In addition to flying a basic rectangular traffic pattern, pilots operating at non tower controlled airports are urged to use the communications radio to announce their positions and intentions to a ground radio station located at those airports or, if none is functioning, to broadcast "in the blind" on an appropriate radio frequency. This alerts other pilots to the presence of your airplane and helps in avoiding midair collisions.
FAA has over 180 Flight Service Stations (FSS) which provide, on a designated radio frequency, advisory information concerning the airport at which they are located. These advisories, when requested, will include the speed and direction of the surface wind and other pertinent airport conditions - as well as the favored runway under the existing wind condition.
In addition, the FSS will advise the pilot if there is
observed or reported traffic in the traffic pattern, or in the vicinity,
so the pilot can approach or depart the airport in such manner as to avoid
disrupting or endangering other aircraft. These FSSs are listed, along
with their assigned frequency, in the Airport/Facility Directory published
by the U.S. Department of Commerce.
When there is no FAA facility on the airport, a radio service called UNICOM can be very useful to the pilot. The presence of a UNICOM facility at an airport is indicated in the Airport/Facility Directory and on sectional aeronautical charts; there are approximately 4,000 airports with UNICOM in the United States. This is an informal voluntary advisory service provided by the airport operator for the convenience of pilots. The UNICOM operator will relay information about known traffic in the area, and about the airport conditions.
UNICOM provides convenient air/ground communication, but it should be remembered that the person providing the information may or may not be an experienced observer of air traffic. It may be a veteran pilot, and again it may be someone who has no flying experience at all.
As standard operating practice, all traffic inbound to an uncontrolled airport should continuously monitor the appropriate radio frequency as indicated on the aeronautical chart or in the Airport/Facility Directory. To avoid radio interference with other air traffic that may be using UNICOM at nearby airports, the arriving pilot should delay the initial call until about 5 miles from the airport, and then listen before making any transmission.
Departing pilots should monitor the proper frequency, broadcasting their position and intentions before taxiing onto the runway for takeoff. To minimize congestion on the communication frequencies, all radio transmissions should be brief and concise as possible.
When two way radio communications are conducted, the pilot must have a Restricted Radiotelephone Operator Permit issued by the Federal Communications Commission, as required of everyone using a radio transmitter.