Definition
Unintended deviations from the assigned or desired magnetic heading during straight-and-level flight, typically caused by failure to cross-check the heading indicator, allowing the aircraft to drift in yaw or roll, or applying uncoordinated control inputs that produce a turn the pilot did not intend.
Plain English
Times when the aircraft is no longer pointing the way the pilot meant it to point. The nose has drifted off the chosen direction, usually because the pilot stopped checking the heading instrument or let a small bank go uncorrected.
Context Anchor
Seen in instrument flying when practicing straight-and-level flight and trying to hold a steady heading using the flight instruments.
Derivation
Heading comes from the idea of the aircraft’s head or nose pointing in a direction. Error comes from a Latin word meaning to wander, which fits the aviation use: the aircraft’s direction has wandered away from where it should be.
Why Pilots Care
Uncorrected heading errors increase workload, cause course deviations, and can lead to navigation problems or airspace incursions in instrument conditions.
Intuition Check
Heading does not mean the route you plan to fly or the line drawn on a chart. Here it means the direction the aircraft’s nose is pointing right now.
Example Sentence 1
The instructor pointed out that most of the student's heading errors were caused by fixating on the altimeter and forgetting to scan the heading indicator.
Example Sentence 2
Small heading errors are common when a pilot fixates on one instrument and neglects the heading indicator.