An Approach is the transition from the traffic pattern altitude to either a hover or to the surface. The approach should terminate at the hover altitude withthe rate of descent and groundspeed reaching zero at the same time. Approaches are categorized according to the angle of descent; Normal, Steep, or Shallow. The normal approach to a hover and to the surface will be covered here. Steep and Shallow (Running Landings) approaches are covered in a separate topic.

You should 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 velocity, and weight. Reguardless of the type of approach, it should be made to a specific, predetermined landing spot.

NORMAL APPROACH TO A HOVER

A Normal Approach to a Hover uses a descent profile of between 8 and 12 degrees starting at approximately 300 feet AGL.

Technique

On final approach, at the recommended approach airspeed and at approximately 300 feet AGL, align the helicopter with the point of intended touchdown.

After intercepting an approach angle of 8 - 12 degrees, 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 the antitorque pedals, as necessary, to maintain longitudinal trim. You can determine the proper approach angle by relating the point of intended touchdown to a point on the helicopter windshield.

The collective controls the angle of approach. If the touchdown point seems to be moving up on the windshield, the angle is becoming shallower, necessatating a slight increase in collective. If the touchdown point moves down on the windshield, the approach angle is becoming steeper, requiring a slight decrease in collective.

Use the cyclic to control the rate of closure or how fast you are moving toward the touchdown point. Maintain enrty 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 to 40 feet AGL, depending on wind, the helicopter begins to lose effective translational lift (ETL). To comphensate for the loss of ETL, you must 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, you need to increase the collective sufficiently to maintain the hover. At the same time you need to apply aft cyclic to stop any forward movement, while controlling the heading with the antitorque pedals.

Common Errors

Failing to maintain proper rotor RPM during the entire approach.
Improper use of the collective in controlling the angle of descent.
Failing to make antitorque pedal corrections to comphensate for collective changes during the approach.
Failing to simultaneously arrive at hovering altitude and attitude with zero airspeed.
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 tail strikes.

NORMAL APPROACH TO THE SURFACE

A Normal Approach to the Surface or no-hover landing is used if loose snow or dusty surface conditions exist. These situations could cause severly restricted visibility, or the engine could possibly ingest debris when the helicopter comes to a hover. The approach is the same as the normal approach to a hover; however, instead of terminating at a hover, continue the approach to touchdown. Touchdown should occur with the skids level, zero groundspeed, and a rate of descent approaching zero.

Technique

As the helicopter nears the surface, increase the collective, as necessary, to cushion the landing on the surface, terminate in a skids-level attitude with no forward movement.

Common Errors

Terminating at a hover, then making a vertical landing.
Touching down with forward movement.
Approaching too slow, requiring the use of excessive power during the termination.
Approaching too fast, causing a hard landing.

CROSSWIND CONSIDERATIONS DURING APPROACHES

During A Crosswind Approach, you should crab into the wind. At approximately 50 feet of altitude, use a slip to align the fuselage withthe ground track. Ther rotor is tilted into the wind with cyclic pressure so that the sideward movement of the helicopter and wind drift counteract each other. Maintain the heading and ground track withthe antitorque pedals. This technique should be used with any type of crosswind approach, whether it is shallow, normal or steep.

GO-AROUND

A Go-Around is a procedure for remaining airborne after an intended landing is discontinued. A go-around may be necessary when:

Instructed by a Control Tower.
If a traffic conflict occurs (in-flight traffic or traffic on the surface).
Any time you feel the approach cannot be completed safely. This is discussed below.

A good rule of thumb to use during an approach is to make a go-around if the helicopter is in a position from which it is not safe to continue the approach. Anytime you feel an approach is uncomfortable, incorrect, or potentially dangerous; Abandon the Approach. The decision to make a go-around should be positive and initiated before a critical situation develops. When the decision is made, carry it out without hesitation. In most cases, when you initiate a go-around, power is at a low setting. Therefore your first response is to increase collective to takeoff power. This movement is coordinated with the throttle to maintain RPM, and the proper antitorque pedal input to control heading. Then, establich a climb attitude and maintain climb airspeed to go around for another approach.


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Page Last Updated on: May-29-2002