This research is aimed at the development and application of an immersive virtual reality environment (IVE) for performing assembly and maintenance simulations using the Jack® software package. The Flock of Birds™ motion tracking system is used to capture body postures of an immersed human and reproduce it in real-time in the virtual environment. The Cyberglove™ is used to capture finger movements in real-time for realistic grasp interaction. A comprehensive set of voice commands has been developed to provide significant functionality to allow one person to control the virtual environment while immersed in the environment, thereby improving ease of use and productivity. One of the most important applications is a method by which the immersed human can walk and fly through the virtual environment, thereby greatly expanding the envelope of the virtual environment navigable under the constraints imposed by the limited tracking volume. These capabilities have been used to investigate assembly simulation of the windshield deicer of a Cessna aircraft. After accomplishing successful improvement in fine tuning of the capabilities developed for VR, we aimed at employing the applicability of VR in field of ergonomics. Improvements include improving the ease of use of the capabilities developed so far as well as implementing new types of grasping, etc. One topic of research is the fidelity of the virtual environment in capturing and mapping immersed user postures on to digital humanoids. Different sensor configurations were being analyzed and multiple operators were used to arrive at the general conclusions and recommendations to maximize the accuracy of the postures. We are also implementing certain developments to enable an immersed user to experience the reach, visibility and ergonomics that are experienced by operators of different sizes for any given design of tooling and operations. The motions performed by the immersed operator were mapped to humanoids representing standard operators such as 5th, 50th or 95th percentile males and the postures adopted are subjected to ergonomic analysis.