BOX INS 3VHF NAV RECEIVER NO. 3
MILES GND SPEED
VOR/ILS 2
INTERNALS SAME
I N
AS INS NAV
S
F/O VOR/ILSINTERNALS SAME
1
UNIT NO. 1
RELAY B INS 2AS VHF NAV
D
INS
A
INTERNALS SAME
L
RECEIVER NO. 1
E
F/O INSAS VHF NAV B231
F/O VOR-ILS/ TR VHF NAV RECEIVER NO. 2 TRANSFER
INS NAV UNIT NO. 2 CONTROL PANEL NO. 1 INS RELAYACCESS BOXRELAY
F/O HSI
INTERNALS SAME
VHF NAV CONTROL PANEL NO. 2
AS DME NO. 1
DME NO. 2 INTERROGATOR
INS Nav Data Simplified Switching Schematic
Figure 13 (Sheet 2)
EFFECTIVITY
CONFIG 3AIRPLANES WITH LTN-72RL OR 799 Page 35/36 LTN-92 INS Apr 25/91
34-41-00
PLATFORM HEADING PLATFORM HEADING VALID ROLL ATTITUDE (NO. 1) PITCH ATTITUDE (NO. 1) ATTITUDE FLAG (PRIM) INERTIAL NAVIGATION UNIT 1 E62-E64
E65 E15-E17 E27-E29
E18
E18 B49-B51 B59-B61 E62-E64
E65 B62-B64 B52-B54
B44
E18 E27-E29 E15-E17 E62-E64
E65 ATTITUDE FLAG (PRIM) PITCH ATTITUDE (NO. 1) ROLL ATTITUDE (NO. 1) PLATFORM HEADING PLATFORM HEADING VALID INERTIAL NAVIGATION UNIT 2
COMPASS COUPLER NO. 2 (MHRS-2)
INS Attitude and Compass Stabilization Simplified Switching Schematic
Figure 14
EFFECTIVITY
CONFIG 3 AIRPLANES WITH LTN-72RL OR
799Page 37/38 LTN-92 INS
34-41-00
Apr 25/91
26V AC FAIL OP 26V AC STBY BUS 26V AC STANDBY
26V AC FLT INST BUS NO. 2
28V DC ESS FLT INST BUS
28V DC FLT INST BUS NO. 2
26V AC FLT INST BUS NO. 2 26V AC FAIL OP
26V AC FAIL OP 26V AC STANDBY 28V DC ESS FLT INST BUS
28V DC STANDBY
26V AC FAIL OP 26V AC FLT INST BUS NO. 2
28V DC FLT INST BUS NO. 2
28V DC FLT INST BUS NO. 2
SWITCH INS
INS Power Distribution and Control Figure 15
EFFECTIVITY
CONFIG 3 AIRPLANES WITH LTN-72RL OR 799 Page 39/40
34-41-00LTN-92 INS Apr 25/91
(1)
If the INS system is operating and ground power is removed, the INS automatically transfers to battery power. In order to protect the INS batteries from inadvertent discharge when the airplane is sitting on the ground, a ground crew call horn, located in the nose wheel well, activates 30 (| 10) seconds after the INS transfers to battery power.
(2)
The battery warning system consists of a battery warning logic module, an INS warning relay and a ground crew call horn.
(3)
The ground crew call horn is activated when:
(a)
Any one or more INS systems operates on battery power for approximately 30 seconds.
(b)
The airflow detectors detect no airflow in the equipment cooling air ducts.
(c)
The ground crew call button (on P5 overhead panel) is pressed.
B. Battery Warning Logic Module
(1)
The battery warning logic module is a relay driver that provides DC power to energize the INS warning relay, when the INS has been operating on battery power for about 30 seconds.
(2)
When any INS is not off, a 28-volt dc INS NOT OFF signal is applied to the input of OR gate A, resulting in an output applied to the INS NOT OFF side of AND gate C.
(3)
When any INS is operating on battery power, a 28-volt dc BATTERY IN USE signal is applied to the input of OR gate B, resulting in an output applied to the BATTERY IN USE side of AND gate C. There is a time delay of approximately 30 seconds between the input to gate B and the input to gate C.
(4)
When both the INS NOT OFF signal and the BATTERY IN USE signal are applied to gate C, the output of gate C causes the INS warning relay to close. When the relay is closed dc power is applied to the ground crew call horn, causing the horn to sound.
20. INS Signal Interface
____________________
A. External Signal Inputs (Fig. 2)
(1) True airspeed and barometric altitude from the central air data computers, DME range from the DME interrogators and VOR omnibearing from the VHF navigation receivers are external signal inputs to the INS.
B. Output Signal Interface
(1) The overall INS interface is shown in Fig. 2. In addition to the displays, the INS provides the following:
(a)
Stabilization signals to the weather radar system, keeping it level during normal maneuvers
(b)
Navigation data and attitude to the autopilot/flight director system
(c)
Rate and acceleration signals (autoland parameters) to the A/P-F/D landing and rollout control units.
(d)
Pitch attitude reference to the auto throttle system
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