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On an actual cross-country flight, a combination of dolphin flight and classic climb and glide is frequently needed. In a previous example, the two pilots who decided not to stop and circle in the weaker thermals would still benefit from dolphin flight techniques in the lift and sink until stopping to climb in the strong lift. 

## Special Situations 

## Course Deviations 

Diversion on a soaring cross-country flight is the norm rather than the exception. Some soaring days supply fair weather cumulus evenly spaced across all quadrants, and it is still beneficial to deviate toward stronger lift. Deviations of 10° or less add little to the total distance and should be used without hesitation to fly toward better lift. Even deviations up to 30° are well worthwhile if they lead toward better lift and/or avoid suspected sink ahead. The sooner the deviation is started, the less total distance is covered during the deviation. [Figure 11-16] 

Deviations of 45° or even 90° may be needed to avoid poor conditions ahead. An example might be a large cloudless area or a shaded area where cumulus have spread out into stratus clouds. Sometimes deviations in excess of 90° are needed to return to active thermals after venturing into potentially stable air. 

Deviations due to poor weather ahead should be undertaken before the flight becomes unsafe. For instance, if cloud bases are lowering and showers developing, always have the option for a safe, clear landing area before conditions deteriorate too much. Generally, glider pilots will encounter stable air or sinking air which will put them on the ground before VFR conditions disappear. If the sky becomes cloudy, thermaling will cease. Ridge lift might remain but will be in the clouds so either way the glider pilot must get on the ground. It is better to land on your terms rather than be forced down by total lack of lift. Thunderstorms along the course are a special hazard, since storm outflow can affect surface winds for many miles surrounding the storm. Do not count on landing at a site within 10 miles of a strong thunderstorm—sites farther removed are safer. Thunderstorms ahead often warrant large course deviations of up to 180° (i.e., retreat to safety). 

NOTE: Cloud development can and does shade the earth, decreasing the heating, and hence decreasing lift. Be aware of cloud shadowing. 

## Lost Procedures 

Navigation has become far easier with the advent of GPS. Since GPS systems are not 100 percent free from failure, pilots must still be able use the sectional chart and compass for navigation. It is important to have an alternate plan in the event of becoming lost. As discussed earlier, preflight 

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