Which situation can indicate that LTE is occurring?

The situation indicating that Loss of Tail Rotor Effectiveness (LTE) is occurring is primarily characterized by an uncommanded yaw, particularly towards the right. This phenomenon typically arises under specific flight conditions, which can cause the helicopter to experience a loss of the directional control provided by the tail rotor.

LTE can occur due to various factors such as the helicopter's airspeed, the angle of the tail rotor’s attack, and the prevailing wind conditions. When the tail rotor is unable to counteract the torque produced by the main rotor, which usually happens when the helicopter is operating close to the limits of its flight envelope or in specific environmental situations, the aircraft will yaw uncontrollably. The right yaw is typically observed because, in most helicopters, the main rotor's torque causes the tail to move in that direction.

In contrast, increasing forward airspeed generally helps improve the effectiveness of the tail rotor by allowing for better airflow over the rotor blades, making it less likely for LTE to develop. A decrease in rotor RPM usually contributes to a variety of aerodynamic issues but is not a direct indication of LTE. Likewise, a stable helicopter heading would suggest that the aircraft is under control and not experiencing LTE, as there would be no uncommanded yaw or instability in flight