Which flight maneuver should be performed during a slow flight practice?

During slow flight practice, the primary objective is to handle the aircraft at a speed just above the stall threshold while maintaining controlled flight. This maneuver is crucial for developing the pilot's ability to recognize and respond to the aircraft's handling characteristics at low speeds, which is essential for safe landing approaches and go-arounds.

Level flight without stalling involves flying the aircraft at a low airspeed while ensuring it remains controllable and stable. This practice helps pilots understand the limitations of the aircraft, including how to manage pitch and power to prevent stalling while still being proactive about maintaining control.

In contrast, the other options involve scenarios that could introduce greater risks or complexities outside the scope of slow flight training. For example, stalls and steep turns involve more aggressive changes in aircraft attitude and energy state, while descending spirals push the aircraft further towards losing effective control. Single engine operation, although an important skill in multi-engine aircraft, does not align with the focus of slow flight practice.

Thus, performing level flight without stalling during slow flight practice provides the necessary experience to enhance safety and proficiency when operating in low-speed conditions.