The Flying Ireland article gives a good indication of the navigation equipment on-board the Irish S-92s.
It appears to indicate that the FMS system is identical across the fleet but is it possible there might be some small differences between the various aircraft in the fleet? Four aircraft came from the previous UK contract while one came direct from the factory in the USA (having been acquired specifically for the Irish operation).
Also, is the information stored in the FMS of each aircraft identical? If the aircraft are rotated around the various bases after coming in for maintenance, can there be different information stored in each FMS as the crews at a particular base add information to the system as best suited to their needs and the area of the country where they carry out the majority of their flying?
Say, for example, an S-92, having been based at Waterford for a considerable period of time, goes to Dublin for scheduled maintenance. It comes out of maintenance and is assigned to the Dublin SAR operation (R116). Its FMS may contain information optimized for work in the south eastern region of the country (having been inputted by the Waterford crews) and may lack many of the way-points that are programmed into the Shannon or Sligo-based machines by their respective crews. Could the crew of R116 have found themselves flying an unfamiliar aircraft (from an FMS point of view) towards an area they were not familiar with?