Pattern at a Non-Towered Airport
VFR operations at a non-towered airport is amongst one of the most challenging tasks to accomplish due to the numerous tasks at hand. Although a pilot is not required to transmit their intensions over the radio, it is highly recommended for added safety.
Many airports have a control tower that is responsible for separating inbound (landing) and outbound (departing) traffic in and out of the airport. A pilot must be aware of the airport's traffic pattern in order to facilitate airport operations.
When an airport does not have a control tower, pilots are responsible for their own traffic separation during takeoff, landing, taxi, and while in the airport's traffic pattern. Traffic separation is accomplished by transmitting their location and intensions over a common airport radio frequency known as the common traffic advisory frequency or CTAF.
The Traffic Pattern
Let us begin our understanding of operations at a non-towered airport with a few definitions.
Traffic Pattern - A standard path used by aircraft when landing, or taking off from an airport. Since the Cal Air training center is located at Knoxville Downtown Island Airport (KDKX) we will be using this airport in this tutorial.
Traffic Pattern Altitude - Unless otherwise stated, the traffic pattern for a small general aviation aircraft is 1,000 feet above ground level (AGL). The airport elevation at KDKX is 833 ft, therefore the traffic pattern altitude will be 1,833 ft.
Traffic Pattern direction of flight - Unless otherwise stated, the traffic pattern is a left pattern. A left traffic pattern means that you will be flying left turns around the traffic pattern. A right traffic pattern means that you will be flying right turns around the traffic pattern. At KDKX, the traffic pattern is a LEFT Pattern for both runway 8 and runway 26.
Traffic Pattern Legs - We will use a left traffic pattern in our example since the traffic pattern at KDKX is a left traffic pattern. We will be using runway 8 as our departure and arrival runway, and will assume zero wind conditions. The traffic pattern consists of the following legs:
Upwind (or departure) - You have just departed the airport, the upwind/departure leg is flown in the same heading as the runway you have departed. If the runway you have departed is runway 8, then your upwind/departure heading will be 080.
Crosswind - The crosswind leg is flown at at 90 degrees to the left from our departure heading. Our departure heading was 80 degrees, thus 90 degrees to the left of 80 degrees is a heading of 350 degrees. Our crosswind heading is at a heading of 350 degrees.
Downwind - The downwind leg is flown 90 degrees from our crosswind heading. Since our crosswind heading was 350 degrees, a 90 degrees turn to the left will of 350 degrees will produce a heading of 260 degrees. Our downwind heading will be a heading of 260. In other words, we are now heading in the opposite direction of our departure heading.
Base - The base leg is flown at 90 degrees of the downwind heading. Since our downwind heading was 260 degrees, a 90 degrees turn to the left of 260 will produce a new heading of 170 degrees. Our base leg heading is at a heading of 170 degrees.
Final - The final leg is flown at 90 degrees of the base leg heading. Since our base heading was 170 degrees, a 90 degrees turn to the left of 170 will produce a new heading of 80 degrees. Our final leg heading is at a heading of 80 degrees. (The same heading as the runway heading).
Arrivals and Departures at Non-Towered Airports
Arrivals - When arriving at a non-towered airport, one should first fly over the airport at mid-field at 500 ft above pattern altitude. As you fly over the airport, pay special attention to any traffic on the airport pattern. You then turn back towards the airport and enter the traffic pattern on the downwind leg at 45 degrees from the downwind heading. This is the 45 degrees entry point.
Departures - When departing a non-towered airport, departures should either be a straight-out departure, or at 45 degrees from the runway heading.
Radio Communications at Non-Towered Airports
As mentioned above, non-towered airports do not have a control tower, and all traffic separation depends on the aircraft pilot (VFR rules are see and avoid).
In order to aid in traffic separation, pilots coordinate with each other by communicating their intentions over the airports common traffic advisory frequency (CTAF). When communicating over the CTAF, a pilot must communicate as follows:
Name of the airport (plus the word traffic).
Let us use the following example. We are currently at the GA parking at KDKX. We will taxi to runway 8, takeoff runway 8, go around the pattern once, land and taxi back to the GA parking. NOTE: When announcing your location while in the pattern, always announce your position just prior to turning into the leg.
1. KDKX Traffic, NCX574 at GA parking, will taxi to runway 8.