The NC-131H Total In-Flight Simulator (TIFS) is a modified C-131 transport (Convair 580 turboprop airliner). Operated by the Air Vehicles Directorate at Wright-Patterson Air Force Base, it was modified into an in-flight simulator in the late 1960s. TIFS uses a model-following flight control system that controls all aerodynamics control surfaces plus the throttles to achieve independent control of aircraft motions in all six degrees of freedom. Modifications included the addition of a separate evaluation cockpit, side-force surfaces, direct-lift flaps, computer-controlled hydraulic actuators on all control surfaces, and turboprop engines. The aerodynamics and control systems of any aircraft can be programmed on the TIFS' digital computers to produce the proper model responses at the evaluation cockpit.

The TIFS has simulated a wide variety of aircraft, including the B-1, B-2, Space Shuttle, X-29, YF-23, C-130, C-141, and airliners such as the Boeing 7J7, Douglas MD-12X, and Nusantara N250. TIFS also performs generic research and development in the areas of flying/handling qualities, flight control development, and display/human factors. Another TIFS capability allows student test pilots to be instructed in avionics systems test techniques. To perform this mission, the evaluation cockpit is removed and replaced with an interchangeable avionics nose and a modular crew station in the main cabin with seating for two students and an instructor. The avionics suite includes air-to-air/air-to-ground radar, infrared seeker, electro/optical seeker, inertial, low-frequency radio, and global positioning navigation systems. TIFS also can be used in this configuration for avionics system testing.

Most recently, TIFS has been involved in NASA research to develop a cost-effective next-generation supersonic transport. The simulation nose was rebuilt to make room for radar and a large video display. In this configuration, TIFS will allow pilots to evaluate landing a supersonic transport without any forward visibility. The Convair was extensively modified to accommodate the test flights, receiving a new cockpit canopy and nose cap; instrument panel; side and center consoles; rudder pedal and throttle feel systems; and various sensors, displays and instrumentation, including a Silicon Graphics computer and high-definition TV camera and displays.