Standard Airport Traffic Patterns
A segmented circle in Figure 10-7 provides traffic patterns so there is no air traffic over the lower right hand area, which could be a hazard or populated area.
Inbound to an uncontrolled airport, the CTAF frequency should be monitored to listen for other aircraft in the pattern to find out what is the active runway being used by other air traffic. [Figure 10-8]
When approaching an airport for landing, the traffic pattern should be entered at a 45° angle to the downwind leg, headed toward a point abeam of the midpoint of the runway to be used for landing as shown in Figures 10-1 and 10-7.
Arriving aircraft should be at the proper traffic pattern altitude before entering the pattern and should stay 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. During the WSC 45° entry into the pattern, the WSC aircraft must pass through the larger airplane pattern, so it is essential that alert see-and-avoid procedures plus additional radio communications be practiced during this transition.
The entry leg should be of sufficient length to provide a clear view of the entire traffic pattern and to allow the pilot adequate time for planning the intended path in the pattern and the landing approach.
The downwind leg is a course flown parallel to the landing runway but in a direction opposite to the intended landing direction. This leg for the slower WSC aircraft should be approximately ¼ to ½ mile out from the landing runway, and at the specified traffic pattern altitude unless the airport specifically specifies a lower altitude for WSC aircraft. [Figure 10-9]
The faster airplanes would be ½ to 1 mile out from the landing runway. During this leg, the before landing check should be completed. Pattern altitude should be maintained until abeam the approach end of the landing runway. At this point, power should be reduced and a descent begun. The downwind leg continues past a point abeam the approach end of the runway to a point approximately 45° from the approach end of the runway, and a medium bank turn is made onto the base leg.
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, it is established 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 aircraft while on the base leg should be perpendicular to the extended centerline of the landing runway, although the longitudinal axis of the aircraft 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 and before turning onto the final approach, the pilot must ensure that there is no danger of colliding with another aircraft that may be on the final approach. This is especially important since the WSC aircraft is in a tighter pattern and could be flying onto the final approach of faster airplanes.
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 the pilot’s judgment and procedures must be the sharpest to control the airspeed and descent angle accurately while approaching the intended touchdown point.
As stipulated in 14 CFR part 91, aircraft while on final approach to land or while landing have the right-of-way over other aircraft in flight or operating on the surface. When two or more aircraft are approaching an airport for the purpose of landing, the aircraft at the lower altitude has the right of way. A pilot should not take advantage of this rule to cut in front of or overtake another aircraft on final approach.
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 aircraft leaves the ground and continues until the 90° turn onto the crosswind leg is started. 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 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.
An upwind leg is a course flown parallel to the landing runway, but in the same direction as the intended landing direction. The upwind leg continues past a point abeam the departure end of the runway to where a medium bank 90° turn is made onto the crosswind leg. The upwind leg is also the transitional part of the traffic pattern when on the final approach and a go-around is initiated and climb attitude is established. When a safe altitude is attained, the pilot should commence a shallow bank turn to the right side of the runway. This allows better visibility of the runway for departing aircraft. [Figure 10-10]
The crosswind leg is the part of the rectangular pattern that is horizontally perpendicular to the extended centerline of the takeoff runway and is entered by making approximately a 90° turn from the departure or upwind leg. On the crosswind leg, the aircraft proceeds to the downwind leg position.
In most cases, the takeoff is made into the wind in which case it is now approximately perpendicular to the aircraft’s flightpath. As a result, the aircraft has to be turned or headed slightly into the wind while on the crosswind leg to maintain a ground track that is perpendicular to the runway centerline extension.
Airport patterns provide organized air traffic flows into and out of an airport. An airport traffic pattern is established appropriate to the local conditions, including the direction and placement of the pattern, altitude to be fl own, and procedures for entering and leaving the pattern.
The legs of an airport pattern from takeoff are:
- Departure—direction of takeoff on the centerline of the runway
- Crosswind—first 90° turn flying perpendicular to the takeoff direction
- Downwind—second 90° turn flying parallel to the takeoff direction opposite the direction of takeoff and landing
- Base—third 90° turn flying perpendicular towards the runway centerline
- Final—forth 90° turn headed down the centerline of the runway to land
Pilots must research and determine from preflight preparation the possible runways and patterns for runways at the intended airports for the flight. The pilot must determine the actual pattern at the airport from observation and talking with other pilots on the CTAF or from the wind direction if no other pilots are in the pattern. Normal airport patterns are always left hand unless indicated otherwise.
Additional information on airport operations can be found in the Pilot’s Handbook of Aeronautical Knowledge, the Aeronautical Information Manual (AIM), Chapter 2, Aeronautical Lighting and Other Airport Visual Aids, Chapter 4, Air Traffic Control, and Chapter 5, Air Traffic Procedures; and 14 CFR part 91, Subpart B, Flight Rules, Subpart C, Equipment, Instrument and Certificate Requirements, and Subpart D, Special Flight Operations.