J2 Universal Toolkit is a commercial off the shelf software for the design, analysis and modelling of fixed wing aircraft in core design, simulation, flight test and air accident investigation applications. The J2 Universal Toolkit provides a design/modelling/analysis solution that can integrate any legacy data or code into a powerful analytical engine, enhancing the visualisation, speed and fidelity of the aircraft analysis/evaluation process. J2 aircraft models can be flown in any simulator platform from desktop to full mission simulators and can be changed and evaluated in real time. The Universal Toolkit can put a pilot in the loop at any stage in an evaluation process, testing and running handling variations and operational changes, accelerating the move towards certification. J2 already delivers accelerated design process and reductions in re-work. In Flight Test the j2 software can dramatically cut the flight matching phase and can be used as a fligh ttest rehearsal toolset also. Most recently j2 Universal Toolkit has been adopted in air accident flight physics based investigations and this has already been recognised through the announcement of key US based alliances with technical leaders in both Air accident investigation and fligh test programme delivery.