Refer to figure.
Flare is the most effective method to decelerate from forward speed to zero. The Flare is initiated by moving the cyclic control rearwards. This tilts the disc, thus the Total Rotor Thrust (TRT) vector rearwards and pitches up.

The characteristics of the flare effect include:

• Thrust reversal: The disk is tilted in the opposite direction to that of the helicopter’s travel, and the TRT now points in the same direction as the parasite drag vector. The nose will pitch up.
• Increase in TRT: The airflow from underneath increases the angle of attack and TRT.
• Increased rotor RPM in spite of the increased angle of attack and drag because:

1. Collective is lowered as you try not to climb avoiding ballooning.
2. The increased TRT makes the coning angle to increase. Due to the Coriolis Effect, the reduced radius of the tip path plane increases the rotor RPM and an overspeed may occur.
3. Increased load factor.
4. Application of non-power pedal may be required for directional control.