A Hovering Turn is a maneuver performed at hovering altitude in which the nose of the helicopter is rotated either left or right while maintaining position over a reference point on the surface. The maneuver requires the coordination of all flight controls and demands precise control near the surface. You should maintain a constant altitude, rate of turn, and rotor RPM.

Technique

Initiate the turn in either direction by applying antitorque pedal pressure toward the desired direction. It should be noted that during a turn to the left, you need to add more power because left pedal pressure increases the pitch angle of the tail rotor, which, in trun, requires additional power from the engine. A turn to the right requires less power. (On clockwise rotor systems, this is reversed, right turns require more power, and left turns use less.)

As the turn begins, use the cyclic as necessary (usually into the wind) to keep the helicopter over the desired spot. to continue the turn, you need to add more pedal pressure as the helicopter turns to the crosswind position. This is because the wind is striking the tail surfaces and tail rotor area, making it more difficult for the tail to turn into the wind. As pedal pressures increase due to crosswind forces, you must increase the cyclic pressure into the wind to maintain position. Use the collective/throttle to maintain a constant altitude and rotor RPM. Please refer to Figure 9-2.

After the 90 degree position of the turn, you need to decrease pedal pressure slightly to maintain the turn rate. Approaching the 180 degree, or downwind portion, you need to anticipate opposite pedal pressure due to the tail moving from an upwind position to a downwind position. At this point, the rate of turn has a tendancy to increase at a rapid rate due to the weathervaning tendancy of the tail surfaces. Because of the tailwind condition, you need to hold rearward cyclic pressure to maintain the helicopter over the desired spot.

Because of the helicopter's tendancy to weathervane, maintaining the same turn rate from the 180 degree position actually requires you to add some pedal pressure opposite of the direction of the turn. If you do not apply opposite pedal pressure, the helicopter turn rate will increase. The amount of pedal pressure and cyclic deflection throughout the turn depends upon the wind velocity. As ou finish the turn on the upwind heading, apply opposite pedal pressure to stop the turn. Gradually apply forward cyclic pressure to keep the helicoter from drifting.

Control pressures and direction of application change continuously throughout the turn. The most dramatic change is the pedal pressure (and cooresponding power requirement) necessary to control the turn rate as the helicopter moves through the downward portion of the maneuver.

Turns can be made in either direction; However in a high wind condition, the tail rotor may not be able to produce enough thrust, which means that you will not be able to control a turn to the right (counterclockwise rotor system). Therefore: if control is ever questionable, you should make an attempt to make a 90 degree left turn. If sufficient tail rotor thrust exists to turn the helicopter crosswind in a left turn, a right turn can be successfully controlled. The opposite applies to clockwise rotor systems (turn right is questionable control is suspect). Hovering turns should be avoided in winds strong enough to preclude sufficient aft cyclic control to maintain the helicopter over the selected ground reference point while headed downwind. Check the manufacturer's recommendations for this limitation.

Common Errors

Failing to maintain a slow, constant rate of turn.
Failing to maintain position over the selected reference point.
Failing to maintain rotor RPM within the normal operating range.
Failing to maintain a constant altitude.
Failing to use the antitorque pedals correctly.

Hovering turns are another great confidence builder for the novice pilot, especially as you perform them in increasing winds. They will teach you coordination above that required for hovering alone. Remember to anticipate the change in turn rate at the downwind position, and to try a pedal turn (typically left) when control is ever questionable, this is called "Checking Tail Rotor Authority" and can prevent a mishap if you tried a turn to the right and didn't have the power required to stop the turn.


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Page Last Updated on: Nov-06-2017