Quick Stop Helicopter Maneuver

An interesting maneuver to try in this new configuration is the sudden deceleration, or "quick stop": you pull back sharply on the cyclic while dropping the collective and pressing the right pedal (for US helicopters) to compensate for reduced torque, which keeps the nose straight. The maneuver requires a high degree of coordination of all controls. so is a good test of your control arrangement's maximum travel capabilities. You start at an altitude that gives you a safe clearance between the tail rotor and the surface -- typically about 30 feet. When you pull back on the collective, the nose goes way up, putting the entire rotor disk into a braking position. Once stopped, you recover and slowly descend to a hover by pulling up smoothly on the collective while bringing the cyclic to level and centering the pedals. 

Even though the stop is "sudden", you make all control inputs steady and smooth. When you can decelerate from about 50 knots to zero without losing altitude or changing heading, you've perfected the maneuver. This maneuver is on the private pilot check ride, and ensures that you can stop to avoid a sudden obstruction, such as conflicting traffic, at low altitude, for example while starting a take-off run. Here's a schematic of the quick stop: http://www2.anac.gov.br/anacpedia/img/quickstop.png

VI. AREA OF OPERATION: PERFORMANCE MANEUVERS 

NOTE: The examiner shall select TASK A and at least one other
TASK. A. TASK: RAPID DECELERATION
REFERENCES: FAA-H-8083-21; POH/RFM.
Objective. To determine that the applicant: 
1. Exhibits knowledge of the elements related to rapid deceleration.
2. Maintains RPM within normal limits.
3. Properly coordinates all controls throughout the execution of the maneuver.
4. Maintains an altitude that will permit safe clearance between the tail boom and the surface.
5. Decelerates and terminates in a stationary hover at the recommended hovering altitude.
6. Maintains heading throughout the maneuver, ±10°.

https://www.faa.gov/training_testing/testing/test_standards/media/FAA-S-8081-15a.pdf

Thanks to Packet guy for helping us to gather this intofmation.