1、Civil Aviation Flight University of China,Autopilot Flight Director Systems,自動駕駛飛行指引系統(tǒng),Autopilot Flight Director Systems (AFDS),Civil Aviation Flight University of China,It is logical to integrate the two systems, the autopilot and the flight director, into a combined autopilot flight director syste

2、m (AFDS) so that certain processing functions can be shared. In a modern system, it is normal for the AFDS to contain a separate FD computer that provides display instructions to the EFIS system, and the same instructions to the autopilot computer, which then converts the signals to appropriate comm

3、ands for the servos.,Autopilot Flight Director Systems (AFDS),AFDS Mode Control Panel,Civil Aviation Flight University of China,AFDS Mode Control Panel,Mode selectors of the Push ON/Push OFF type are located at various positions on the panel. Each selector has a bar light incorporated in the switch

4、face, to indicate the selection. Armed and engaged selections are displayed on the ADI, with armed selections usually shown in white or amber, and engaged modes in green.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Flight Director F/D ON/OFF A flight director (F/D)

5、switch is provided for each pilot. When OFF, FD command bars are withdrawn. When first selected ON, the command bars will be displayed, in the Take-Off mode (TO) if on the ground, or in current values of VS and HDG HOLD if airborne. In the TO mode, the command bars will show wings level and about 81

6、0ANU.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Autopilot AP Engage Switches The autopilot is normally engaged in the Command (CMD) mode. Except during an ILS approach, only one autopilot can be engaged at a time; selection of another autopilot disconnects the fir

7、st. Pushing the second autopilot CMD switch when in the approach mode engages the remaining autopilots at 1,500 ft radio altitude, and arms the autoland functions of runway alignment, flare, landing and rollout.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel,Disengage b

8、ar The DISENGAGE bar at the bottom of the panel must be UP to allow the autopilots to be engaged. By moving the DISENGAGE bar down, all three autopilots are disconnected from the flight control servos. Red (or Yellow) strip is exposed when bar is down.,Figure 3.9,Civil Aviation Flight University of

9、China,When an engaged autopilot is disconnected, usually by pressing the disconnect button on the control column, a warning siren sounds, which can be cancelled by pressing the disconnect button a second time. A fault in an engaged autopilot may also cause a disconnect.,AFDS Mode Control Panel,Figur

10、e 3.10,Figure 3.11,Civil Aviation Flight University of China,A/P DISC light indicates any autopilot is disengaged, either due to malfunction or pushing autopilot disconnect switch. AUTOPILOT light indicates fault in an engaged mode of any autopilot. The light goes off when condition is corrected or

11、affected autopilot is disengaged.,AFDS Mode Control Panel,Figure 3.10,Figure 3.11,Civil Aviation Flight University of China,AFDS Mode Control Panel, Navigation Modes LNAV The LNAV selector, when pushed, will arm the autopilot to capture and then track the lateral navigation track entered into the FM

12、CS. LNAV mode is disengaged by selecting HDG HOLD or HDG SEL mode, or when localizer capture occurs.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Navigation Modes VNAV The FMC of an advanced aircraft is capable of providing vertical navigation by computing a climb or

13、 descent profile to satisfy various requirements, such as maximum rate, optimum profile, maximum speed, or waypoint altitude restrictions. When the FMC has been programmed, and VNAV is selected, the autopilot will follow the required profile, with the engaged autothrottle system controlling the prog

14、rammed speed.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Navigation Modes VNAV VNAV mode can be terminated by any of the following. selecting vertical speed or altitude hold selecting speed or EPR selecting FL CH capturing glideslope reaching altitude in MCP altitu

15、de indicator before reaching FMCS target altitude.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Heading Control Heading Hold The heading hold switch commands the autopilot to maintain present heading. The ADI will show HDG HOLD in the roll mode display. Heading hold

16、is basic roll mode for flight directors and autopilot if no other roll mode is engaged.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel,HDG SEL The HDG SEL selector is a push button located within the bank limit select knob. The HDG SEL knob rotates to set the desired he

