Karabiners are used in hang gliding to attach the harness (that holds the pilot) to the hang glider. This connection needs to be detachable so the pilot can disconnect from the glider after landing safely and ideally, with the pilot able to do this with one hand. Most pilots fly with one karabiner and while this can be considered as a single point of failure, the karabiners used are incredibly strong! Steel karabiners are strongly recommended for hang gliding although some pilots may use a secondary aluminium karabiner as a back-up. I personally fly with a single steel karabiner specifically designed for hang gliding which I replace every 5 years. I prefer to fly with one karabiner as there have been occasions where I have top landed on a windy UK hill-top and need to disconnect from the glider quickly. Faffing around with two karabiners with one hand while trying to hold the glider down with the other is, well, tricky!
A karabiners strength differs with its orientation and if it is open or closed. Typically, karabiners are strongest when orientated vertically with their gates closed, referred to as the major axis of the karabiner. This is the configuration to be used for hang gliding. Karabiners can also be loaded across their minor axis (horizontally), but this is weaker than the major. The maximum safe load of a karabiner across both axes is normally etched on the karabiner and is specified in kN. Needless to say, it’s important to load the karabiner across the major axis and ensure that the gate is securely closed.
Maintaining Load Across the Major Axis
As we prepare to launch our gliders there is no tension in the hang straps and the karabiner is free to slip move around them. Sometimes, this can result in karabiners rotating with the hang-straps settling across the minor axis of the karabiner. When the hang straps tension, the karabiners may remain in this orientation. There is an infamous picture in my local hang-gliding club (see below) where this very situation happened and was photographed when the pilot came in to top land.
To avoid the karabiner rotating into this position, I’ve utilised a solution using off-cuts of an old bike innertube to form rubber bands which secure the hang-straps from the harness to the karabiner (see images below). I do change these rubber bands regularly as they will perish with time.