Definition
A noticeable, often abrupt shift in a student's emotional state during training — for example, swinging from cheerful to withdrawn, from confident to irritable, or from engaged to apathetic — that is significant enough to stand out from the student's normal behavior. In the context of abnormal reactions to stress, marked changes in mood are one of the warning signs that a student may not be coping with the demands of flight training and may need closer attention or, in some cases, professional help.
Plain English
Big, obvious changes in how a student feels and acts — happy one moment, upset or shut down the next — that are clear enough for an instructor to notice.
Context Anchor
An instructor may notice marked changes in mood during a flight lesson, a ground lesson, or a stressful training event.
Derivation
"Marked" here means clearly noticeable or pronounced — not subtle. It comes from the idea that the change leaves a visible "mark" on the student's behavior. Knowing this helps the instructor understand the FAA is talking about changes obvious enough to stand out, not minor day-to-day variations.
Why Pilots Care
These changes can impair judgment and increase risk, so recognizing them helps decide whether a pilot should fly or seek support.
Intuition Check
Marked does not mean a small mood change or a casual observation. Here it means a clear, noticeable change from the student's normal emotional state.
Example Sentence 1
The instructor noted marked changes in mood in his student over several lessons and decided to have a conversation before continuing with new maneuvers.
Example Sentence 2
Marked changes in mood during a long cross-country may signal accumulating stress and warrant a break or return to base.