What is the primary cause of an inadvertent spin according to flight training guidelines?

The primary cause of an inadvertent spin, according to flight training guidelines, is exceeding critical angle of attack (AOA) combined with improper use of the rudder. When an aircraft exceeds its critical AOA, it enters a stall condition where airflow separates from the wing, leading to a loss of lift. If a pilot does not coordinate recovery efforts—particularly through correct rudder input during this phase—they may inadvertently cause the aircraft to enter a spin.

Improper rudder use can exacerbate the situation by causing one wing to stall more than the other, which initiates a rotational motion characteristic of a spin. This highlights the importance of understanding both the aerodynamic principles that lead to a stall and the necessary coordinated control inputs to maintain aircraft control during critical phases of flight.

The other options do touch on factors that could impact flight safety, but they do not directly address the mechanics of spin entry as clearly as the critical AOA and rudder relationship does. For example, loss of engine power typically leads to issues such as controlled descent or glide path rather than a spin, and strong crosswinds affect takeoff and landing stability, while improper weight distribution primarily influences aircraft balance and handling during flight, but is not a direct cause of spins.