What are the three phases of a spin?

The three phases of a spin are accurately described as post-stall gyrations, incipient spins, and steady-state spins.

In the context of flight dynamics, the phase of post-stall gyrations occurs when the aircraft has just exceeded its critical angle of attack, leading to an unbalanced aerodynamic condition. During this phase, the aircraft begins to exhibit uncontrolled movements, marking the onset of a spin.

Following this, the incipient spin phase begins when the airplane starts to rotate about its vertical axis, as one wing is more stalled than the other, resulting in a yawing motion. This phase is crucial for recognizing the onset of the spin, as effective recovery actions can still be taken during this time.

Finally, the steady-state spins occur when the aircraft reaches a stabilized spin condition, where the rate of rotation becomes constant and the airplane continues to descend in a spiraling motion. Understanding these phases is critical for pilots to execute an effective recovery and prevent unintended spins during flight.

Overall, this categorization provides a clear understanding of how spins develop and the necessary steps for recovery at each stage.