much on the downwind,
so as to have a very low base leg altitude.
BASE
The base leg is the transitional part of the
traffic pattern between the downwind leg and
the final approach leg. Depending on the wind
condition, the pilot should establish the base
leg at a sufficient distance from the approach
end of the landing runway to permit a gradual
descent to the intended touchdown point. The
ground track of the airplane while on the base
leg is perpendicular to the extended centerline
of the landing runway, although the longitudinal
axis of the airplane may not be aligned with
the ground track when it is necessary to turn
into the wind to counteract drift. While on
the base leg, the pilot must ensure, before
turning onto the final approach, that there
is no danger of colliding with another aircraft
that is already established on the final approach.
Pilots must not attempt an overly steep turn
to final, especially uncoordinated! If in doubt,
go around.
FINAL
The final approach leg is a descending flightpath
starting from the completion of the base-to-final
turn and extending to the point of touchdown.
This is probably the most important leg of the
entire pattern, because of the sound judgment
and precision required to accurately control
the airspeed and descent angle while approaching
the intended touchdown point.
UPWIND
The upwind leg is a course flown parallel to
the landing runway in the same direction as
landing traffic. The upwind leg is flown at
controlled airports and after go-arounds.
When necessary, the upwind leg is the part of
the traffic pattern in which the pilot will
transition from the final approach to the climb
altitude to initiate a go-around. When a safe
altitude is attained, the pilot should commence
a shallow bank turn to the upwind side of the
airport. This allows better visibility of the
runway for departing aircraft.
The departure leg of the rectangular pattern
is a straight course aligned with, and leading
from, the takeoff runway. This leg begins at
the point the airplane leaves the ground and
continues until the pilot begins the 90°
turn onto the crosswind leg.
On the departure leg after takeoff, the pilot
should continue climbing straight ahead and,
if remaining in the traffic pattern, commence
a turn to the crosswind leg beyond the departure
end of the runway within 300 feet of the traffic
pattern altitude. If departing the traffic pattern,
the pilot should 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 the traffic pattern
altitude.
CROSSWIND
The crosswind leg is the part of the rectangular
pattern that is horizontally perpendicular to
the extended centerline of the takeoff runway.
The pilot should enter the crosswind leg by
making approximately a 90° turn from the
upwind leg. The pilot should continue on the
crosswind leg, to the downwind leg position.
Since in most cases the takeoff is made into
the wind, the wind will now be approximately
perpendicular to the airplane’s flightpath.
As a result, the pilot should turn or head the
airplane slightly into the wind while on the
crosswind leg to maintain a ground track that
is perpendicular to the runway centerline extension.
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Airport Traffic
Patterns
- Non-Towered Airports
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When entering
the traffic pattern at an airport without an
operating control tower, inbound pilots are
expected to observe other aircraft already in
the pattern and to conform to the traffic pattern
in use.
If there are no other aircraft present, the
pilot should check traffic indicators on the
ground and wind indicators to determine which
runway and traffic pattern direction to use.
Many airports have L-shaped traffic pattern
indicators displayed with a segmented circle
adjacent to the runway. The short member of
the L shows the direction in which the traffic
pattern turns are made when using the runway
parallel to the long member. The pilot should
check the indicators from a distance or altitude
well away from any other airplanes that may
be flying in the traffic pattern. Upon identifying
the proper traffic pattern, the pilot should
enter into the traffic pattern at a point well
clear of the other airplanes.
Non towered airports traffic patterns are always
entered at pattern altitude. How you enter the
pattern depends upon the direction of arrival.
The preferred method for entering from the downwind
leg side of the pattern is to approach the pattern
on a course 45° to the downwind leg and
join the pattern at midfield.
There are several ways to enter the pattern
if you are coming from the upwind legs side
of the airport. One method of entry from the
opposite side of the pattern is to announce
your intentions and cross over midfield at least
500 feet above pattern altitude (normally 1,500
feet AGL.)
When well clear of the pattern—approximately
2 miles—scan carefully for traffic, descend
to pattern altitude, then turn right to enter
at 45° to the downwind leg at midfield.
[Figure 7-4A] An alternate method is to enter
on a midfield crosswind at pattern altitude,
carefully scan for traffic, announce your intentions
and then turned down downwind. [Figure 7-4B]
This technique should not be used if the pattern
is busy.
Always remember to give way to aircraft on the
preferred 45° entry and to aircraft already
established on downwind. In either case, it
is vital to announce your intentions, and remember
to scan outside. Before joining the downwind
leg, adjust your course or speed to blend into
the traffic. Adjust power on the downwind leg,
or sooner, to fit into the flow of traffic.
Avoid flying too fast or too slow. Speeds recommended
by the airplane manufacturer should be used.
They will generally fall between 70 to 80 knots
for fixed-gear singles, and 80 to 90 knots for
high-performance retractable.
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