直升机飞行手册 Helicopter Flying Handbook

时间：2014-11-09 12:30来源：FAA 作者：直升机翻译 点击：次

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Takeoff
A pinnacle takeoff is considered an airspeed over altitude maneuver which can be made from the ground or from a hover. Since pinnacles and ridgelines are generally higher than the immediate surrounding terrain, gaining airspeed on the takeoff is more important than gaining altitude. As airspeed increases, the departure from the pinnacle is more rapid and helicopter time in the “avoid” area of the height/ velocity decreases. [Figure 10-10] In addition to covering unfavorable terrain rapidly, a higher airspeed affords a more favorable glide angle and thus contributes to the chances of reaching a safe area in the event of a forced landing. If a suitable forced landing area is not available, a higher airspeed also permits a more effective flare prior to making an autorotative landing.
determine the angle to use in the final part of an approach.
As a general rule, the greater the winds are, the steeper the
approach needs to be to avoid turbulent air and downdrafts.
Groundspeed during the approach is more difficult to judge because visual references are farther away than during approaches over trees or flat terrain. Pilots must continually perceive the apparent rate of closure by observing the apparent change in size of the landing zone features. Avoid the
Height above ground (feet)
appearance of an increasing rate of closure to the landing site. 200 The apparent rate of closure should be that of a brisk walk. If a crosswind exists, remain clear of down-drafts on the leeward 100 or downwind side of the ridgeline. If the wind velocity makes the crosswind landing hazardous, it may be possible to make
a low, coordinated turn into the wind just prior to terminating 0 the approach. When making an approach to a pinnacle, avoid
Airspeed KIAS (knots)
leeward turbulence and keep the helicopter within reach of a
Figure 10-10. Height/velocity chart.
forced landing area as long as possible.
On takeoff, as the helicopter moves out of ground effect, maintain altitude and accelerate to normal climb airspeed. When normal climb speed is attained, establish a normal climb attitude. Never dive the helicopter down the slope after clearing the pinnacle.
Common Errors
1. Failing to perform, or improper performance of, a high or low reconnaissance.
2. Flying the approach angle too steep or too shallow for the existing conditions.
3. Failing to maintain proper rpm.
4. Failing to consider emergency landing areas.
5. Failing to consider how wind and turbulence could affect the approach and takeoff.
6. Failure to maintain pinnacle elevation after takeoff.
7. Failure to maintain proper approach rate of closure.
8. Failure to achieve climb airspeed in timely manner.
Chapter Summary
This chapter described advanced flight maneuvers such as slope landings, confined area landings, and running takeoffs. The correlation between helicopter power requirements, the environment, and safety were also explained to familiarize the pilot with how the helicopter reacts during different maneuvers. Hazards associated with helicopter flight and certain aerodynamic considerations were also discussed.
Autorotation
In a helicopter, an autorotative descent is a power-off maneuver in which the engine is disengaged from the main rotor system and the rotor blades are driven solely by the upward flow of air through the rotor. [Figure 11-1] In other words, the engine is no longer supplying power to the main rotor.
The most common reason for an autorotation is failure of the engine or drive line, but autorotation may also be performed in the event of a complete tail rotor failure, since there is virtually no torque produced in an autorotation. In both areas, maintenance has often been a contributing factor to the failure. Engine failures are also caused by fuel contamination or exhaustion as well resulting in a forced autorotation.

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