What data is lost when ATT mode is selected on the ADIRU?

What data is lost when ATT mode is selected on the ADIRU?

• A. Attitude data
• B. Magnetic heading
• C. Rate of turn
• D. Position data

Answer: (D)

ADIRU (the inertial reference unit) can operate in modes that decide what data it outputs for navigation. In ATT mode, the system is focused on providing attitude reference using purely inertial data. It keeps pitch and roll information and the heading derived from the inertial sensors, but it does not produce or update the aircraft’s position. Position data requires navigation calculations that combine inertial data with external updates (like GPS or other nav sources), which are not active in this mode. So, when ATT mode is selected, the data that gets lost is the position data. The attitude and heading remain useful for attitude reference, but the navigation position reference is not provided in this mode.

ADIRU (the inertial reference unit) can operate in modes that decide what data it outputs for navigation. In ATT mode, the system is focused on providing attitude reference using purely inertial data. It keeps pitch and roll information and the heading derived from the inertial sensors, but it does not produce or update the aircraft’s position. Position data requires navigation calculations that combine inertial data with external updates (like GPS or other nav sources), which are not active in this mode. So, when ATT mode is selected, the data that gets lost is the position data. The attitude and heading remain useful for attitude reference, but the navigation position reference is not provided in this mode.