Many airborne imaging systems contain two or more sensors, but they typically only allow the operator to view the output of one sensor at a time. Often the sensors contain complimentary information which could be of benefit to the operator and hence there is a need for image fusion. Previous papers by these authors have described the techniques available for image alignment and image fusion. This paper discusses the implementation of a real-time image alignment and fusion system in a police helicopter. The need for image fusion and the requirements of fusion systems to pre-align images is reviewed. The techniques implemented for image alignment and fusion will then be discussed. The hardware installed in the helicopter and the system architecture will be described as well as the particular difficulties with installing a 'black box' image fusion system with existing sensors. The methods necessary for field of view matching and image alignment will be described. The paper will conclude with an illustration of the performance of the image fusion system as well as some feedback from the police operators who use the equipment.