While aircraft can move in three dimensions there is an added component when we have to consider where we are going with relation to the ground. The ability to control the groundpath has several different levels. Initially we are concerned with flying a standard circuit so that we can conform to the normal circuit traffic and planning requirements. At this stage there are a lot of visual cues that help us with this task. Even in the absence of landmarks, the runway is usually straight and we can readily discern the effects of the winds on the desired path. The appropriate corrections are made by use of crabs or sideslips. While a standard circuit is desired, with gliders often more dramatic corrections have to be made to the groundpath by altering the standard circuit. Knowledge of glidepath and groundpath are intimately linked in this environment.
Later in the gliding experience, groundpath control becomes more important outside of the circuit. At the intermediate and advanced stages controlling the effects of the wind properly allows entry into a standard circuit. Here the visual cues used to control the groundpath are generally objects on the horizon and any other straight lines such as roads which can be used to judge the correct crab angle. There is more emphasis at these stages on the progress made over time, and the corrections are usually a bit more subtle.
Pilots flying cross-country need to refine these skills and use a combination of the fundamental flying skills using visual references in conjunction with navigation aids. Flight planning, the compass, GPS, and maps are cross-referenced to fly the proper ground path. Pilots should learn that as with speed control, using a good visual cue such as an angle with respect to a road is important to lower the workload. The compass, GPS, and maps are good for checkpoints, but the minute-to-minute flying should be done with something that appears in the ‘heads-up display’.