The Boeing 777 Fault Tolerant Air Data and Inertial Reference System-a new venture in working together

The Boeing Commercial Airplane Group has certified an all-new, integrated Fault Tolerant Air Data and Inertial Reference System (FT-ADIRS) on its 777 airliner. The FT-ADIRS consists of the Fault Tolerant Air Data and Inertial Reference Unit (FT-ADIRU), the Secondary Attitude and Air Data Reference Unit (SAARU), and six Air Data Modules (ADMs). New processes for the design, verification, and validation of the system were developed. The FT-ADIRS redundancy management and system performance were validated using a unique process whereby flight-recorded sensor data were replayed through actual production units. Faults were inserted in a Monte Carlo fashion to demonstrate the ability of the inertial navigation and air data functions to isolate and survive sensor faults in real-time.