Definition
An attitude indicator pitch correction in which the miniature aircraft is repositioned by an amount equal to the width of one horizon bar (the small reference bar on the attitude indicator) relative to the artificial horizon line. It is the standard initial pitch input used to recover when an altitude deviation is greater than 100 feet.
Plain English
When you've drifted more than 100 feet off your assigned altitude, your first pitch correction is to move the little aircraft symbol on the attitude indicator up or down by the thickness of one of its reference bars.
Context Anchor
Seen in instrument flying when using the altimeter with the attitude indicator to return to an assigned altitude.
Derivation
Here, “bar” means a straight reference mark on an instrument face. That helps because the correction is not a guess or a large control movement; it is measured against the pitch bars shown on the attitude indicator.
Why Pilots Care
Provides a quick, consistent way to return to assigned altitude and reduces the chance of prolonged altitude busts in instrument conditions.
Grounding Statement
When the altitude error is more than 100 feet, start with one clear pitch-bar change rather than a tiny nudge or a large pitch change.
Intuition Check
“One bar” does not mean one standard amount on every aircraft or every display. It means using one pitch reference bar on the attitude indicator you are flying as the initial visual guide for the correction.
Example Sentence 1
When she noticed the altimeter showed 150 feet low, she made a one bar correction on the attitude indicator to begin climbing back to altitude.
Example Sentence 2
For deviations greater than 100 feet the checklist calls for a one bar correction first, followed by smaller attitude adjustments to capture the altitude precisely.