Circling Etiquette: Rules of Thermalling

One of the crucial skills in gliding is naturally to be able to thermal in rising columns of lift. This allows us to extend our flights by tapping into the energy of Mother Nature. However, as we know, thermals often attract multiple gliders, creating crowded and complex situations in the sky. To ensure safety and efficiency, it’s essential for us all to establish some sort of thermal etiquette. Observing these best practices helps prevent mid-air collisions, reduces conflicts, and allows all pilots to maximise the use of available lift.

Joining a Thermal

When approaching a thermal occupied by other gliders, pilots should enter the thermal in the same direction as the gliders already circling – I’d like to think this is pretty obvious. However, people still join in the opposite direction. Always respect the pilot who is established in the lift.  If you think the lift is better elsewhere, lead them back by opening the turn and showing them the way. This practice minimises the risk of conflict and maintains the group's harmony. Pilots should avoid cutting across the circle or entering at an angle that could disrupt the established flow. There’s nothing worse than when someone intentionally cuts in front, trying to gain an advantage, only to show their belly to the other and hope you don’t hear a bang! Before joining, it is important to assess the thermal’s situation, including the altitude and position of other gliders, and then enter in a predictable manner.

The recommended technique for entering a thermal is to fly parallel to the established circling direction, gradually merging into the turn while maintaining a safe distance from the other gliders. This approach allows the joining glider to smoothly integrate into the thermal without causing disruptions or startling other pilots.

Spacing and Separation

Maintaining adequate spacing between gliders in a thermal is critical for safety. Pilots should aim to keep a horizontal separation of at least 50 to 100 meters from other gliders. This spacing allows for safe manoeuvring and reduces the risk of collision if one glider makes an abrupt move. Always remain predictable.

Vertical separation is also vital. Pilots should avoid climbing directly above or below another glider, as this creates a blind spot for both pilots and increases the risk of collision. In places like Australia and the USA, we often have big shears, meaning we could drop without warning onto the other pilot. It doesn’t matter how in control you feel; it can happen to you, too.

Exiting a Thermal

When we decide to leave a thermal, it’s important to exit in a predictable way that does not disrupt the other gliders. The recommended practice is to roll out of the turn gradually, flying straight until clear of the thermal. We should always avoid sudden or unpredictable manoeuvres that could surprise or endanger others.

Before exiting, it is crucial to check the surrounding airspace, ensuring no gliders in the immediate vicinity could be affected by the departure. Signaling the intention to exit via a brief radio call can further enhance safety, particularly in crowded thermals.

Respect and Cooperation

Ultimately, thermal etiquette is about respect and cooperation among pilots. Sharing thermals requires an understanding that all pilots have the same goal: to stay aloft and make the most of the available lift. By observing proper etiquette, pilots contribute to a safer, more enjoyable, soaring experience for everyone involved.

In competitive soaring, where tensions can be high, it’s especially important to remember that good thermal etiquette benefits individuals and promotes fairness and sportsmanship. When all pilots follow these unwritten rules, the gliding community fosters a culture of mutual respect and camaraderie.

Enjoy the journey

Banner photo by Sean Franke

 Adam Woolley was born into the gliding world, being the 3rd generation in his family. Going solo at 15, his thirst for efficiency in soaring flight & quest for a world championship title to his name has never wavered. One big passion is sharing his experiences & joy with other glider pilots all around the world. Adam is an airline pilot in Japan on the B767 & spends his off time chasing summer around the globe. He has now won 7 national Championships & represented Australia at 5 WGC's & 1 EGC.