The present disclosure relates to health monitoring and maintenance of mobile platforms such as aircraft. In particular, onboard apparatus and methods and also ground-based apparatus and methods that cooperate in assisting with the maintenance of mobile platforms by facilitating diagnosis of events detected onboard mobile platforms while such mobile platforms are in operation (e.g., transit, flight) are disclosed. In various aspects, the present disclosure discloses apparatus and methods for handling and reporting the detection of events onboard mobile platforms, reporting predefined additional information associated with the event upon request from a ground facility, identifying one or more potential causes for the detected event and determining the occurrence probability for each potential cause identified.