This report discusses the operational performance of the FAA ATCRBS system, as determined from data extracted from the ARTS III digital processing system. Data was gathered from several sites including Andrews Air Force Base, (Md.), Logan International Airport (Boston, Mass.), and McCarran International Airport (Las Vegas, Nevada). Quantitative performance data, as well as discussion of the problem area and possible techniques and procedures for its solution, are provided in the areas of weak/broken targets, false targets, synchronous garble, interference, erroneous decoding, improper defruiter operation, and insufficient angular resolution. A discussion of improvements that can alleviate some of the deficiences of today's secondary radar (ATCRBS) system is included.