There is a lot of debate around how to enter the traffic pattern at a non-towered field. A lot of experienced pilots make very good arguments for alternate ways of entering the pattern.
However, I am going to simplify this for you and recommend the most standard way to enter the pattern. It is in line with the FAA’s recommendations and safe to fly at non-towered fields.
To enter the pattern fly to a point that is at least 5 miles out and 45 degrees from the middle of the runway (see diagram below). Then turn inbound “on the 45” towards the middle of the runway.
When approaching the starting point of the 45 plan your altitude carefully. If you will be overflying within a few miles of the airport you should be at least 500 feet above the highest pattern altitude (look in the airport facilities directory).
No matter which way you are coming from be sure to announce your arrival and intentions when you are 10 miles from the airport. So if you are coming from the relative direction of travel on the 45 (top-right in the diagram) then you might announce “Chester County traffic, Cessna 12345 10 miles out on the 45 runway 11, Chester County”. However, if you will be crossing over the airport you should announce something like “Chester County traffic, Cessna 12345 10 miles south of the airport. We will cross over the field at 2500 and join the 45 runway 11, Chester County”.
Getting onto the 45
Once you reach the point where you want to join the 45 you need to carefully consider a plan that will allow you to end up at the correct altitude inbound on the 45 and clear of other traffic. If you are expecting to turn to the opposite direction to join the 45 it is good to plan early and fly a relatively wide turn. This will usually be needed when you overflew the airport. Don’t aim straight for the point where you plan to enter the 45. Instead, aim for a point that is a mile or 2 to the side so you will have some room to turn inbound.
Flying the 45
Flying the 45 is easy. Just stay at pattern altitude and fly towards the middle of the runway. Use this time primarily to look for traffic in the pattern and get ready to enter downwind. If you haven’t completed your pre-landing checklist yet this is a great time to do it.
Enter downwind at a point close enough to the airport that you could land if the engine failed. Don’t be tempted to turn too early and fly a wide dangerous downwind leg.
That’s it! You’ve entered the pattern.