Which component is responsible for the flight guidance information exchange in DUAL mode?

The component responsible for the flight guidance information exchange in DUAL mode is the Flight Management and Guidance Computer (FMGC). The FMGC integrates various systems to ensure that the aircraft's autopilot and flight director commands are effectively coordinated.

In DUAL mode, the FMGC utilizes inputs from both flight management computers to enhance redundancy and reliability in flight guidance. This ensures that if one system fails or provides incorrect data, the other can continue to provide accurate flight information, which is critical for safe aircraft operation.

The Primary Flight Display (PFD) and Navigation Display (ND) serve to present this information to the flight crew but do not themselves manage or exchange the flight guidance data. The Air Data Inertial Reference Unit (ADIRU) provides essential data regarding the aircraft’s position, attitude, and performance but does so in support of the FMGC, rather than facilitating the guidance information exchange directly. Therefore, the FMGC is the key component for flight guidance information exchange in DUAL mode.