Chapter 7: Airport Traffic Patterns
Airport traffic patterns are established to ensure that air traffic is flown into and out of an airport in a safe manner.
Each airport traffic pattern is developed 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.
Pilots must understand correct traffic pattern procedures. They also must 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).
Airport Traffic Patterns and Operations
Traffic patterns provide procedures for takeoffs, departures, arrivals, and landings.
Airports vary in complexity, from small grass or sod strips to major terminals with paved runways and taxiways.
At large airports, control towers and radar facilities provide a means of adjusting the flow of arriving and departing aircraft.
At smaller airports without a control tower, pilots announce their intentions on a Common Traffic Advisory Frequency (CTAF) and organize their own sequencing for pattern arrivals, landings, departures, and ground operations.
Whether a control tower is present or pilots organize the sequencing of aircraft, the objective of any traffic pattern is to keep air traffic moving with maximum safety and efficiency.
A single landing strip constitutes two runways. Each direction of landing is reciprocally offset (180°) from the other. Thus, an airport with one landing strip is said to have two runways, which are marked by two runway numbers. The runway in use, which determines the direction of departures and arrivals, is dependent upon wind conditions.
The calm-wind runway is the one designated for use when winds are below five (5) knots. When winds are either calm or light-and-variable, a control tower may use the reciprocal runways simultaneously for departures and arrivals. Pilots should exercise considerable vigilance when two reciprocal runways are active.
Runway numbers are aligned with the nearest two-digit magnetic heading. A runway with a magnetic heading of 184° would be "runway 18." A runway with a magnetic heading of 327° would be "runway 33." Because of the earth's slowly shifting magnetic field, an airport's runway numbers might change, particularly over a span of several years or decades.
Information on traffic patterns and operating procedures for an airport is documented in the Chart Supplement. In addition, the airport itself often has visual markings that can be seen from the air.
Standard Airport Traffic Patterns
An airport traffic pattern is established based on the local conditions. This includes the direction and altitude of the pattern. It also includes the procedures for entering and leaving the pattern.
In a traffic pattern, pilots should make all turns to the left. This is commonly referred to as a left-hand pattern, or simply left traffic. Left-hand patterns are preferred because the pilot's seat is on the left side of the airplane. Turns to the left provide the pilot with excellent visibility of the airport environment. Turns to the right offer the pilot less overall visibility.
Some airports will designate a right-hand pattern for specific runways, often because of terrain or noise abatement. In this case, the airport will display approved visual markings indicating that turns should be made to the right for a given runway. The Chart Supplement and aviation chart(s) also will indicate that a given runway uses right traffic.
Because right-hand patterns typically are designated so that aircraft do not overfly populated areas or high terrain, airports adjacent to these surrounding areas often will use left traffic for a given runway and right traffic for the reciprocal runway. This ensures that all aircraft traffic will remain on one side of the airport, regardless of which runway is in use. A non-towered airport with two-right hand patterns would be extremely rare (if one even exists).
The traffic pattern altitude (TPA) is usually 1,000 feet above the elevation of the airport surface, for piston aircraft. Large aircraft and jets operate at a traffic pattern altitude of 1,500 feet.
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. This is called the pattern-entry leg, although it's almost always called "the forty-five" by pilots. The pattern-entry leg is flown at traffic pattern altitude, and it should be of sufficient length to provide a clear view of the entire traffic pattern.
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 one-half (1/2) mile to one (1) mile from the landing runway and at the specified traffic pattern altitude. The pre-landing checklist is completed on this leg.
Pattern altitude is maintained on the downwind leg until at least abeam the approach end of the landing runway. At this point, the pilot should reduce power and begin a descent.
The downwind leg should be flown to a point approximately 45° from the approach end of the runway. Once this location is reached (typically 800 feet AGL, which is 200 feet below pattern altitude), the pilot should make a medium-bank turn toward the runway.
The base leg is flown with a ground track perpendicular to the runway. It should be flown at a sufficient distance from the approach end of the landing runway to permit a gradual descent on final approach to the intended touchdown point.
Since airplanes are always landed into the wind, if notable wind is present, the pilot may need to overshoot the aircraft heading on the base leg. The selected wind-correction angle should counter any drift created by a crosswind, keeping the ground-track of the base leg perpendicular to the runway.
While on the base leg, the pilot should look opposite the airport, opposite the direction of final approach, to ensure that there is no risk of colliding with an approaching aircraft already established on final approach.
The turn to the final approach leg should be a shallow-to-medium bank, even if the pilot overshoots the extended centerline. The bank angle should not exceed a medium bank, due to the risk of stalling while uncoordinated at a low airspeed and low altitude. An uncoordinated stall on the base-to-final turn likely would lead to a catastrophic accident.
Once established on the final approach leg, the pilot should fly a descending flightpath, starting from the completion of the base-to-final turn and extending to the point of touchdown.
If anything is in doubt on final approach, or if a safe landing is not assured, go around. The upwind leg is flown after go-arounds. This leg is parallel to the landing runway in the same direction as landing traffic.
