Figure 21-3: Obstacle
The handling of the helicopter should be with small, smooth control movements, as this exercise requires a high degree of coordination and accuracy.
EXERCISE 22 - LOW LEVEL OPERATIONS
The helicopter is a very versatile machine. Because of this, it is called upon to do many varied tasks. More and more uses are being found, and as the number of tasks increases, the number involving low level operations increases. The following examples are all flown low level: pipeline, hydro-line, beaver, moose and deer survey. There are numerous other jobs, most are of the reconnaissance variety and all are very demanding because of proximity of the ground and the dangers associated with flying close to the ground.
Considerations
A. Navigation. As you have no doubt discovered in practising cross-country techniques, the lower you fly, the harder it is to map read because of the reduced area visible and the shorter time available for identifying landmarks. To try and navigate a straight line is virtually impossible because of hills or obstacles on your track.
1. Wires: While flying low level your lookout cannot be relaxed for more than an instant, as many of these lines are extremely difficult to see, especially across valleys and in differing light conditions.
Figure 22-1: Low Level Operations-Wires
If you are about to fly low level with someone else on board brief him or her to say “Wires” as soon as they are seen. The pilot-in-command should reply either “Contact” or “No Contact” to confirm the sighting. Similarly, the pilot should comply with the above rule.
Figure 22-2: Low Level Operations-Wires
Wire lines should be crossed at an angle of 45 degrees to give the pilot a choice of turning away from the line or going over the line in case of emergency.
2. Minimum altitudes and distances: Built-up areas and livestock are to be avoided when flying low level. In most cases, flying over these sensitive areas are illegal and dangerous.
Figure 22-3: Low Level Operations-Houses and livestock
3. Low-level flight over the trees: they give little or no choice for you to make an emergency landing. If there are clear areas, try to choose the best flight path with regard to your route
Figure 22-4: Low Level Operations-Trees
4. High ground: Rising or high ground can also cause you to deviate from your track. Try when flying towards high ground to approach at an angle of less that 90 degrees, turning away should be easier in the event of emergency.
Figure 22-5: Low Level Operations-High Ground
B. High Winds.
1. Groundspeed when flying at lower elevations is much more apparent than at altitude. This could give you the impression, when downwind, of a much higher airspeed. If you then further reduce airspeed it will be almost impossible to turn into wind in case of engine failure. Directional control becomes progressively worse as you reduce airspeed. When operating near to maximum weight and high-density altitudes, always maintain a safe airspeed because of the inherent danger of setting up the conditions for vortex ring.
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：直升机飞行训练手册 HELICOPTER FLIGHT TRAINING MANUAL(45)
