What is the purpose of the Attitude Reference Indicator (ARI)?

• A. Provides attitude information only for HUD.
• B. Self-contained pitch and roll attitude reference system with an electrically driven gyro maintains vertical orientation; Provides a minimum of 3 minutes of attitude information with total loss power; Provides backup pitch and roll attitude for use by other systems.
• C. Detects aircraft motion and provides acceleration, velocity, pitch, roll
• D. Synchronizes navigation data across systems

Answer: (B)

The Attitude Reference Indicator provides a self-contained source of attitude information by using an electrically driven gyro to maintain a vertical reference, so pitch and roll data stay available even if the main attitude system loses power. It is designed to deliver a minimum of three minutes of attitude information after total power loss and to supply backup pitch and roll attitude for use by other systems, not just the HUD. This ensures multiple avionics have a reliable attitude reference during outages, which is essential for safe flight. It isn’t mainly about detecting motion and providing acceleration or velocity, nor about synchronizing navigation data across systems, so those broader functions aren’t the ARI’s primary purpose.