Analytical redundancy involves the use of diagnostic routines in software to detect a fault in a set of sensor signals. The fault detection algorithms and associated redundancy management structure are presented within. The DIGIT AC application improved the mission reliability of existing dual mission-essential sensors by effecting a single-fail-operative capability. Flight safety was preserved for single sensors. Fault detection qualities of the diagnostics were satisfactory. False alarm problems required considerable redesign and tuning to properly model the processes. These problems were satisfactorily solved with the exception of diagnostic errors occurring during extreme turbulence (e.g., penetration of jetwash).