An airfield traffic pattern (Close Pattern, Rectangular Pattern ) is a standard path followed by aircraft when taking off or landing while maintaining visual contact with the airfield. At an airport, the pattern (or circuit in the Commonwealth) is a standard path for coordinating air traffic.
When I was a student in the army aviation school in 1992, I learned the golden rule of standard traffic pattern entries: Always enter the downwind leg on a 45-degree angle and at pattern altitude. This is the best and safest entry, because it enables you to see other pilots in the pattern and enables those in the pattern to see you. It also allows you to establish yourself about a half-mile from the runway on a downwind ground track, which puts you in a familiar position from which to complete the pattern and your landing.
Everyone agrees that this is the way to do it, the question is how? How do you safely position yourself to make that 45-degree entry to the downwind leg at a non towered airport, take the wind and terrain (airport advisories are not always available and you can only discern so much from a sectional) into account, and get a good look at an unfamiliar airport? Just use your heading indicator (HI), which some pilots call the directional gyro (DG), and think in three dimensions.
Another way is to pass over the runway at the altitude of 1500 feet to be familiar with the entrance, wind, active runway etc.
Five basic steps
Fly to a position that gives you a good look at the airport and the windsock. Since both are best seen from above, fly directly over the airport. To safely stay out of the pattern, fly over the airport at an altitude that is at least 1,000 feet above traffic pattern altitude (not field elevation). Since most traffic patterns are between 800 and 1,000 feet above ground level (agl) don’t forget that faster, heavier, or turbine aircraft typically fly the traffic pattern at 1,500 AGL this should put you around 2,000 feet ACL or above. Your safety is assured by vertical rather than lateral separation. Remember, think in three dimensions.
While flying over the airport, look at the windsock, determine the wind direction, and select a runway on which to land that corresponds closest with the wind. Because runway numbers correspond to their magnetic directions, you will soon use your HI to set yourself up on a proper entry heading. While overhead, also look for aircraft in the pattern and on the ground ready to launch. (Don’t forget to monitor and use the common traffic advisory frequency, or CTAF.)
As you pass over the airport, look at your heading indicator. For a left-turning pattern, turn in the shortest direction that will place the selected runway’s heading on the first 45-degree tick to the right of the lubber line. This sets you on a course away from the airport directly opposite from the heading on which you will enter the pattern.
Fly this outbound heading until you reach the outside limit of what you would consider to be a normal pattern. Begin a normal descent upon reaching this point; 500 feet per minute (fpm) works well. Maintain your heading away from the airport until you have descended 500 feet (1 minute).
Look at the tick mark at the bottom of your heading indicator to find the reciprocal of your current heading. This is the course you will use to enter the downwind leg. While continuing your descent, turn 180 degrees to the right (into the wind) until this heading is under the lubber line. (Don’t forget to scan for traffic at all times.) Level off at pattern altitude. If you have done just right, you’ll be on a perfect 45-degree entry to the downwind.
The one important thing to remember with this procedure is to turn into the wind when reversing your course for the pattern entry. Turning with the wind will bring you into the downwind leg closer to the approach end of the runway than you might like. Limit your bank angles to 30 degrees or so. Especially in a high-wing airplane, any steeper bank angle will cause the wing to block your view while turning. Remember, you should be flying with your head up and swiveling, looking for traffic.