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. Also discuss with the student that during a landing, if there is a headwind present, it may help prevent a settling with power situation from developing. Conversely, if there is a tailwind, settling with power conditions are encountered earlier as the helicopter slows for a landing. A crosswind is much more preferable to a tailwind. The instructor should work with the student to ensure an understanding of the apparent groundspeed versus airspeed factors and differences. If a pilot begins a landing approach with a 10 knot tailwind, at some time in the approach, the helicopter experiences a zero knot airspeed, which means a total loss of translational lift and thrust. In order to maintain the approach angle, more power must be added. If the conditions of less than 10 knots of airspeed, more than 300 feet per minute rate of descent and more than 20 percent power is applied to the rotor system exist, the helicopter is prone to encounter settling with power. Height/Velocity Diagram Ensure the student understands the information in the height/ velocity diagram in the applicable POH/RFM and knows how to fly to avoid those unsafe areas in the height/velocity diagram. [Figure 8-2] Referring to the aerodynamics of autorotation, explain that this chart shows those heights above ground and airspeeds which, in the event of engine or drive train failure, an experienced pilot should be able to make a safe autorotational landing. The instructor must stress that the conditions provided in the chart are ideal conditions with an experienced pilot. The instructor may wish to revisit the aerodynamic theory of autorotation. Specifically, discuss that altitude equates to potential energy; therefore, during autorotational descent the unpowered rotor system maintains kinetic energy as the descending helicopter loses potential energy in the form of altitude. Through the use of turns, flares, and collective control, the pilot can regulate the amount of available kinetic energy within the rotor system. This rotational kinetic energy in the rotor system is used during the deceleration and landing to slow and cushion the landing. If power is lost in situations of higher altitudes [Figure 8-2, area A] and low to no airspeed, such as OGE operations, the helicopter may not be able to maintain enough kinetic energy (rotation of the rotor system) to establish the minimum rate of descent airspeed necessary for a successful landing. Also, in flight profiles with higher airspeed [Figure 8-2, area B] and extremely low altitudes, engine failure can cause loss of altitude that will not allow time to take appropriate action to establish an autorotational profile. An effective demonstration of this phenomenon is to have the student note the amount of altitude lost during a high-altitude entry into an autorotational profile and then relate this loss to what would happen in the same situation at low altitudes. It is important to stress that reaction time and immediate response are critical for an experienced pilot to land the helicopter safely. Avoiding flight profiles in the shaded areas of the height/velocity diagram is not always possible. Some jobs require flight maneuvers or tasks with prolonged OGE operations, such as utility/power line flight, aerial photography, logging and other occupations. Have the student think through scenarios in which potential emergencies occur in these profiles. Discuss possible response options the student may have available in these scenarios. As instructors, we should be familiar with primacy; what is first learned is often the first to be retained and practiced. Take time to discuss proper takeoff and landing profiles that minimize unnecessary exposure to these shaded areas of the height/velocity diagram. These techniques may include flying higher into the wind and minimizing excessive aircraft loading. The student must consistently demonstrate these maneuvers during each flight. Performance Planning To make the discussion of performance planning relevant to the student, develop a series of exercises that are scenario based and require use of performance graphs from the POH/ RFM. Each scenario based lesson plan must have a targeted learning point. Different scenarios can demonstrate the effect of each environmental factor (Atmospheric Pressure, Altitude, Temperature and Moisture) affecting density altitude. Figure provides a scenario in which the student pilot departs a near sea level location and arrives at a substantially higher elevation. This scenario demonstrates the impact of a greater density altitude as well as the increased IGE and OGE power requirement to operate at that high altitude. Discuss with the student scenarios in which OGE power may not be available and the related consequences. Discuss aircraft system or component limitations, such as torque versus altitude-induced limitations or reductions in VNE airspeeds commonly found at higher elevations. At the arrival location, ensure the student accurately prepares departure performance planning with added fuel to return to the initial departure location (plus required reserve fuel). When possible, the scenarios should use high gross weight values that best support the learning objective. If applicable, combine the effects of external loads at higher altitudes, temperatures and wind velocities. Use scenarios that provide significantly higher IGE/OGE power requirements to demonstrate helicopter capabilities or limitations and to determine go/no-go decisions based on the charted values. Instructor Tips . Take every opportunity to advance the student’s awareness of environmental conditions. Accurate and thorough performance planning are essential to safe and successful flight operations. . Require the student to complete performance planning prior to each training flight. This instills the habit and highlights the importance of performance planning. . The student must use the appropriate POH/RFM for the helicopter being flown for all performance planning. |
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