Definition
An unintentional spin entry, in which an aircraft departs controlled flight and enters an autorotative, stalled descent without the pilot intending it. Typically caused by allowing the airplane to stall while uncoordinated, often as a result of distraction, divided attention, or improper rudder use during slow flight, climbs, or turns.
Plain English
A spin the pilot did not mean to enter. The airplane stalls while the wings are not level or the rudder is misapplied, and instead of just dropping the nose, it begins rotating downward on its own.
Context Anchor
Encountered in training discussions about distractions, stall practice, slow flight, and loss-of-control prevention.
Derivation
Inadvertent comes from the Latin 'in-' (not) and 'advertere' (to turn the mind toward) -- literally 'not having turned the mind to it.' That captures the situation exactly: the pilot's attention was elsewhere when the spin began.
Why Pilots Care
Inadvertent spins account for a high percentage of fatal training accidents because they develop quickly at low altitude where recovery height is limited.
Intuition Check
Do not read spin here as just any accidental turn. In aviation, a spin means the airplane is stalled and rotating downward in a continuing motion until the pilot recovers.
Example Sentence 1
The instructor introduced a realistic distraction during slow flight to show the student how an inadvertent spin can develop when attention drifts from airspeed and coordination.
Example Sentence 2
A momentary distraction while demonstrating a turn resulted in an inadvertent spin at pattern altitude.