When operating at high forward airspeeds, under which conditions are retreating blade stalls more likely to occur?

The conditions that make retreating blade stalls more likely to occur during high forward airspeeds typically involve scenarios where the rotorcraft is affected by increased load and reduced performance characteristics. High gross weight contributes to a higher loading on the rotor blades, making them more susceptible to stalling, particularly when combined with environmental factors like high density altitude and low rotor RPM.

When a helicopter is at high gross weight, the lift required from the rotor blades is significant, leading to a reduction in the effective angle of attack for blades at the retreating side during forward flight. This is exacerbated at high density altitudes where the air is thinner, causing further reductions in available lift.

Additionally, conducting steep turns at these high speeds increases the load factor on the rotor system, which not only demands more lift but also can alter the airflow over the blades, particularly affecting those retreating from the direction of flight. The combination of these factors makes blade stalls more likely to occur, as the retreating blades may exceed their critical angle of attack, leading to a stall.

In summary, the scenario outlined in the chosen answer encapsulates the critical elements—high gross weight, low RPM, high density altitude, and steep turns—that increase the risk of retreating blade