An extreme aft longitudinal center of gravity (CG) during cruise can have several impacts on helicopter flight dynamics:

1. Cyclic Stick Position: With an aft CG, the cyclic stick will need to be positioned closer to its forward limit to maintain level flight. This is because the helicopter becomes tail-heavy, requiring the rotor disk to tilt forward to compensate for the rearward weight bias. The closer the cyclic is to its forward stop, the less control authority remains, which could be critical in certain situations (e.g., gusty conditions or during sudden maneuvers).

2. Increased Stress on the Rotor Head: Operating with an aft CG increases stress on the rotor head and components. The rotor system has to work harder to maintain stability and level flight, as it needs to produce compensatory forces to counterbalance the tail-heavy configuration. This can lead to increased wear and potentially accelerate component fatigue.

Maintaining proper CG balance is crucial for safe and efficient helicopter operation, as extremes in either direction (forward or aft) can compromise both flight performance and safety.