34-31-02
ú ú 05 Page 14 ú Mar 12/02
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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737-300/400/500MAINTENANCE MANUAL
21. Operation_________
A. General
(1)
The VOR/ILS navigation system operation consists of an operational and a functional description. The operational description is a brief overall description of the system block diagram. The functional description is a more in depth description of the system components and functional schematics.
(2)
To operate the VOR/ILS navigation system, energize load control centers P6 and P18 and close the ADI, IRS, DAA, instrument transformers and VHF NAV-1 or -2 VOR/ILS circuit breakers. Also, position the VHF NAV and IRS transfer switches on the pilots' overhead panel to NORMAL, select VOR for the RDDMI bearing pointers and select the MAN mode of operation on the VHF NAV control panels. Manually tune the systems to the local VOR station and check that the station audio output is available through the audio integrating system.
B. Operational Description
(1) A block diagram of the VOR/ILS navigation systems is shown in Fig. 3. RF signals from the VOR/LOC, localizer and glide slope antennas are fed to the navigation units. The localizer antenna is selected through the ILS relays by mode logic in the DFCS flight computers. The logic requires that an ILS frequency be tuned and the DFCS flight computers be operating with the VOR/LOC mode armed or engaged. Heading generated in the IRS is also sent from the DAA units to the RDDMI's and then to the navigation units. Navigation unit No. 1 receives magnetic heading from the captain's RDDMI while the first officer's RDDMI provides magnetic heading to navigation unit No. 2. Using these signal inputs, the navigation unit processes the signals used by the navigation system. With the VHF NAV transfer switch in NORMAL position, signal outputs of navigation unit No. 1 control the narrow pointer in both RDDMI's, and the warning flags and G/S and course deviation displays in the captain's EADI and EHSI through the left EFIS symbol generator. Signals from navigation unit No. 1 also go to the ground proximity warning; to the DFCS flight computers; to the left EFIS control panel and symbol generator; to the IRS digital/analog adapter unit No. 1 for interface with the FMCS; and to the standby/attitude/ILS indicator. Navigation unit No. 2 and the first officer's EADI, EHSI, and RDDMI operate in a similar manner. When the VHF NAV transfer switch is in BOTH ON 2 position, the captain's and the first officer's EADI, EHSI, and RDDMI receive their inputs from navigation unit No. 2. When the VHF NAV transfer switch is in BOTH ON 1 position, all instruments indicate navigation unit No. 1 outputs.
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本文链接地址:737-300 400 500 AMM 飞机维护手册 导航 NAVIGATION 2(157)