K77656
Navigation Warning System Component Location 5C8
34-29-0 Figure 1 Jun 20/85
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
C. Roll and pitch signals are monitored in the same manner as heading except the signals come from the ADI. However, the threshold detectors in these circuits provide an output to activate the warning lights when the input signals have a difference of 4 degrees or greater.
D. When glide slope capture is generated in the computer of the captain's flight director system, a trigger signal is applied which changes the threshold level in the heading, roll and pitch channels. When triggered, the threshold level is reduced from 4 to 3 degrees in pitch and roll and from 6 to 4.5 degrees in heading. The trigger signal, designated GLIDE SLOPE CAPTURE in the diagram, also activates the altimeter channel when altimeter comparison is made to operate.
E. Localizer and glide slope deviation are compared separately in two comparators. The signals are modified and amplified before being fed to threshold detectors. The operations performed on the localizer and glide slope deviation signals are identical. If the output from either comparator (localizer, or glide slope) exceeds a certain predetermined value, the appropriate threshold detector will provide an output to the associated warning lights. In order to prevent operation of the comparators, other than when the deviation signals are present, they are activated by mode signals. When both navigation units are in the ILS mode, 28 volts dc is applied to both comparators (provided the nav transfer switch is in normal position). After a suitable time delay, the comparators become active. In the case of the glide slope comparator, in addition to the navigation units being in the ILS mode, the glide slope high level (Super) flag signals must be present. With the super flag signals present, the glide slope comparator will be activated. The glide slope super flag signals appear only when glide slope receivers are activated, and glide slope signals of a predetermined value are present to them. The localizer and glide slope channels are not activated when the VHF NAV transfer switch is set to BOTH ON 1 or BOTH ON 2.
F. The warning lights remain on for as long as a fault condition exists. The lights can be dimmed by pushing on them. The lights will remain dimmed until the fault is cleared, at which time they are automatically reset to their original (bright) condition.
G. The comparator warning unit and the lights may be tested by pressing the test button. When the button is depressed, all the warning lights (except MON PWR) will light, indicating that the comparator warning unit is functioning.
H. A switch and several test lights are provided on the comparator warning unit for system test purposes (Fig. 1).
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May 01/76 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 34-29-0 Page 3
K77704 K77891
Navigation Warning System Schematic 557
34-29-0 Figure 2 (Sheet 1) May 01/76
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
5C8 Navigation Warning System Schematic
Jun 20/85 Figure 2 (Sheet 2) 34-29-0
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
NAVIGATION WARNING SYSTEM -ADJUSTMENT/TEST
EFFECTIVITY
GJ ALL EXCEPT B-2509 and B-2510
1. Navigation Warning System Test
A. General
(1) Prior to performing test procedures for the navigation warning system, determine that the VOR/ILS navigation, flight director, compass, and vertical gyro systems are operational.
B. Equipment and Materials
(1)
Signal generator - Instrument Flight Research Corp., Inc., type NAV-401L, or equivalent (2 required)
(2)
Calibrated tilt table (2 required)
C. Prepare to Test Navigation Warning System
(1)
Open vertical gyro CB's on P6 and P18 circuit breaker panels.
CAUTION: IF GYROS HAVE BEEN OPERATING, TURN OFF POWER BEFORE REMOVING VERTICAL GYRO AND ALLOW APPROXIMATELY 15 MINUTES FOR GYROS TO COAST DOWN. IF UNIT IS REMOVED TOO SOON, GYROSCOPIC PRECESSION COULD RESULT IN DAMAGE TO THE GYRO. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737 AMM 飞机维护手册 通讯描述和操作(133)
