Definition
Gyroscopic instruments — commonly called gyros — are flight instruments that rely on a rapidly spinning rotor to sense aircraft attitude, heading, or rate of turn. The three primary gyro instruments in a traditional cockpit are the attitude indicator, the heading indicator, and the turn coordinator (or turn-and-slip indicator). Gyros may be powered by engine-driven vacuum or pressure systems, by electrical power, or, in modern aircraft, replaced by solid-state sensors that perform the same function electronically.
Plain English
Gyros are the cockpit instruments that tell the pilot which way the aircraft is pointing and whether it is banking, climbing, or turning. They work because something inside is spinning very fast, and a fast-spinning object resists changes to its position — that resistance is what the instruments measure.
Context Anchor
Seen during the after-engine-start instrument check, when the pilot confirms the gyro instruments have power, have settled, and are showing reasonable indications before taxi.
Derivation
From the Greek 'gyros,' meaning 'circle' or 'turn.' The name fits because the heart of each instrument is a wheel spinning in a circle at high speed.
Why Pilots Care
They supply continuous attitude and heading data critical for safe flight in clouds or at night when outside references disappear.
Grounding Statement
Right after engine start, a gyro may need a short moment to spin up and settle before its reading is dependable.
Intuition Check
Do not assume gyros means a navigation system by itself. In this checklist context, it means instruments or units that use a spinning reference to show aircraft position, direction, or turning.
Example Sentence 1
After engine start, the pilot allowed time for the gyros to come up to speed before checking the attitude indicator and heading indicator for correct readings.
Example Sentence 2
Loss of the gyros in instrument conditions requires immediate transition to partial-panel procedures.