747飞机维护手册AMM CHAPTER 34 - NAVIGATION 第34章导航2_航空信息_民用航空_通用航空

1
B XFR RLY VOR/ILS Power Block Diagram Figure 3 (Sheet 3)
EFFECTIVITY CONFIG 1
AF 152-154,172-173,191-194;

799 Page 20
GN ALL; MD ALL
34-31-00
Dec 25/85

F/O VOR/ILS RECEIVER 2
1B XFR RLY
VOR/ILS Power Block Diagram
Figure 3 (Sheet 4)

EFFECTIVITY LH 011-013,051-062,082,083,
CONFIG 1LESS AIRPLANES INCORPORATING 799 Page 21 SB 34-2261
34-31-00
Apr 25/86

OVHD CB PNL P7 RECEIVER 2
VOR/ILS Power Block Diagram
Figure 3 (Sheet 5)

EFFECTIVITY LH 014-050,063-081,084-099,
CONFIG 1 PLUS AIRPLANES INCORPORATING 799 Page 22 SB 34-2261
34-31-00
Apr 25/86
F. Functional Description, Relay Control (Fig. 4)
(1)
The selection of the two VOR/ILS receiver being used is controlled by the VOR/ILS transfer switch which, in turn controls the positions of the captain's and first officer's VOR/ILS relays. With the VOR/ILS switch in the center or normal position, the relays are set to provide data to the captain from receiver No. 1 and to the first officer from receiver No. 2. If either receiver No. 1 or No. 2 should malfunction, receiver No. 3 may be used as an alternate.

(2)
If, for example, the VOR/ILS deviation transfer switch is set to captain's alternate, 28-volt dc power will be applied through the switch to the stepping solenoid of the captain's VOR/ILS relay causing the relay to switch from the No. 1 position to the No. 3 position. While the captain's VOR/ILS relay is in the alternate No. 3 position the dc path to the first officer's VOR/ILS relay solenoid is broken, thus preventing both relays from being in the No. 3 position simultaneously.

(3)
The VOR/ILS position annunciator lights provide in indication of the VOR/ILS receiver being used by the pilots.

G. Functional Description, Antenna Switching (Fig. 5)
(1)
Radio frequency signals from the VOR, localizer, and glide slope antennas are applied to the three VOR/ILS receivers as shown in Fig. 5. Glide slope rf is hard wired, hybrid coupler or switched to the receivers from three, four or six, glide slope antennas depending on antenna configuration installed. VOR and localizer rf is switched to the receivers as determined by the mode selector switch on the AP-FD NAV mode selector panel and the position of the captain's and first officer's VOR/ILS relays. RF switches 1, 2, and 3 cause the rf from the VOR antenna to be used when the mode switch is in the INS, HDG, or VOR LOC position and rf from the localizer antennas to be used when the mode switch is in the LAND or ILS position. RF switches 4 and 5, controlled by the two VOR/ILS relays, direct the VOR/LOC rf to the two receivers that are in use.

(2)
On LH 001-010 and AF 101-114, glide slope rf is fed to the three VOR/ILS receivers through hybrid couplers from two capture antennas and one track antenna in each aft nose wheel well door. Relative position of the landing gear (doors closed or open) changes the polarity of the glide slope antennas essentially selecting the capture antennas when the aft wheel well doors are closed and the track antenna when the doors are open. On AF 115-120, 123-151, Glide slope rf is fed to the three VOR/ILS receivers through coaxial relays and hybrid couplers from two capture antennas and one track antenna in each aft nose wheel well door. Relative position of the landing gear (doors closed or open) changes the polarity of the glide slope antennas essentially selecting the capture antennas when the aft wheel well doors are closed and the track antenna when the doors are open.

EFFECTIVITY

AF 101-120, 123-154, CONFIG 1 172-173, 191-194; GN ALL; 01 Page 23 LH ALL AND MD ALL Sep 25/94

34-31-00

P126 OVHD LTPT CB PNL
VOR/ILS Antenna Schematic
Figure 5 (Sheet 3)

EFFECTIVITY LH 051-054;
CONFIG 1 AF 152-154,172-173,191-194;
799 Page 30GN ALL; MD ALL
34-31-00
Apr 25/83

RECEIVER 1
2 INSTALLED AND CONNECTED ON LH AIRPLANES
VOR/ILS Antenna Schematic
Figure 5 (Sheet 4)

EFFECTIVITY LH 051-054;
CONFIG 1 AF 152-154,172-173,191-194;
799 Page 31GN ALL; MD ALL
34-31-00
Apr 25/83

P126 OVHD LTPT CB PNL
VOR/ILS Antenna Schematic
Figure 5 (Sheet 5)

EFFECTIVITY CONFIG 1 LH O11-050,055-099
799 Page 32
34-31-00
Apr 25/86

VOR/ILS RECEIVER 1 GND (FIG. 6)
VOR/ILS Antenna Schematic
Figure 5 (Sheet 6)

EFFECTIVITY CONFIG 1 LH 011-050,055-099
799 Page 33
34-31-00
Apr 25/86

5
6
7
8 VOR/ILS Interface Block Diagram Figure 6 (Sheet 7)