Imaginary centerline Reference point Wind Figure 9-20.  Plan the turn to final so the helicopter rolls out on an  imaginary extension of the centerline for the final approach path.  This path should neither angle to the landing area, as shown by  the helicopter on the left, nor require an S-turn, as shown by the  helicopter on the right.  Common Errors Normal Approach to a Hover Technique terminate at the hover altitude with the rate of descent and  groundspeed reaching zero at the same time. Approaches  are categorized according to the angle of descent as normal,  steep, or shallow. In this chapter, concentration is on the  normal approach. Steep and shallow approaches are discussed  in the next chapter. Use the type of approach best suited to the existing conditions.  These conditions may include obstacles, size and surface of  the landing area, density altitude, wind direction and speed,  and weight. Regardless of the type of approach, it should  always be made to a specific, predetermined landing spot. A normal approach uses a descent angle of between 7° and  12°. On final approach, at the recommended approach airspeed  and at approximately 300 feet AGL, the helicopter should  be on the correct ground track (or ground alignment) for the  intended landing site, but the axis of the helicopter does not  have to be aligned until about 50-100 feet AGL to facilitate  a controlled approach.  [Figure 9-20]  Just prior to reaching  the desired approach angle, begin the approach by lowering  the collective sufficiently to get the helicopter decelerating  and descending down the approach angle. With the decrease  in the collective, the nose tends to pitch down, requiring  aft cyclic to maintain the recommended approach airspeed  attitude. Adjust antitorque pedals, as necessary, to maintain  trim. Pilots should visualize the angle from the landing  point to the middle of the skids or landing gear underneath  them in the cockpit and maneuver the helicopter down that  imaginary slope until the helicopter is at a hover centered  over the landing point or touching down centered on the  landing point. The most important standard for a normal  approach is maintaining a consistent angle of approach to  the termination point. The collective controls the angle of  approach. Use the cyclic to control the rate of closure or how  fast the helicopter is moving towards the touchdown point.  Maintain entry airspeed until the apparent groundspeed and  rate of closure appear to be increasing. At this point, slowly  begin decelerating with slight aft cyclic, and smoothly lower  the collective to maintain approach angle. Use the cyclic to  maintain a rate of closure equivalent to a brisk walk. At approximately 25 knots, depending on wind, the helicopter  begins to lose effective translational lift. To compensate for  loss of effective translational lift, increase the collective to  maintain the approach angle, while maintaining the proper  rpm. The increase of collective pitch tends to make the nose  rise, requiring forward cyclic to maintain the proper rate of  closure. As the helicopter approaches the recommended hover  altitude, increase the collective sufficiently to maintain the  hover. Helicopters require near maximum power to land  because the inertia of the helicopter in a descent must be  overcome by lift in the rotor system. At the same time, apply  aft cyclic to stop any forward movement while controlling  the heading with antitorque pedals. 1.  Failing to maintain proper rpm during the entire  approach. 2.  Improper use of the collective in controlling the angle  of descent. 3.  Failing to make antitorque pedal corrections to  compensate for collective changes during the  approach. 4.  Maintaining a constant airspeed on final approach  9-19