直升機(jī)教員手冊 Helicopter Instructor’s Handbook
時間：2014-11-10 08:35來源：FAA 作者：直升機(jī)翻譯 點擊：次
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To view this page ensure that Adobe Flash Player version 9.0.124 or greater is installed. During the descent, instruct the student to adjust collective pitch control as necessary to maintain rotor rpm. Emphasize avoiding large collective pitch increases because they result in a rapid decay of rotor rpm. Demonstrate how aft cyclic movements cause a temporary increase in rotor rpm. At approximately 40–100 feet above the surface, or at the altitude recommended by the manufacturer, demonstrate the deceleration with aft cyclic control. Explain how the deceleration is used to both reduce forward airspeed and decrease the rate of descent. Point out that the cyclic control is not moved rearward so abruptly as to cause the helicopter to climb. Show how the helicopter is placed in the landing attitude at approximately 8–15 feet, or the altitude recommended by the manufacturer. Explain that extreme caution should be used to avoid an excessive nose high and tail low attitude below 10 feet. Demonstrate the application of collective pitch, as necessary, to slow the descent and cushion the landing. Explain that additional antitorque pedal is required to maintain heading as collective pitch is raised due to the reduction in rotor rpm and the resulting reduced effect of the tail rotor. Emphasize touching down in a level flight attitude. NOTE: A power recovery can be made during training in lieu of a full touchdown landing. (Refer to the section on power recoveries for the correct technique.) After touchdown, and after the helicopter has come to a complete stop, lower the collective pitch to the full-down position. Discuss the hazards of using the cyclic or collective to slow the helicopter’s ground run. NOTE: Numerous tail boom strikes have occurred due to improper collective pitch response upon ground contact and completion of the maneuver. Particular attention must be emphasized as to the proper rate and timing of lowering collective to avoid potential damage to aircraft components. Emphasize the minimum requirements for rotor rpm, airspeed, and trim conditions throughout the maneuver. If the instructor or the student feels uncomfortable with the autorotation, do not hesitate to initiate a go-around. The instructor is responsible and should terminate the maneuver anytime the parameters vary from normal, or if either pilot determines something is not right. These are common comments that are submitted on accident or incident reports. Therefore, the instructor should be especially aware of these occurrences and err on the side of caution by making power recoveries or go-arounds if any doubts exist. The instructor’s primary duty is to ensure the student has safe flights and does not get into trouble. The instructor should highlight the student’s understanding of the wind’s effects as related to airspeed versus ground speed, and the amount of flare necessary to slow for the landing. The instructor should help the student to cope with the increased airflow through the rotor system in the flare and how to control rpm, both increasing and decreasing. The importance of landing gear alignment cannot be overemphasized during actually touchdowns. If the helicopter is kept in trim, the rate of descent will be the minimum rate. Out of trim conditions increase the rates of descent considerably. Usually, it is useful to demonstrate how much out-of-trim conditions can increase the rate of descent. Although not usually needed or desired, a steeper descent angle to enable an emergency landing in a very close-in landing area could be useful, but only if the student is trained how to recover and arrest that increased rate of descent. Autorotations With Turns, With Instructional Points When autorotations are first introduced, they are usually conducted straight ahead and into the wind. Discuss with the student that a turn, or a series of turns, may be necessary during an autorotation to land into the wind or avoid obstacles. Emphasize that the turn should be completed as soon as possible during the descent so that the remainder of the autorotation is the same as a straight-in autorotation. Ensure the student is aware that, during the turn, the rotor rpm must be closely monitored as it has a tendency to build during the turn. Airspeed, on the other hand, may be unreliable until the turn is completed. The importance of maintaining the helicopter in trim cannot be overemphasized. Instruct the student to adjust the collective as necessary in the turn to maintain the rotor rpm in the green arc. If the collective pitch was increased to control the rpm, it may need to be lowered on rollout to prevent a decay in rpm. During training, the turn should be completed and the helicopter in position to land in the intended touchdown area prior to passing through 100 feet above ground level (AGL). Initiate an immediate power recovery if the helicopter is not aligned with the touchdown point or if the rotor rpm and/or airspeed are not within proper limits. Power Recovery From Practice Autorotation, With Instructional Points From an instructor’s point of view, it must be remembered that a power recovery, if applied too late or too rapidly, can result in hard landings that sever tail rotor drives (resulting from loss of yaw control), overboosting of turbocharged engines, overtemping and/or overtorques of turbine engines. To avoid this from occurring, think through power application using an early, smooth, and measured response. Do not wait until the helicopter is on the verge of being unrecoverable to initiate the power recovery. Upon initial training, explain to the student that a power recovery is used to terminate practice autorotations or simulated engine failures at a point prior to actual touchdown. The power recovery itself is not an emergency procedure. In the event of an emergency that requires autorotation, the student must be prepared to complete the autoroation to touchdown. Emphasize the importance of the throttle detent to avoid inadvertent shutdown. This may occur by unintentionally closing the throttle to the off position. As the instructor, it is your responsibility to verify the power control detent is in the proper position when manipulating the throttle in flight. |
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