Flight Director Command Switching Block Diagram
Figure 2

EFFECTIVITY ALL EXCEPT LH O11-030,051-070, 082-099; IB 406-499;
799 Page 3 AZ 212-299; SN 351-399; AT ALL Aug 25/86
34-26-00

CMPTR SEL SW CMPTR SEL SW (P1 PANEL) (P3 PANEL)

M&L NOTE: ALL CONTACTS NOT SHOWN - ONLY TYPICAL

PITCH COMPUTER B
ROLL COMPUTER B MSP: MODE SELECT PANEL PITCH COMPUTER C ROLL COMPUTER C FMA: FLIGHT MODE ANNUNCIATOR PITCH COMPUTER A ROLL COMPUTER A M&L: MONITOR AND LOGIC UNIT
Flight Director Command Switching, Simplified Circuit Diagram Figure 3
EFFECTIVITY ALL EXCEPT: LH 011-030,051-070, 082-099; IB 406-499; AZ 212-299;
799 Page 4
34-26-00

SN 351-399; AT ALLAug 25/86
A  C  B 

COMPUTER SELECT SWITCH (TYPICAL)

ANNUNCIATOR B
Flight Director Select Relay Position/Failure
Indicator Simplified Schematic
Figure 4

EFFECTIVITYALL EXCEPT: AT ALL; AZ 212-299; IB 406-499; LH 011-030,051-070,
799 Page 5 082-099; SN 351-399; Aug 25/86
34-26-00

 (1)  
Sensor input signals processed through the flight director portion of the roll and pitch computers are selected by the captain's and/or first officer's FLT DIR CMPTR select switches. The flight director command and logic signals are applied through the computer select relays to the mode select panel and A/P-F/D monitor and logic unit where they are applied to the captain's and/or first officer's ADI's and flight mode annunciators.

 (2)  
When a FLT DIR CMPTR switch is moved to select a channel other than the one currently selected, a 28-volt dc pulse is applied to the relay coil. Power for the relay coil is applied through the FLT DIR CMPTR switch and the relay operated cam. The relay energizes and its ganged contacts move to the newly selected position. Simultaneously, the operating cam moves until the open position of the cam breaks the circuit at the new position. This action removes power from the relay, and the selected computers are maintained in the circuit until a new channel is selected.

 (3)  
Figure 4 illustrates the three relay position lights over the flight director computer select switch. One light normally illuminates at each selected position. If the relay fails to operate properly, a ground is removed from the selected light.

 EFFECTIVITY
 ALL EXCEPT: LH 011-030,

 051-070, 082-099; IB 406-
 499; AZ 212-299; 
 SN 351-399; AT ALL  09 Page 6  Aug 25/8634-26-00
 FLIGHT DIRECTOR COMMAND SWITCHING - TROUBLE SHOOTING
____________________________________________________

 1.  General
_______
 A.  The following trouble shooting procedures are based on performance of the system operational test and are presented in tree-type format. The test steps (heavy-line boxes) are connected by shaded arrows to show the OK condition path. When all steps in the OK condition path check out, the system is operable.
 B.  When a test step does not check out, follow the NOT OK line to the box containing the trouble symptom. Turn to the procedure indicated and continue to follow a single line by analyzing the results of each test step until the required corrective action is determined. Perform the specified corrective action, then repeat the step at which the failure was encountered.
 C.  All trouble shooting procedures are based on the assumption that wiring is OK and that electrical power is available. If the corrective action in the procedure does not correct the problem, check wiring using the wiring diagram.
 2.  Prepare for Trouble Shooting
____________________________
 A.  Verify that following circuit breakers are closed: AFC WARN DC (P6 panel) A/P F/D SYS A AC (P7 panel) A/P F/D SYS A PITCH DC (P7 panel) A/P F/D SYS A ROLL DC (P7 panel) F/D SYS C AC (P7 panel)(on airplanes without P126 panel) F/D SYS C DC (P7 panel)(on airplanes without P126 panel) A/P F/D SYS C AC (on airplanes with P126 panel) A/P F/D SYS C PITCH DC (on airplanes with P126 panel) A/P F/D SYS C ROLL DC (on airplanes with P126 panel) A/P F/D SYS B AC (P7 panel) A/P F/D SYS B PITCH DC (P7 panel) A/P F/D SYS B ROLL DC (P7 panel) CAPT FLT INST SW RELAYS - F/D (P7 panel) F/O FLT INST SW RELAYS - F/D (P7 panel)
 CAUTION: MAKE SURE EQUIPMENT COOLING SYSTEM IS OPERATING BEFORE TURN-ON
_______ OF ELECTRONIC SYSTEMS, OR DAMAGE TO EQUIPMENT MAY RESULT. EQUIPMENT COOLING SYSTEM MUST BE SET FOR NORMAL COOLING AS DESCRIBED IN 21-58-00.
 B.  Place switches on mode select panel as follows: course transfer - DUAL, nav mode select - HDG, all others OFF.
 C.  Place captain's FLT DIR CMPTR select switch (P1 and P3 panel) to position C, and first officer's, to B.
　
中國航空網 m.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：747飛機維護手冊AMM CHAPTER 34 - NAVIGATION 第34章導航1(145)