From its discovery, helium had a leading role in many scientific developments. In this chapter, we are interested by its use as a lifting agent for lighter than air vehicles, more specifically unmanned airships. An important application, bridge monitoring, is highlighted in this chapter. The disaster caused by the collapse of one of Minneapolis (Minnesota) highway bridges points to the need for better technologies to inspect bridges. A flight simulator software is first developed then kinematic and dynamic models of this lighter than air vehicle are developed. Finally, the trim trajectories, used in the flight simulator, are detailed and a robust control method introduced.