The objective of this effort was to determine, by a relatively short experiment, the feasibility of utilizing user aircraft for the purpose of continuously monitoring the performance of primary radar systems. The experiment was designed to permit a technical and economic comparison between the user aircraft method of monitoring and the present periodic flight inspection analysis of the data collected indicated that it is both technically and economically feasible to perform radar flight inspection by utilizing user aircraft. It is estimated that approximately the same information presently being collected by periodic flight inspection could be collected with user aircraft for approximately one-fourth to one-third of the cost. Conversely, for the same cost as the present periodic flight in spection, approximately three to four times the information could be obtained by making use of the user aircraft technique. In addition, since the user data would be collected on a daily basis, degraded performance would be recognized earlier.