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WINDSHIELD DEFOGGING
Although the windshield defogging system is not classed as an ancillary control, a phase of its operation is included in this exercise.
The windshield of a helicopter should at all times be kept clear and free of anything that will interfere with forward visibility, not only for control purposes, but also to see outside obstructions and other air traffic clearly. Under no circumstances attempt a takeoff with a fogged or partially fogged windshield. The windshield defogging system will generally keep the windshield clear of interior fogging when the helicopter is in flight. However, while hovering or waiting for takeoff, windshield fogging may occur. On these occasions, opening the vents or windows to improve interior air circulation may control fogging.
ENGINE ANTI-ICING
Most light turbine helicopters are equipped with an engine anti-icing system operated by engine bleed air. This system is controlled by an electrically operated valve, and directs hot bleed air to the intake of the compressor, to prevent ice accumulation on the front frame. This system does not have a de-ice capability and should be activated whenever the temperature is 4 degrees Celsius or less in visible moisture to prevent ice accumulation. Details regarding the correct operation of the system used on your particular helicopter will be found in the helicopter flight manual.
NOTE: Light helicopters are not certified for flight into known or forecast icing conditions.
HYDRAULIC SYSTEM
All medium and heavy helicopters and some light helicopters are equipped with hydraulically assisted flight controls. If the type you are training on is so equipped you will be taught how the system operates and emergency procedures associated with a failure. Most medium and light helicopters can be flown without hydraulic assistance but the controls become quite heavy. Heavy helicopters cannot be flown without hydraulic assistance so they are equipped with multiple systems for backup.
ROTOR BRAKE
Some light helicopters are equipped with a hydraulically operated rotor brake, which can be used by the pilot to rapidly decelerate the rotor after engine shutdown. The hydraulic system for the rotor brake is most often self-contained and not a part of the helicopter flight control hydraulic system. This type of system will have rotor RPM limits above or below which you should not apply the brake due to the possibility of damaging the drive train. This information will be found in the helicopter flight manual and is normally placarded in the aircraft and clearly marked on the rotor tachometer.
HEATER
Most light helicopters have a cabin heater, which may be one of several different types, including: engine bleed air, muff or “Casey”, and combustion heaters. Your instructor will demonstrate the operation of the type of heater that is installed in your helicopter and brief you on the safety precautions regarding its use. Once again the helicopter flight manual will contain information on the operation of the heater.
EXERCISE 4 - AIRSPEED AND POWER CHANGES STRAIGHT AND LEVEL FLIGHT
Now that you have seen the effects of each control movement, you can begin to control airspeed and power and make precise changes. You can also begin to co-ordinate control movements in order to maintain balanced flight as airspeed and power changes take place, with all control movements concentrated on developing a smooth and accurate touch.
During this exercise you will make attitude changes looking at the horizon and then confirm the changes with the instruments. Avoid looking at the instruments for a long period of time.
CHANGING AIRSPEED
Your instructor will demonstrate changing airspeed by moving the cyclic and will point out to you both the resulting visual and instrument indications. To reduce speed from cruise to a specific airspeed for example, from 80 mph to 60 mph, ease the cyclic aft to select the attitude, hold the attitude, and finally adjust the attitude for accuracy. You will notice that the speed begins to decrease and the altitude increase. Concentrate for the moment on the airspeed, anticipate before you reach 60 mph, and adjust the cyclic to maintain that airspeed. Throughout these manoeuvres ensure that you maintain co-ordinated flight by preventing yaw with the tail rotor pedals.
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直升机飞行训练手册 HELICOPTER FLIGHT TRAINING MANUAL(11)
