and finding lift. This can lead to a dangerous habit of focusing  too much time inside the cockpit rather than scanning outside  for traffic. Like any electronic instrument, GPS units can fail,  so it is important to have a backup for navigation, such as a  sectional and plotter. The number one rule of safe cross-country soaring is always  stay within glide range of a suitable landing area. The  alternate landing area may be an airport or a farmer’s field.  If thermaling is required just to make it to a suitable landing  area, safe cross-country procedures are not being practiced.  Sailplane pilots should always plan for high sink rates  between thermals as there are always areas of sink around  a lifting thermal to fill in the void vacated by the lifting air. Before venturing beyond gliding distance from the home  airport, thermaling and cross-country techniques can be  practiced using small triangles or other short courses. Three  examples are shown in  Figure 11-10 . The length of each  leg depends on the performance of the glider, but they are  typically small, around 5 or 10 miles each. Soaring conditions  do not need to be excellent for these practice tasks but should  not be so weak that it is difficult just to stay aloft. On a good  day, the triangle may be flown more than once. If other  airports are nearby, practice finding and switching to their  When using the glide calculator tool, keep in mind that these  calculations account for only the glider’s calm air rate of  descent. Any sink can drastically affect these calculations  and make them worthless. In times of good lift, there will  also be areas of strong sink. A sailplane pilot must learn to  read the sky to find the lift and avoid or pass through the sink  as quickly as possible. Time in lift is good and time in sink  is bad. A good sailplane pilot will be thoroughly aware of  that particular sailplane’s polar curves and the effects from  different conditions of lift, sink, and winds. It is important to develop skill in quickly determining  altitude needed for a measured distance using one of the  glide calculator tools. For instance, while on a cross-country  flight and over a good landing spot with the next good  landing site a distance of 12 miles into a 10-knot headwind.  [Figure 11-11]  The glide calculator shows that 3,200 feet is  needed to accomplish the glide. Add 1,500 feet above ground  to allow time to set up for an off-field landing if necessary,  to make the total needed 4,700 feet. The present height is  only 3,800 feet, not high enough to accomplish the 12-mile  glide, but still high enough to start along course. Head out  adjusting the speed based on the MacCready ring or other  speed director. After two miles with no lift, altitude is almost  3,300 feet, still not high enough to glide the remaining 10  miles, but high enough to turn back to the last landing site.  After almost 4 miles, a 4-knot thermal is encountered at about  2,700 feet and provides for a climb to 4,300 feet.  Determining winds aloft while en route can be difficult. Often  an estimate is the best that can be achieved. A first estimate  is obtained from winds aloft forecasts provided by the AFSS.  Once aloft, estimate windspeed and direction from the track  of cumulus shadows over the ground, keeping in mind that  the winds at cloud level are often different than those at  lower levels. On cloudless days, obtain an estimate of wind  by noting drift while thermaling. If the estimate was for a  headwind of 10 knots but more height is lost on glides than  the glide calculator indicates, the headwind estimate may be  too low and will need to be adjusted. When flying with GPS,  determine windspeed from TAS by simple subtraction. Some  flight computers automatically calculate the winds aloft while  other GPS systems estimate winds by calculating the drift  after several thermal turns. communication frequency and listening to traffic in the traffic  pattern. As progress is made along each leg of the triangle,  frequently cross check the altitude needed to return to the  home airport and abandon the course if needed. Setting a  minimum altitude of 1,500 feet or 2,000 feet AGL to arrive  back at the home site adds a margin of safety. Every landing  after a soaring flight should be an accuracy landing. Cross-Country Techniques 11-9 Figure 11-10.  Examples of practice cross-country courses. 5 NM 5 NM 5 NM 4 NM 7 NM 8 NM 5 NM 10 NM 10 NM 10 NM