A few years ago I wrote and published a paper with the American Institute of Aeronautics and Astronautics (AIAA) on how we model the 6-Degrees of Freedom (6-DOF) required for simulating aircraft motion in Microsoft Flight Simulator.

We continue to make improvements from version to version, but the underlying concepts and algorithms used remain constant. I think it's important for our customers (especially developers) to understand that we use the same, high fidelity equations of motion to simulate aircraft behavior that is universally employed throughout the commercial aviation industry. We employ some interesting techniques to improve real-time performance, and to simplify the number of flight model definition parameters that are required.

I've done my best to keep the information as straight-forward and readable as possible, with a good dose of historical information thrown in as well. Check it out.