What is the primary risk of flying inside the HV curve during autorotation?

The primary risk of flying inside the height-velocity (HV) curve during autorotation relates to the reduced chances of executing a safe autorotation. The HV curve is a critical concept in helicopter flight training, which outlines the safe zones for operating a helicopter concerning altitude and airspeed.

When operating within the HV curve, a pilot may not have sufficient vertical speed or forward airspeed to achieve a safe landing in the event of an engine failure. This area indicates that if the helicopter were to lose engine power, the pilot would be unable to maintain the necessary control and energy management needed to safely glide to the ground.

For instance, at low heights and low velocities, the helicopter might not have enough time or altitude to execute the required maneuvers to glide safely to a landing. In contrast, staying outside of the HV curve—either climbing or at an appropriate horizontal speed—keeps the helicopter within safe operational limits, enhancing the chances of controlling the descent and achieving a safe landing during an autorotation.

Understanding this risk helps pilots make informed decisions about their approach and landing techniques, emphasizing the importance of maintaining situational awareness regarding current flight conditions and helicopter performance.