Which phenomenon can cause main rotor disk interference?

The phenomenon that can cause main rotor disk interference is referred to as "Loss of Tail Rotor Effectiveness" (LTE). This condition occurs when certain flight parameters create a situation where the tail rotor's ability to counteract the torque produced by the main rotor is diminished. Specifically, LTE often arises in specific situations such as high-density altitudes, low airspeeds, and high rates of descent. When the tail rotor enters a region of disturbed airflow caused by the main rotor's wake, it may lose its effectiveness, leading to uncontrolled yawing. This interference between the main rotor and tail rotor can lead to dangerous scenarios if not managed correctly.

Other options, while related to helicopter flight dynamics, do not specifically refer to the interference between the rotors. Ground effect refers to the increased lift and decreased drag experienced by the rotor system when flying close to the ground but does not cause rotor interference. Rotor blowback is related to the behavior of the rotor blades under certain conditions but does not directly lead to interference issues. Descent rate primarily concerns vertical movement rather than the interaction between the rotor systems. Hence, LTE is the most pertinent phenomenon affecting main rotor disk interference.