sevenstrokestroll, based on you experience, in case of ground/air sensor failure, what other indications (if any) beside "RAT probe overheat" are given to deck or somewhere else ?
Also what is the flow (must be indicated in the maintenance manuals I guess) that a trained engineer shall follow in presence of the alarm above. It seem obvious that the working of the air/ground logic must be confirmed before assuming the heating system is faulty, and a certfied engineer would follow this logic even without consulting the manual.