Breeze in the Basket – Balloon Instruction Series
One of the most unique phenomena related to hot air balloon flying is the calm conditions experienced in the open basket while traveling across the sky. Except for the occasional burner noise, it provides a surreal platform from which the earth seems to flow by underneath; that is for the unknowing passenger. For the balloon pilot, it means that the aircraft is situated inside of a traveling air mass at least as tall as the balloon itself. What is going on if there is suddenly a breeze in the basket? Can any information be accurately derived from such a breeze? The answer to this question depends on many factors. We will explore the various scenarios and what they mean below.
One of the most obvious balloon basket breezes is the one that occurs just after hot air inflation or a stand up landing. This wind is very significant as it tells you the general direction you are going to go at liftoff and at what speed you are likely to travel as the ground crew weighs you off (hopefully). At deflation, its direction is equally important as it gives you a good idea which way the balloon is going to fall when deflating, regardless of the crown line briefing instructions. It’s very important to become sensitized to these surface winds as they will minimize surprises and resulting damage to the hot air balloon. My instructions to students at takeoff are as follows.
Look upward as you heat the balloon towards equilibrium. At some point, take a short break and look around 360 degrees for potential obstacles. Notice your crew’s hand pressure on the basket or tie off line tension. Continue uniform heating of the balloon envelope and stop looking up when the envelope has stabilized and doesn’t seem to be oscillating. You should refrain from looking up again unless there is a sudden breeze across the basket that might realign the balloon envelope. If the direction of travel is evident by the basket breeze, focus on the top of the highest obstacle within 60 degrees or so of your expected path. Don’t lose focus on that point for any reason other than to look at crew hands or deal with tie off rope for a second. At liftoff, you must be focused on that point. A split second after liftoff, you will know your trajectory and speed if you have continued to focus on that spot. You can then move your focus to a more appropriate spot in line with your actual flight path and safely fly out. If you are focused on an obstacle top at liftoff, you will instantaneously realize your relative flight path and can adjust quickly if necessary. If you are just looking “out”, you will be a second or so behind which may make the difference if an obstacle jumps into your path.
After the balloon leaves the ground and gains some altitude, let’s say you feel a slight breeze on you right cheek. Does this mean the balloon is turning its direction of travel? Can you tell which way? The answer is maybe. Breezes encountered during an ascent are not always as “clean” (uninterrupted) as those found on the descent. At higher rates of ascent, the balloon often distorts a little to become more aerodynamic and a slipstream occurs along one side (random). This breeze produces small gusts in the balloon basket that have no relevance to ground track direction. On the other hand, if a significant breeze from one direction is felt for more than a few seconds during an ascent of 300fpm or less, there is usually information that can be gleaned. Since the ascent air is not always clean at the balloon basket level, it is always prudent to verify the perceived information by simultaneously ground tracking visually as the ascent through the wind (shear) evolves. The anticipated new direction of travel in the aforementioned scenario is towards the direction of the balloon basket breeze or into the wind. If you perform some focused ground tracking in anticipation of the new direction during the ascent through the shear, it will be confirmed quickly and you can use the information immediately as needed. The reason that the anticipated direction is into the perceived wind is that the top of the balloon is being incrementally driven by a different wind as you as ascend. As more of the balloon envelope becomes affected by the upper wind, it literally drags the basket across the “old” or lower wind, making it appear that the balloon basket is going into the wind. With visual confirmation, this is a reliable trigger and source of navigational information. One other note, this transition from one wind direction to another during an ascent can often be called a wind shear rather than just a “turn”. The term “wind shear” in a hot air balloon tends to be used when the wind change or turn is abrupt over a small vertical distance.
The most consistent and useful wind indicators while airborne are the basket breezes felt on a slow to modest descent. They are usually packed with immediate, accurate information if you know how to read them. While on a modest descent (50-300 fpm), the horizontal wind you feel on your legs, face, hands etc is the relative direction the balloon will be going when you put the bulk of the envelope at the level you felt the breeze (50-60 feet below). This not only allows you to forecast what direction change you are about to take but also gives you an opportunity level quickly and not get any turn at all or choose how much of the turn you want by only descending only part way through it. When dipping behind a tree break for a stand up landing this “breeze” you where the brakes (signaled by the gust in your face at a low level. To use this information to its maximum potential requires precise altitude control. This is the “steering” method that allows competitors to navigate that last 50’ of real estate to the center of the target.
Next time you fly, sensitize yourself to the little breezes and try to make sense of them. The breezes on descent are the most intuitive and useful. With a little practice, you too will be crowding the center of the target