Several avionics manufacturers have announced plans to produce electronic flight instrument systems (EFIS) for general aviation aircraft. In recognition of the need for information concerning the impact of these new systems on pilot performance, the FAA has initiated a two-phased research program devoted to planning and conducting exploratory evaluations that will assess the ability of general aviation pilots to operate EFIS-equipped aircraft. The results of the first phase of this project are presented in this report. The objectives of this phase were to determine the specific goals of the exploratory evaluations and to develop general guidance--i.e., a conceptual approach--for their conduct. The conceptual approach is described in terms of (1) the information needed from the planned evaluations, (2) the general design of the overall study, (3) requirements for the performance measurement systems that would be employed to collect data and for the analysis of that data, (4) requirements for test facilities and equipment, and (5) procedures for selecting and training evaluation subjects. While the conceptual approach that was developed is specific to the planned research, it is discussed and described in general terms to increase its utility as general guidance for planning evaluations of pilot performance. (Author).