Figure 18-2: Range variations
2. Turning (Fig 18-3):
It is also possible to shorten the range of an autorotation by turning the helicopter. When using turns to reduce the range, bear in mind that the increased disc loading can cause a rapid increase in the RRPM. Monitor the RRPM to ensure that the limits are not exceeded; it may also be necessary to raise the collective slightly to prevent overspeeding the rotor, but reduce it again as soon as possible to conserve RRPM for the landing.
Figure 18-3: Shorten the range by turning
In addition to shortening the range of an autorotation, turning will greatly increase the rate of descent. Consider this fact when judging the distance to the desired touchdown spot, as this will determine what type of manoeuvre will allow safely reaching that spot. Figures 18-4, 18-5 and 18-6 represent different examples of turning autorotations.
Rates of descent in tight-turning autorotations can build up to more than 2500 feet per minute in some types of helicopters.
Figure 18-4: the 90-degree turning autorotation
Figure 18-6: the 180-degree turning autorotation
Figure 18-5: the 360-degree turning autorotation
EXERCISE 19 - PRACTICE FORCED APPROACHES
Practice forced approaches, as the name suggests, are the practical application of the autorotation and emergency exercises which your instructor has previously taught you.
During this exercise, you will be shown how to apply these skills to any emergency situations simulated by your instructor. The most common is the surprise engine failure. Your instructor will teach you the actions to be taken should the engine fail. The instructor normally simulated by twisting off the throttle; at that time:
1. enter autorotation by fully lowering the collective, setting the best rate of descent speed with cyclic, and adjust the pedals to control the yaw;
2. select a landing area, obviously the larger and flatter, the better, if possible into the wind;
3. adjust the controls to make the selected area, using the techniques shown in the previous lessons on autorotation to achieve that landing spot (Fig 19-1); and
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