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or 90,000 cubic foot envelope) at 5,000 feet, the pilot may be required to make a standard burn every 15 to 20 seconds to keep the balloon climbing at 500 feet per minute (fpm). At sea level, the same rate may require burning only every 30 to 40 seconds. Burn rates cannot be predicted in advance, but practice provides a basis to begin with and experimentation finds the correct burn rate for a particular day’s ambient temperature, altitude, envelope size, and balloon weight. 

Another skill to develop in ascents is knowing when to stop burning so the balloon will slow and level at the chosen altitude. The transition from a climbing mode to level flight involves estimating the momentum and coasting up to the desired or assigned altitude. One methodology is illustrated in Figure 7-4 . During this flight, the pilot has decided to leave his current altitude (A) and climb to another (C). While climbing, the pilot adjusts burn times to be at a 100 fpm rate of climb by the time he or she is at a point 100 feet below the desired altitude (B). Under most circumstances, the balloon “coasts” the additional 100 feet and rounds out, or resumes level flight, at the desired altitude. It may be necessary to use the vent for a short time to stop the ascent with caution not to vent excessively, thereby causing the balloon to go 

into a descent. The balloon pilot must remember that each manufacturer has a specific interval that the vent can be opened while in flight. Should that interval be exceeded, it can have a disastrous result. With practice and application, the pilot can learn this skill without the use of the vent, not only conserving fuel, but also flying a much more controlled flight. 

Generally, to achieve a smooth transition to the new altitude, the rate of ascent should not exceed the distance to the new altitude. For example, if the balloon pilot is 500 feet below the desired new altitude, the rate of climb should not exceed 500 fpm. When the pilot is 300 feet below the desired altitude, the rate of climb should not exceed 300 fpm. An ascent of 200 to 300 fpm is slow enough to detect wind changes at different altitudes, which is helpful in maneuvering. Above 500 fpm, it is possible to fly through small, narrow wind bands or wind with very small direction changes without noticing. It is a good idea to launch and climb at a slow speed (100 to 200 fpm) to make an early decision regarding which direction to fly. 

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