A Steep Approach is used primarily when there are obstacles in the approach path that are too high to allow a normal approach. A steep approach permits entry into most confined areas and is sometimes used to avoid areas of turbulence around a pinnacle. An approach angle of approximately 15 degrees is considered a steep approach.

Technique

On final approach, head the helicopter into the wind and align it with the intended touchdown point at the recommended approach airspeed (Position 1). When you intercept an approach angle of 15 degrees, begin the approach by lowering the collective sufficiently to start the helicopter descending down the approach path and decelerating (Position 2). Use the proper antitorque pedal for trim. Since this angle is steeper than a normal approach angle, you need to reduce the collective more than that required for a normal approach.

Continue to decelerate with slight aft cyclic, and smoothly lower the collective to maintain the approach angle. As in a normal approach, reference the touchdown point on the windshield to determine changes in approach angle. This point is in a lower position than a normal approach. Aft cyclic is required to decelerate sooner than a normal approach, and the rate of closure becomes apparent at a higher altitude. Maintain the approach angle and rate of descent with the collective, rate of closeure with the cyclic, and trim with the antitorque pedals. Use a crab above 50 feet and a slip below 50 feet for any crosswind that might be present.

Loss of effective translational lift (ETL) occurs higher in a steep approach (Position 3), requiring an increase in the collective to prevent settling, and more forward cyclic to achieve the proper rate of closure. Terminate the approach at hovering altitude above the intended landing point with zero groundspeed (Position 4). If power has been properly applied during the final portion of the approach, very litle additional power is required in the hover.

Common Errors

Failing to maintain proper rotor RPM during the entire approach.
Improper use of collective in maintaining the selected angle of descent.
Failing to make antitorque pedal corrections to comphensate for collective pitch changes during the approach.
Slowing airspeed excessively in order to remain on the proper angle of descent.
Inability to determine when effective translational lift (ETL) is lost.
Failing to arrive at hovering altitude and attitude, with zero groundspeed almost simultaneously.
Low RPM in transition to the hover at the end of the approach.
Using too much aft cyclic close to the surface, which may result in the tail rotor striking the surface.


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Page Last Updated on: Nov-06-2017