Flying the upwind leg 1/2 mile to 1 mile from the airport (the same distance as the downwind leg) allows better visibility of the runway for departing aircraft.
On climb-out, many pilots will announce that they are "upwind," indicating that they are on the the upwind leg of the traffic pattern. While climb-out is flown into the wind, departing aircraft are on the departure leg, not the upwind leg.
The departure leg is flown with a ground-track along the runway's extended centerline, using a wind-correction angle if necessary.
Many departure legs lead to a straight-out departure, with no further participation in the traffic pattern. A 45° turn to the left or right from the departure leg (based on pattern direction) also can be used for pattern exit.
If the pilot intends to remain in the traffic pattern from the departure leg, the turn to the crosswind leg should be made at 700 feet AGL (300 feet below traffic pattern altitude). The crosswind leg is flown perpendicular to the runway, using any necessary wind-correction angle to maintain the ground track.
For aircraft remaining in the traffic pattern, climbing should terminate at traffic pattern altitude, regardless of if the aircraft is on the departure, crosswind, or downwind leg. Climb performance is affected by density altitude. A single aircraft can have various climb characteristics in various conditions.
When turning to the crosswind leg, the pilot may need to apply a wind-correction angle to counteract drift. In this case, the pilot can expect to undershoot the aircraft heading in order to maintain the proper ground track.
The crosswind leg should be flown until the pilot can make a make a 90° turn to the downwind leg, arriving wings-level on the downwind leg one-half (1/2) mile to one (1) mile from the runway. (In no-wind conditions, time on the crosswind leg is roughly 10 seconds.)
When turning to the downwind leg, pilots should scan the pattern-entry leg ("the forty-five") for inbound traffic.
At a non-towered airport — an airport without an operating 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.
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.
When operating in the traffic pattern at an airport without an operating control tower, the pilot should maintain an airspeed of no more than 200 knots, per regulations. However, this is a maximum figure. The pilot should adjust airspeed so that it is compatible with that of other airplanes in the pattern.
Traffic Pattern Indicators
Many airports have L-shaped traffic pattern indicators displayed with a segmented circle adjacent to the runway.
The marking at 90° to the runway illustrates from which direction the base leg is to be flown. The longer mark, which connects to the segmented circle, is parallel to the runway.
Typically, a windsock or other wind indicator will be located within the segmented circle to identify which runway is favorable for landing.
Pilots who are unsure of the favorable runway and traffic pattern direction should overfly the field at 500 feet above the highest traffic pattern to view the windsock and traffic pattern indicator before attempting a pattern entry. The midfield crossing normally will be 1,500 feet AGL, but it should be 2,000 feet AGL at any airport where large aircraft or jets are present.
Pattern Entry from the Upwind Leg Side of the Airport
For aircraft arriving at a non-towered airport from the upwind leg side, there are two additional methods to enter the pattern.
One method of entry from the opposite side of the pattern is to announce your intentions and cross midfield at least 500 feet above the highest traffic pattern altitude (1,500 or 2,000 feet AGL).
The crossing altitude should be maintained until clear of the traffic pattern, typically about two (2) miles from the runway. The pilot should then make a descending teardrop turn to the pattern entry leg, and then establish on the pattern entry leg at traffic pattern altitude.
An alternate method for pattern entry from the upwind side of the airport is the midfield crosswind, which is done at pattern altitude. Due to the risk of collision, this technique should not be used if the pattern is busy.
For the midfield crosswind entry, the pilot crosses the airport at midfield — carefully scanning for traffic while announce intentions — and then turns to join the downwind leg. Traffic on a midfield crosswind entry must yield to any arriving traffic on the forty-five, which is the preferred entry leg.
When operating at an airport with an operating control tower, the pilot receives an ATC clearance to approach or depart, as well as pertinent information about the traffic pattern.
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.
While left-hand patterns are typically preferred at both towered and non-towered airports, ATC can assign left traffic or right traffic to any active runway, provided the traffic pattern conforms to terrain and noise-abatement requirements. Multiple airplanes may be sequenced to an active runway using both right-hand and left-hand traffic.
Jets or heavy airplanes will frequently fly wider and/or higher patterns than lighter airplanes. In many cases, ATC will assign large aircraft a straight-in approach for landing. ATC may instruct slower airplanes to modify their patterns in order to accomodate these approaches.
According to the National Transportation Safety Board (NTSB), the most probable cause of mid-air collisions is the pilot failing to see and avoid other aircraft.
Midair collisions usually occur on clear days with unlimited visibility. Never assume you have found all of the air traffic and stop scanning.
High-wing airplanes have restricted visibility above while low-wing airplanes have limited visibility below. The worst-case scenario is a low- wing airplane flying above a high-wing airplane.
Important facts about midair collisions include:
Critical procedures and tasks that all pilots should be follow when flying in a traffic pattern or in the vicinity of an airport include:
Commercial Pilot & Flight Instructor Test Questions
A turbine-powered or large airplane is required to enter an airport traffic pattern at an altitude of at least 1,500 feet. (91.129)
What is an effective way to prevent a collision hazard in the traffic pattern? Maintain the proper traffic pattern altitude and continually scan the area.