Fault-Tolerant Air Data Inertial Reference System development results

A new fault-tolerant inertial system architecture is emerging in commercial transport aircraft. This architecture. through sensor skew redundancy and fault tolerant electronics, provides improvement in the integrity, availability and cost of ownership. The system described is a Fault-Tolerant Air Data Inertial Reference System (FT/ADIRS). The system consists of a Fault-Tolerant Air Data Inertial Reference Unit (FT/ADIRU), a Secondary Air Data Attitude Reference Unit (SAARU) and six Air Data Modules (ADM). The FT/ADIRU is fault-tolerant and the SAARU is 100% monitored. The FT/ADIRU includes one additional level of redundancy above that required to dispatch the aircraft. This feature introduces the concept of deferred maintenance. Deferred maintenance allows airlines to schedule FT/ADIRU maintenance at their convenience and eliminates costs due to flight delays and cancellations caused by inertial system failures. The SAARU includes one level of redundancy above that required to provide the basic function. This feature provides fail-safe performance of the SAARU