What region allows additional collective pitch during the flare prior to touchdown in autorotation?

The correct answer is the Overtravel Region. This area is critical during the flare phase of autorotation. When a helicopter is in autorotation, particularly as it approaches landing, the pilot can increase collective pitch to reduce the descent rate and improve the deceleration before touchdown. The Overtravel Region allows for this additional collective pitch, which enhances the helicopter's ability to control its descent and cushion the landing.

The Overtravel Region is specifically designed to give pilots the ability to manage lift and descent rates effectively, ensuring a smoother transition from the autorotation to a landing. Understanding how to utilize this region is vital for maintaining control and ensuring safety during emergency landings.

In contrast, other regions such as the Flight Control Region primarily deal with normal flight maneuvers and do not necessarily provide the flexibility needed for additional collective pitch during the critical flare phase. The Collective Pitch Zone and Descent Region also do not highlight the increased collective pitch capability in the context of the autorotation flare, making them less relevant to this particular operational scenario.