Spin

A spin is an aggravated stall condition in which the aircraft descends in a helical path while rotating around its vertical axis. During a spin, one wing is more deeply stalled than the other, creating an asymmetric lift condition that sustains the rotation. The aircraft's nose is typically well below the horizon, and the rate of descent is high.

Spin phases:

1. Entry: A stall with yaw (from uncoordinated rudder input, asymmetric power, or a wing drop)
2. Incipient spin: The first 1-2 turns as the spin develops
3. Developed spin: Stable rotation with consistent pitch attitude and descent rate
4. Recovery: Specific control inputs to break the stall and stop the rotation

The standard spin recovery technique (for most aircraft) is: power idle, ailerons neutral, full opposite rudder (against the direction of spin), then forward elevator to break the stall. Once rotation stops, neutralize the rudder and smoothly recover from the resulting dive.

Spin training is required for flight instructor certificates in many countries. Transport category aircraft must demonstrate that they are either spin-resistant or recoverable from spins during certification.