Definition
An electronic system of solid-state sensors — typically three-axis accelerometers, gyroscopes, and magnetometers — that continuously measures the aircraft's orientation in space and feeds that data to electronic flight displays. It provides pitch, roll, yaw, and magnetic heading information, replacing the spinning mechanical gyroscopes used in traditional attitude indicators and heading indicators.
Plain English
A small box of electronic sensors that figures out which way the aircraft is pointing — nose up or down, banked left or right, and what direction it is heading — and sends that information to the cockpit displays.
Context Anchor
You will see AHRS discussed in glass-cockpit airplanes, primary flight display system descriptions, and failure procedures for electronic attitude or heading indications.
Derivation
The name describes its two jobs: 'attitude' (the aircraft's orientation in pitch, roll, and yaw) and 'heading' (the direction the nose is pointing). It is a 'reference system' because the displays in the cockpit reference its data to show the pilot what the aircraft is doing.
Why Pilots Care
It supplies reliable attitude and heading information without the vacuum systems or mechanical wear of older gyro instruments, supporting safe instrument flight and reducing maintenance.
Intuition Check
Do not read attitude here as a person’s mood. In this term, attitude means the airplane’s position in the air: nose up or down, and banked left or right.
Example Sentence 1
When the AHRS failed in flight, the pilot's primary flight display lost its attitude information and the pilot transitioned to the standby instruments.
Example Sentence 2
After engine start the AHRS finished its alignment before the aircraft began to taxi.