Definition
A framework used in aviation instruction that classifies learner mistakes into two broad categories: slips and mistakes. A slip is an error of action — the learner knows what to do but does the wrong thing (for example, reaching for the throttle and grabbing the mixture). A mistake is an error of thought — the learner does what they intended, but the intention itself was wrong (for example, deliberately holding altitude when a descent was required). Recognizing which kind of error occurred determines how the instructor should respond and how the learner should correct it.
Plain English
There are two types of mistakes a student can make: doing the wrong thing by accident when they knew better, or doing the wrong thing on purpose because they thought it was right. Each type needs to be fixed in a different way.
Context Anchor
Seen in instructor training, flight lesson debriefs, and discussions about how to correct student performance.
Derivation
Error comes from the Latin errare, meaning “to wander” or “go astray.” That fits the aviation use: an error is a departure from the intended or correct action, and identifying the kind of error helps bring the learner back onto the right path.
Why Pilots Care
Telling slips and mistakes apart changes how an error gets corrected. A slip is usually fixed with better attention, checklists, or workload management. A mistake means the underlying knowledge or judgment needs to be retaught. Treating one as the other wastes training time and leaves the real problem in place.
Grounding Statement
The point is not to label the student, but to identify why the action went wrong so the correction matches the cause.
Intuition Check
Do not assume “error” simply means carelessness. In this FAA instructor context, the kind of error matters because the cause determines the best correction.
Example Sentence 1
During the debrief, the instructor identified the student's gear-up landing as a slip rather than a mistake, since the student knew the procedure but missed the checklist item.
Example Sentence 2
Identifying the kinds of errors early helped the student clear the confusing terms instead of pushing through and quitting.