曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
of situational awareness and understands the horizontal component, and therefore begins the approach with many more options available. In this example, if the pilot is tending more towards the road, he or she can “extend” the approach to remain in more favorable winds, and then continue the descent when the turn is more advantageous to the landing.
The vertical component of the landing profile is represented in Figure 8-3. This may be referred to as a “natural” descent profile. For example, the pilot may see a large field in the distance ahead and elect to initiate a shallow or low profile approach. The pilot would let the balloon cool naturally until it reached the point depicted as Point A in Figure 8-3. A normal descent rate at that point would project the balloon out on a line tangent with the descent curve at that moment. From that point, the pilot must maintain that line much like the control necessary for contour flying.
If, however, the winds are somewhat lighter or the landing site is tight, conducting the approach from Point B, Figure 8-3 might be more appropriate. Again, the pilot should wait until the tangent of the descent curve aligns with the targeted
8-4
A
BC
Figure 8-3. Vertical profile for landing.
landing site. At that point, the pilot should make a half burn and the balloon will follow the desired path.
As a final illustration, steep descents, as previously discussed in Chapter 7, are usually initiated and controlled from the point or area depicted as C in Figure 8-3. The pilot must take both planes of movement, the horizontal as well as the vertical, into consideration when making the approach.
Again, the balloon pilot must visualize the landing by imagining the path through the air and across the ground. Constant scanning in all directions while on the desired approach is imperative. Target fixation can cause a pilot to miss potentially dangerous objects or situations. Look for obstacles, especially powerlines, near the imagined track. Note surface wind velocity and direction by looking for smoke, dust, flags, moving trees, and anything else that indicates wind direction. Do not be influenced too much by a wind indicator at a distance from the proposed site if there is a good indicator closer.
As an example, imagine flying level at 700 feet above ground level (AGL) and it is time to land. Checking the fuel, there is 30 percent remaining in each of the two 20-gallon tanks. The balloon’s track across the ground is toward the southeast, but a farmer’s tractor is observed making a column of dust that is traveling nearly due east. The dust cloud rises from the ground at about a 45° angle. From this information, it is believed that the balloon turns left as it descends. This means the pilot is looking to the left of the line the balloon now travels. By dropping small tissue balls, the pilot determines that the wind changes about halfway to the ground and continues to turn left about 45°. As an initial plan, visualize the descent being no faster than about 500 feet per minute (fpm) initially and slowing to about 300 fpm about 400 feet AGL where the turn to the left can be expected. Because the balloon loses some lift from the cooling effect of the wind direction change, the rate of descent should be closely monitored during the turn.
With this imagined descent in mind, the pilot searches for an appropriate landing site. The next fallow field to the left of the present track is blocked by tall powerlines. The landing site is rejected as unsuitable. The next field that seems appropriate is an unfenced grain stubble field bordered by dirt roads with a 30-foot high power line turning along the west side to the left and parallel to the balloon’s present track. Under the powerlines is a paved road with a row crop of sugar beets to the right and directly in the balloon’s ground track.
The pilot selects a landing site at the intersection of the two dirt roads at the southeast corner of the field. The planned path would be across the field diagonally giving the greatest distance from the powerlines. Extending the final approach line back over the powerlines and into the sugar beet field, the pilot selects a point where the balloon is likely to begin its surface wind turn. Then, reverse planning from that point, a point should be determined in order to begin the initial descent.
Now, the balloon pilot performs the descent, turn, and landing that is visualized. If all goes as planned, the balloon cools and accelerates to about 500 fpm. The pilot applies some heat to arrest the descent while approaching the imagined turning point over the beets, levels off (or actually climbs a bit) while crossing over the power lines (about 100 feet above), and allows the balloon to cool again while setting up another descent across the stubble field. Due to the seven mile per hour (mph) estimated wind, the pilot allows the basket to touch down about 150 feet away from the dirt road intersection to lose some momentum as the basket bounces and skids over to the road, just as planned.
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
Balloon Flying Handbook(96)
