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the glider and the ridge. In that case, either turn back in the other direction (away from the ridge) if traffic permits or fly upwind away from the ridge and rejoin the slope lift as traffic allows. If using a radio, try to contact the glider by the completion number and then coordinate the passing. When soaring outside of the United States, be aware that this rule may differ. 

The glider with its right side to the ridge has the right of way. [Figure 10-22D] Title 14 of the Code of Federal Regulations (14 CFR) requires both aircraft approaching head-on to give way to the right. A glider with the ridge to the right may not have room to move in that direction. The glider with its left side to the ridge should give way. Additionally, when overtaking a slower glider along the ridge, always pass on the ridge side. If the overtaking glider encounters sink, turbulence, etc., it must maneuver away from the ridge. This is acceptable. When piloting the glider with its right side to the ridge, ensure the approaching glider sees you and is 

yielding in plenty of time. In general, gliders approaching head-on are difficult to see; therefore, extra vigilance is needed to avoid collisions while slope soaring. The use of a radio during ridge soaring is recommended. Pilots must be familiar with 14 CFR part 91, section 91.113, Right-of-way rules: Except water operations, and section 91.111, Operating near other aircraft. 

## Bowls and Spurs 

If the wind is at an angle to the ridge, bowls or spurs (i.e., recessed or protruding rock formations) extending from the main ridge can create better lift on the upwind side and sink on the downwind side. If at or near the height of the ridge, it may be necessary to detour around the spur to avoid the sink, then drift back into the bowl to take advantage of the better lift. After passing such a spur, do not make abrupt turns toward the ridge. Always consider what the general flow of traffic is doing. If soaring hundreds of feet above a spur, it may be possible to fly over it and increase speed in any sink. This requires caution since a thermal in the upwind bowl, or even an imperceptible increase in the wind, can cause greater than anticipated sink on the downwind side. Always have an escape route or, if in any doubt, detour around. [Figure 10-23] 

## Slope Lift 

It is not uncommon for thermals to exist with slope lift. Indeed, slope soaring can often be used as a “save” when thermals have temporarily shut down. Working thermals from slope lift requires special techniques. When a thermal is encountered along the ridge, a series of S-turns can be made into the wind. Drift back to the thermal after each turn if needed and, of course, never continue the turn to the point that 

