Increased emphasis has been placed on the need for and usefulness of major aviation training devices - flight simulators. A description of a modern trainer and the status of current simulation is provided. High fidelity is necessary to achieve high training transfer to the aircraft. The authors describe the need for and a proposed basic approach to technical simulator flight testing designed to achieve high fidelity. Ideas were formulated as a result of the authors' participation in the development and validation of the SH-2F Weapons System Trainer, Device 2F106. NAVAIRTESTCEN participates in the program as a technical advisor on flight fidelity. Major contributions are aircraft testing for the establishment of criteria data followed by simulator evaluation, both performed by engineering test pilots and flight test engineers. These evaluations used established and disciplined flight test techniques and should be commonplace in the development and validation of flight trainers. An extensive table of criteria data tests is provided for reference. Typical instrumentation tables for both the aircraft and trainer are included. Specific comments are made concerning trainer testing problems and the priorities of tests. A discussion is included on simulator data-gathering techniques, appropriate parameters, and equipment needed. Finally, the scope of a visual system evaluation is presented, along with a description of its usefulness in additional testing of the basic trainer.