In terms of aerodynamics, the wind affects the magnitude of the effective relative airflow and the effective angle of attack. When a helicopter flies in headwind conditions, then the headwind component is added to the helicopter's forward airspeed and as a result the effective angle of attack is greater, producing more lift and thrust.

In terms of performance, when thrust is multiplied by TAS, equals to Power available. So, the greater the thrust, the greater the Power available and as a consequence the better the Performance.

Therefore:

• In headwind conditions, Power available is greater, thus, Performance increases.
• In tailwind conditions, Power available is less, thus, Performance decreases.