In cloud or darkness, a pilot cannot tell which way is up. The inner ear lies during acceleration. The attitude indicator solves this by showing the aircraft's pitch and roll relative to the horizon, driven by a gyroscope that stays fixed in space.

The display shows a miniature aircraft against a blue and brown ball. Blue is sky, brown is ground. Bank angles mark the sides, and pitch lines mark climb or descent. Pilots learn to trust the instrument even when their body says otherwise.

Types in service

• Traditional vacuum-driven gyroscopic units
• Electric attitude indicators as backups
• Electronic attitude displays on glass cockpits
• Integrated standby instruments in modern airliners

Failure of this instrument in instrument conditions is an emergency. Without it, a pilot can lose control in minutes, which is why redundancy is mandatory on commercial aircraft.