1
LEG SWITCH, XTK, TKE, DA, 3 INS DA NAV VALID NAV VALID TO A/P-F/D 2
NAV
ROLL COMPUTER-A 1ALERT
VALID
RAD
TKE+DA
3
TRUE HDG
TO/FROM
VALID
DA
TKE
INSTR SW
XTK
MILES GND SPEED
ACCESS BOX
DIGITAL DATA
NAV VALID
R
NORM 1
A
DIGITAL DATA VALID CAPT INS
D
TRANSFER RELAY
LEG SWITCH
1 G
TO/FROM
S
PLATFORM HDG
COMPASS
COUPLER 1
A
PLATFORM HDG VALID
L E R T
ALERT
INS 3
INS NAV UNIT NO. 1 ALT 3 XTKCAPT INS NAV VALID
PLATFORM HDG
CAPT ATT/COMP
CAPT HSI
PLATFORM HDG VALID
STAB RELAY INS 1 TRUE HDG
DIGITAL DATA
28V DC ESS
DIGITAL DATA VALID
FLT INST BUSLEG SWITCH, XTK, TKE, DA, CAPT TKE+DANAV VALID NAV VALID TO A/P-F/D
FLT INST SW
TRUE HDG
INS 2
ROLL COMPUTER-B RELAY - INS INS
CAPT INS SWITCH 28V DC FLT TRUE HDG VALID
CAPT RAD/INS INST BUS 2 DA RELAY
INS 3
TO/FROM
F/O FLT INST SWTKE CAPTAIN
RELAY - INS SELECTEDXTK RADIO/NAVP7 ELEX CB PNLTKE+DA DATANORM 2 INS 2
LEG SWITCH
ALERT
F/O INS NAV VALID
COMPASS
INS NAV UNIT NO. 2 COUPLER 2
INS 1
PLATFORM HDG
F/O INS SWITCH
PLATFORM HDG VALID
ALT 3
1
LEG SWITCH
2
F/O ATT/COMPDIGITAL DATA VALID
3
STAB RELAY
DIGITAL DATA
MILES GND SPEED
TO/FROM
XTK
1
I N
2 INSTR SWTKE RAD S
3 INS ACCESS BOX
2
DA F/O SELECTED
NAV
TKE+DA
1 RADIO/NAV DATA
VALID
2
A
L
ALERT 3
E R
LEG SWITCH, XTK, TKE, DA,
TRUE HDG NAV VALID TO A/P-F/D INS T
ROLL COMPUTER-C
TRUE HDG VALID F/O INS
F/O RAD/INS
TRANSFER RELAY
NAV VALID RELAY
F/O HSI
(SAME SIGNALS AS CAPT HSI)
INS NAV UNIT NO. 3 INS NAV Data Simplified Switching Schematic Figure 15 (Sheet 2)
EFFECTIVITY
CONFIG 1AT 701-750 799 Page 45/46
34-41-00
Oct 25/80
(2)
When any INS system is on, 28 volts dc is applied to one of the INS-NOT-OFF inputs of the battery warning logic module. With a 28-volt dc input available at any one of the INS-NOT-OFF inputs, the voltage level at point A is 18 volts and the voltage levels at points B and C and at Q2 base is 0.6 volt which is not high enough to cause Q2 to conduct.
(3)
When a 28-volt dc BATT-IN-USE signal is applied, the voltage level at point C is raised to 28 volts and the capacitor begins to charge. After a time delay of approximately 30 seconds, Q2 base voltage increases enough that Q2 begins to conduct. Q2 grounds Ql base causing Ql to conduct which provides a 28-volt output to the INS warning relay.
(4)
Removal of the 28-volt BATT-IN-USE input causes the battery warning logic module to reset.
13. INS Updating Annunciators (AF 116-150, 152-199; LH 011-030, 051-070, 082-099,
_________________________ AZ 221-299; MD 501-599; GN 601-699; AT 701-750; VM 751-799; less airplanes with PMS (Fig. 1 and 2)
A. On airplanes without PMS, whenever an INS is being updated the corresponding (INS-1 or 2) annunciators on both captain's and first officer's main instrument panels will change from black to green display. When discrete updates are being entered the green will be displayed briefly. During automatic update this display will be continuous. These annunciators alert the captain and first officer that each INS is in the RADIO updating mode of operation and that a possible abrupt change in displayed position or position error may be accomplished by a corrective maneuver if on autopilot.
B. On airplanes with PMS, whenever the INS inertial present position is being updated, the corresponding (INS-1 or 2) annunciators on both captain's and first officer's main instrument panels will change from black to green. When discrete updates are being entered the green will be displayed briefly. During automatic update the green display will be continuous. These annunciators alert the captain and first officer that the INS displayed present position is being updated by the PMS and that a possible abrupt change in displayed position may be accomplished by a corrective maneuver if on autopilot.
14. INS Signal Interface
____________________
A. External Signal Inputs (Fig. 2)
(1) External signal inputs to the INS are barometric altitude and true airspeed from the central air data computers (CADC). CADC No. 1 supplies INS No. 1 and No. 3 and CADC No. 2 supplies INS No. 2.
(2) On AF 116-150, 152-199; LH 011-030, 051-070, 082-099; AZ 221-299; XA MD 501-599; GN 601-699; AT 701-750; VM 751-799; less airplanes XA with PMS; see *[1], 34-41-00 page 1;
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