Standby instrument system

An augmented air data and inertial reference system (AADIRS) serving as a standby instrument on an aircraft is provided. A secondary air data and inertial reference system (ADIRS) includes a secondary air data module coupled to a secondary inertial reference module. The secondary air data and inertial reference system is configured to derive secondary air data and inertial reference data using the secondary air data module and the secondary inertial reference module. The secondary inertial reference system is further configured to provide the second air data and inertial reference data to a flight control system for use as a backup source of data for control of the aircraft. A graphics module is coupled to the secondary air data and inertial reference system and a display. The graphics module is configured to receive the secondary air data and inertial reference data and process the secondary air and inertial reference data.