With the emergence of Grid computing and service-oriented architectures, computing is becoming increasingly less confined to traditional computing platforms. Grid computing promises the accessibility of vast computing and data resources across geographically dispersed areas. This capability is significantly enhanced by establishing support for mobile wireless devices to deliver access to high-performance computing under demanding circumstances. Access to the Grid from mobile devices can be very effective in business environments where users can access the vast computing power and data repositories on the Grid while working out on the field. This also enables and encourages collaborative working environments. A Grid demonstrator system for distributed aircraft health monitoring already developed and implemented in the UK E-Science Grid project, DAME, is introduced. In this demonstrator, CBR technology for decision support is implemented in a practical framework that enables Grid-based, proactive mobile computing.