17、ading in the digital display, and also positions the heading cursor on the EHSI. Pressing the HDG SEL knob commands the autopilot to turn to and maintain the selected heading. With HDG SEL engaged, the aircraft can be steered by rotating the HDG SEL knob, to adjust the heading. The ADI will show HDG

18、 SEL in the roll mode display.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel,HDG SEL HDG indicator indicates magnetic heading selected with heading select (SEL) knob if localizer has not been captured. It will indicate localizer course after localizer capture. Heading

19、bugs on EHSIs are driven to heading in indicator.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel,Bank Selection BANK LIMIT knob associated with the HDG SEL knob is an outer rotary selector which allows the pilot to limit bank angles available to the autopilot, to improv

20、e passenger comfort. An AUTO position allows the autopilot to decide the amount of bank necessary, and is the most appropriate selection. During instrument approaches, the autopilot will use up to 25 of bank.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Altitude Cont

21、rol ALT Hold The ALT HOLD button commands the autopilot to hold present altitude. If climbing or descending when ALT HOLD is selected, the autopilot will effect a smooth transition and recapture the altitude at which the selection was made. The ADI will show ALT HOLD in the pitch mode display.,Figur

22、e 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel,ALT SEL The altitude select knob is turned to set the desired altitude in the ALT SEL window. The aircraft must be steered towards the desired altitude by using FL CH or a V/S mode. The ADI will show FL CH or V/S in the pitch mo

23、de display, until the altitude is captured, when the pitch mode will change to ALT CAP. ALT indicator indicates altitude selected with altitude knob. It will indicate 10,000 ft when power is first applied.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Vertical Speed C

24、ontrol With Vertical Speed (V/S) selected, the autopilot will maintain the vertical speed set in the V/S window. The value shown in the window is adjusted by rotating the V/S wheel. If the A/T is engaged in SPD mode when V/S is selected, the A/T will maintain the selected IAS. The ADI will show V/S

25、as the active pitch mode. V/S is also the quickest way to initiate climbs or descents.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Vertical Speed Control VERT SPD indicator indicates existing vertical speed when V/S switch is pushed to engage vertical speed mode. It

26、 will indicate vertical speed selected with vertical speed selector when mode is engaged. Range is -8,000 to +6,000 fpm in 100 fpm increments.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Speed Control IAS/MACH Selected autothrottle speed or Mach is set in the IAS/MA

27、CH window. With the A/T SPD mode button selected, and the autothrottle engaged, the system will hold the commanded IAS/Mach. The display is switched from IAS to MACH or back again by alternate presses of the IAS/MACH SEL button to the lower left of the IAS/Mach window. Changes in the displayed digit

28、s is achieved by rotating the two concentric speed control knobs.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Speed Control FL CH Selection of FLIGHT LEVEL CHANGE commands the autopilot to initiate a climb or descent towards the altitude set in the ALT SEL window.,F

29、igure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, Speed Control FL CH The autothrottle will set climb power or flight idle as appropriate, with the autopilot controlling the airspeed in the pitch mode. As the selected altitude is approached, the autopilot mode will change

30、to altitude capture (ALT CAP), and then to ALT HOLD as the autopilot levels the aircraft off, with the autothrottle maintaining the selected speed. The ADI will show FL CH as the active pitch mode, changing to ALT CAP and then ALT HOLD as the aircraft levels off at the selected altitude.,Figure 3.9,

31、Civil Aviation Flight University of China,AFDS Mode Control Panel, ILS Switching LOC (LLZ) Push-button selection of the localizer mode, will arm the autopilot to capture and maintain the tuned localizer track towards the runway. The ADI roll mode will show LOC armed, changing to LOC capture as the c

32、enter line is approached. The missed approach heading can then be set in the HDG SEL window, without pressing the HDG SEL knob, in readiness for a possible missed approach.,Figure 3.9,Civil Aviation Flight University of China,AFDS Mode Control Panel, ILS Switching B CRS The back course mode allows the autopilot to fly a reverse track along a localizer, away from the runway. The appropriate localizer frequency must be tuned, and the aircraft must be steered to enable BCRS capture.,Figure 3.9,Civil Aviation