Abstract: A piloting aid system for ensuring the availability an automatic pilot corresponding to an automatic piloting system and/or a flight director and/or a thrust regulation device to be controlled as a function of a speed information item determined from a source of information, and configured to operate according to a first current guidance mode and an approach capability that are part of a first set of guidance modes and approach capabilities. The system includes a surveillance module to be able to detect the loss of sources of information, a module for determining a second set of guidance modes and of approach capabilities as a function of the source or sources of information whose loss was detected by the surveillance module, a module for use, by the automatic pilot and/or the thrust regulation device, of a second current guidance mode and an approach capability that are part of the second set.