This section is not meant to be a treatise on wave soaring but a few general hints which may assist people who do not have much experience of this type of lift.
Working wave lift is much the same technique as working hill lift as the lift (and sink) is found in an elongated area lying across the wind and which stays fixed in one location – some of the time! It can be present at low, medium and high levels or all three at the same time. Cloud may or may not be present.
The lift itself is generally silky smooth, varying from zero sink to 15–20 knots (up and down!) and it may be that no control movements are necessary for minutes at a time. Before the lift is contacted however very turbulent air can be encountered in passing through areas of rotor. The lift is usually found up wind of this rough air and the technique thereafter is to use the band of lift in a very similar way to working hill lift
Wave flying is often done in wind speeds >30knots and at operating heights around 5 – 10,000 feet or greater. This makes it almost impossible to judge your exact location by eye and furthermore the ground track of the glider can be rather surprising so here are a few hints:
The oxygen system is your life support system. It must not only function correctly throughout the flight, but you as the pilot must know its operation and its limitations. You should have your oxygen system set up and ready to use prior to launching.
The use of supplemental oxygen is recommended above 10,000 feet and mandatory above 13,000 feet. Bear in mind that there are considerable variations in tolerance to lack of oxygen so if you have any doubts, go on oxygen sooner. Due to the rapid rate at which you may climb in wave have your oxygen mask/cannula within easy reach so that it can be donned quickly. Consider using oxygen while descending to low levels or even landing especially if you are cold and tired after a long flight. The effects of a lack of oxygen are pernicious; be constantly alert to your own well-being.
Watch for signs of the wave gaps filling in and creating a solid layer of cloud beneath you through which you may have to make a long descent on instruments. This itself causes no real problems provided you know what height cloud base is and what your position is and you are competent at cloud flying (cloud flying rating!), though be alert to airframe icing. We have some fairly high mountains just to the North of us and they can easily become cloud covered! If the wave system collapses the general environmental change could lead to a significant lowering of the cloudbase. If you have a radio, call other gliders or Portmoak Base and ask what the cloudbase is.
Navigation above cloud has been greatly simplified with the introduction of GPS moving maps and all pilots wishing to make wave flights must use one. Remember though, your GPS moving map should never be fully relied on to get you home; battery power in cold conditions being a particular concern. You should back it up with basic navigation skills at all times using your aeronautical chart.
If you have lost contact with the ground and are forced to descend through cloud you have two options:
The Benign Spiral Mode is a technique where, once properly trimmed, the glider is allowed to enter a gentle spiral of its own volition and left there without the pilot touching the controls until clear of cloud. Obviously the glider will drift downwind, possibly at quite a rate, so be aware of entering airspace laterally.
To enter a Benign Spiral, do the following while still in VMC if possible:
It is recommended that this method of descent is practised a few times in clear air before needing to use it in cloud!
Entering cloud can be very dangerous unless you are competent at cloud flying. Avoidance is the best strategy so open the airbrakes and descend as soon as there are any indications of the cloud gaps closing below you.