直升机教员手册 Helicopter Instructor’s Handbook
时间：2014-11-10 08:35来源：FAA 作者：直升机翻译 点击：次
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To view this page ensure that Adobe Flash Player version 9.0.124 or greater is installed. Servo actuators—varies with each helicopter design, but a common hydraulic system will have four servo actuators: one directional, one collective, and two cyclic. Return manifold—fluid leaves the actuators and travels through the return manifold and recycles through the return filter. The fluid then passes through the quick disconnect coupling to the hydraulic. Hydraulic System Failure Explain to the student what the procedures are if a hydraulic system failure occurs. Discuss with the student the difference in control after a hydraulic system failure while at a hover or in forward flight. Hover is difficult because of the tendency of overcontrolling the helicopter and the stiffness of the controls. A run-on landing is a suitable option during a hydraulic system failure. NOTE: Some hydraulic systems operate at pressures exceeding 1,000 pounds per square inch (psi). Students should be cautioned about searching for hydraulic leaks while the system is still under pressure. The system accumulator can have high system pressure for long periods of time after shutdown and if any part of the human body is exposed to such high pressure streams, those streams can act like a needle and puncture the skin injecting the toxic fluid into the body. Stability Augmentation Systems (SAS) The stability augmentation system (SAS) was developed from an earlier method which prevented the cyclic from flopping around, force trim, which would hold the cyclic control only in the position at which it was released. Force trim was a passive system that simply held the cyclic in a position which gave a control force to transitioning airplane pilots who had become accustomed to such control forces. Students should learn that SAS is an active stabilization system that helps the helicopter track the position of the cyclic relative to the horizon. Some systems are designed to use as much as 10% of the total servo travel to control the helicopter. This is achieved automatically without inputs from the pilot; with this type of system installed, the pilot work load is reduced. The helicopter is a bit more stable with SAS installed, and it dampens unwanted helicopter movement during flight and at a hover. Instructors should show the student the SAS actuators, which are mounted on the hydraulic servos and are fed information from gyros that sense the: pitch, roll, and yaw axes of rotation. Important information to relay to the student is that the SAS requires power, both for the stabilization platform and for the actuators. Like any other helicopter system, they are subject to failure and instructors need to discuss emergency actions that may be required if the system were to fail. Autopilot Explain to the student that the more sophisticated SASs have additional features, such as an autopilot. As suggested, the autopilot can perform certain duties as selected by the pilot. Some of the basic systems perform only basic functions, such as heading and altitude. Some of the advanced systems perform certain functions, such as climb/descent rate, navigation capabilities that track to points and some fly instrument approaches to a hover without any additional pilot input. Autopilot is widely used by the United States Coast Guard to assist in search and rescue and to recover the helicopter during adverse weather conditions, as well as in many turbine powered helicopters which allows for single pilot IFR operations NOTE: It is important to refer to the autopilot operating procedures located in the RFM, if autopilot is installed. Environmental Systems (Heating/Cooling) Explain to the student that many smaller helicopters only have doors as part of their environmental systems. Show where the doors will be stored and how to properly store all loose equipment and seat belts. Once the doors are removed, stress the importance of a clean and secure cabin. Many accidents have occurred when objects have blown from the cabin and damaged both the mainrotor and tailrotor. Pilots have lost maps, charts, sunglasses, cushions, jackets etc. from the cabin or cockpit. Flapping seatbelts can also cause unnecessary damage to the side of the helicopter in flight. Show how the ram air functions and the location of any levers that are used to control ram air. If installed, show the location and controls of the air conditioning unit. The pilot should be well versed in the operation and restriction of use of the air conditioning unit. Many units are restricted from use during takeoffs and landing due to power demands. Ensure the student refers to the RFM for the proper operating procedures. Discuss the cabin heating system with the student and locate the heater ducts and switches that control them. Piston-powered helicopters use a heat exchanger shroud around the exhaust manifold, and turbine-powered helicopters use a bleed air system for cabin heat. Any other systems that use forced air or heat should be discussed at this time, such as defog blowers for the main windscreen. Anti-Icing Systems First and foremost, students need to understand that anti- icing is the process of protecting against the formation of frozen contaminant, snow, ice, or slush on a surface. Icing can occur as the helicopter sits over night or during flight. In either case, icing becomes a hazard and if not attended to can be disastrous. Include the following topics when discussing anti-icing systems: engine anti-ice, carburetor icing, preflight, and deicing. Engine Anti-Ice Discuss with the student the importance of using the engine anti-ice system if certain conditions are encountered and the loss of performance when the system is in use. The instructor should be able to explain why the engine anti-ice decreases power so much. The following information should be explained to the student: 1. Engine anti-ice uses bleed air to heat inlet. 2. The bleed air exits the inlet area into the inflow which decreases the air density due to the high temperature air. 3. Although the anti-ice may keep the engine operating, everything else is still subject to icing. Real icing conditions dictate an immediate exit from those conditions. |
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