The entrainment and circulation of ground debris by rotorcraft downwash over unprepared fields, often referred to as "brownout", represents a critical safety issue for rotary-wing aviation today. Helicopter pilots often first experience brownout in actual flight conditions, and it is desirable to advance the state of training simulations by providing high fidelity modeling of brownout conditions during landing and take-off. While semi-empirical brownout visual models are available in training simulators, these models lack the level of fidelity required to capture the complex interaction of rotor downwash, ambient winds, and the effect of vehicle maneuvering, in combination with debris transport and visual obscuration effects due to the wide range of possible surface cover materials and ground topology. This paper describes the development and integration of an advanced, physics-based model of rotorcraft brownout for piloted simulation. A central element to the model is an advanced rotorwash model based on real-time, free vortex wake methods to represent the complex flow field of maneuvering rotorcraft in the proximity of the ground. This rotorwash model is combined with debris entrainment and transport models to determine the visible obscuration effects of brownout based on physical principles. The models are incorporated into a real-time module that has been integrated into the U.S. Army Advanced Prototyping Engineering and Experimentation (APEX) laboratory rotorcraft flight simulation for the UH-60M, CH-47F and ARH aircraft and image generator system at the System Simulation and Development Directorate at Redstone Arsenal in Huntsville, AL. This paper provides an overview of the brownout model and validation, and describes the software architecture, integration approach, and results from this successful integration.