航空電子設(shè)備-自動油門

1、 Civil Aviation Flight University of China Auto Throttle 自動油門Auto Throttle (A/T) Civil Aviation Flight University of China A typical A/T system provides automatic thrust control from the start of take-off through climb, cruise descent, approach and go-around or landing. The A/T system also ensures t

2、hat the engines operate within the permitted engine limits. The A/T system has a number of operating modes that can be used from brakes release through to landing. Auto Throttle (A/T) Civil Aviation Flight University of China A/T Mode Control PanelFigure 3.15 Civil Aviation Flight University of Chin

3、a A/T Mode Control PanelA/T ARM switch arms autothrottle for engagement. Autothrottle engages when EPR or SPD switch is pushed, and when V NAV, FL CH or GA modes are active.EPR switch engages autothrottle to hold reference EPR displayed on EICAS, subject to maximum speed limits.SPD switch engages au

4、tothrottle to hold speed or Mach indicated in IAS/MACH indicator. It cannot be engaged while in the TO thrust mode. Civil Aviation Flight University of China A/T Mode Control PanelFigure 3.15A/T DISC light indicates autothrottle is disengaged, either due to malfunction, pushing autothrottle disengag

5、e switch, or raising reverse levers to the interlock. Autothrottle disengage switches disengage the autothrottle. Second push turns off A/T DISC light. Civil Aviation Flight University of China Figure 3.16Thrust Mode Control Panel Required EPR (or N1) for the A/T EPR mode would be selected on a sepa

6、rate thrust mode control panel . The available thrust modes are: take-off/go-around (TO/GA) full power; climb power (CLB), plus two values of derated climb power; maximum continuous power (CON); and cruise power (CRZ).Thrust Mode Control Panel Civil Aviation Flight University of China Thrust mode se

7、lect switches select the thrust mode to be used by the thrust management computer for reference EPR limit computation. The active thrust mode and reference EPR are indicated on EICAS. With VNAV engaged, manual selection of GA, CLB, and CON is inhibited. Thrust Mode Control PanelFigure 3.16 Civil Avi

8、ation Flight University of China Climb thrust derate switches select either of two fixed percentage derate values for climb thrust computation. Switch 1 selects approximately 8% derate and switch 2 selects approximately 16%. Thrust Mode Control PanelFigure 3.16 Civil Aviation Flight University of Ch

9、ina TEMP SEL knob selects the assumed temperature for derated take-off thrust. If an assumed temperature is not selected, the computer uses the higher of TAT or flat rated temperature to compute the take-off limit. The knob is active only in the take-off mode.Thrust Mode Control PanelFigure 3.16 Civ

10、il Aviation Flight University of China Autothrottle Mode Annunciations Autothrottle mode annunciation indicates in green that autothrottle is engaged in the displayed mode. Possible mode annunciations are EPR, SPD, FL CH, GA, IDLE, TEST and THR-HOLD. Possible limit annunciations are FLAP, ALPHA, SPD

11、 LIM. Only one limit mode is displayed at a time.Figure 3.17 Civil Aviation Flight University of China Operation of a Typical Autothrottle System Reduced Thrust Take-off Mode An assumed temperature is selected. The autothrottle is engaged by pressing the EPR switch. The autothrottle will engage in t

12、he TO mode and the throttles will be driven forward until reduced take-off thrust (assumed temperature) is achieved. Below 80 kt groundspeed as sensed by the IRS, the throttles are driven continuously to sustain this EPR. Above 80 kt groundspeed, electrical power to the throttle drive motor(s) is wi

13、thdrawn, and the autothrottle mode changes to THR HOLD. Any adjustment now made by the pilot will not be countered by the autothrottle. After take off, the autothrottle can be re-engaged in an active mode by pressing the EPR button. Civil Aviation Flight University of China Operation of a Typical Au

14、tothrottle System Full Power Take-off Mode When conditions do not permit the use of reduced thrust, or if the pilot decides to use maximum thrust, this take-off mode can be engaged by pressing the TO/GA button. This selection overrides any assumed temperature inputs, and the engine is accelerated to

15、 the limiting EPR for the ambient conditions. THR HOLD mode and re-engagement of an active mode remain the same. Climb Mode The thrust mode control panel offers three values of climb power; (full) climb power, Derate 1 climb power, and Derate 2 climb power, enabling the pilot to select the level of

16、derate most suitable to the conditions of the day. Derate1 is a reduction of about 8%, while Derate 2 reduces climb power by about16%. Civil Aviation Flight University of China Operation of a Typical Autothrottle System Speed Mode This mode is engaged by selecting an appropriate IAS or Mach in the A

17、FDS speed setting window and pressing the speed mode control button. Once set, the A/T will move the power levers as required to maintain the desired speed, within the boundaries of allowed engine limits. Flight Level Change Mode When the FL CH mode is engaged, the autothrottle will set climb power

18、or flight idle as required, depending on whether the selected altitude is above or below the aircraft. Civil Aviation Flight University of China Operation of a Typical Autothrottle System Go-around Mode In most systems the go-around mode is armed as a standard procedure whilst on final approach. GA is armed automatically when flap is selected or on captur