Flight simulators used for the training of flying skills must receive careful scrutiny regarding the fidelity of the flight dynamics simulation. If the goal of the training simulator is to improve pilot flying skills and eliminate bad habits, then relatively high fidelity standards must be imposed on the design and validation of the flight dynamics simulation. Lower standards may be suitable only if pilot flying skill training is not a primary goal, if only to ensure that the pilot's flying workload does not interfere with the primary training activities, such as sensor operation. Either way, training simulator requirements must express flight fidelity performance goals in explicit terms to ensure that the desired training capability will be achieved. The commonly accepted method for expressing flight fidelity performance requirements is to cite specific aircraft flight characteristics in terms of the tests and parameters obtained through established aircraft flight test practices. A trainer specification typically lists tolerance values to express how closely the simulation must match the aircraft flight test data. For USN/USMC fixed and rotary wing flight trainers, a body of knowledge and experience has built up over the last two decades on how to define and achieve high flight fidelity through the combined efforts of knowledgeable aeronautical engineers and flight test pilots and engineers from both contractor and government teams. As a result of this joint process, a set of tolerances for military flight trainers that is comprehensive and stringent (but achievable) has evolved within Naval Air Warfare Center (NAWC) to ensure that military pilot training needs are met.

The military acquisition community assesses parallel commercial practices in the quest of increased cost effectiveness, and trainer flight fidelity is no exception. Aircraft data requirements for airline transport aircraft are well documented and the Federal Aviation Administration (FAA) has established guidelines for a process to officially certify devices for commercial pilot training applications. Recent military trainer acquisition programs have applied commercial guidelines instead of the comprehensive NAWC tolerances. The result is that important military pilot training tasks, such as maneuvering flight and stall recovery, may not be trainable in the simulator. This paper will describe the differences between military flight fidelity requirements and commercial practices to show where they are equivalent and where they are not. In particular, the military pilot training tasks compromised by the use of FAA Advisory Circulars 120-40B and 120-63 will be addressed, with particular emphasis on fixed wing applications. The paper will suggest guidelines for blending the most appropriate parts of the FAA Advisory Circulars with the necessary parts of the NAWC military flight fidelity requirements.