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30-41-00
ALL ú ú 01 Page 5 ú Apr 10/89
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
A. Functional Description
(1)
No. 1 Left and Right Window Heat (Fig. 2)
(a)
Heating of the No. 1 windows begins when the WINDOW HEAT switches on the P5 panel are turned on. To prevent mechanical shock to a cold window, each window heat control unit increases power gradually until full power or full temperature is reached. After this ramp warmup, the control unit operates in its proportional heat mode. In this mode the control unit regulates window temperature by applying an amount of power proportional to the difference between actual window temperature and desired operating temperature.
(b)
The electrical resistance of the thermistor sensor decreases as window temperature is raised. The control unit continuously monitors thermistor resistance to determine how much power to apply to the window heater.
(2)
No. 2 and 3 Left and Right Window Heat (Fig. 3).
(a)
Heating of the No. 2 and 3 left and right windows is enabled whenever airplane electrical power is available. The window temperature is controlled by a thermostat mounted on the window. Each thermostat controls the temperature of its window by cycling open and closed. The control thermostat opens at 95-101°F (35-38°C) and closes at 87-93°F (30-33.5°C).
(b)
In case of a malfunction of the control thermostat, the overheat thermostat will open at 118-125°F (47-51.5°C) and will close at 105-112°F (40-44°C).
B. Control
(1)
To activate the No. 1 window heat system, press the WINDOW HEAT L and R switches on the anti-ice-rain removal module so that the white ON indicator appears. To deactivate the No. 1 window heat system, press the switches again. The ON indicator will disappear.
(2)
Operation of the No. 2 and 3 window heaters is automatic. No control functions are exercised.
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30-41-00
ALL ú ú 03 Page 6 ú Jun 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
FLIGHT COMPARTMENT WINDOW ANTI-ICE SYSTEM - ADJUSTMENT/TEST
___________________________________________________________
1. General_______
A. There are two tasks in this subject. The first task is an operational test for the No. 1 flight compartment window anti-ice system. The procedure for this is to do a CMC ground test.
B. The second task is a system test of the flight compartment window anti-ice system. The test has these parts:
-Do a CMC ground test on each window heat control unit
-Monitor CMC maintenance messages during a sensor failure
-Remove and install relays from the P414 panel
-Install jumper wires at the relay sockets
-Monitor EICAS messages
-Look at CMC input monitoring displays.
C. The test for the No. 1 window heat systems must be done when the outside ambient air temperature is below 85° F (29° C). The window heat control units do not apply power to the No. 1 windows when the window temperature is above approximately 85°F (29 °C).
D. The test for the No. 2 and No. 3 window heat systems must be done when the outside ambient air temperature is below 86° F (30° C). The control thermostats do not apply power to the No. 2 and No. 3 windows when the window temperature is above approximately 86°F (30 °C).
TASK 30-41-00-715-025
2. Operational Test - Flight Compartment Window Anti-Ice System____________________________________________________________
A. General
(1) This ground test commands the window heat controller to heat the flight deck windows and does a check for a rise in window temperature.
B. References
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：747-400 AMM 飞机维护手册 防冰和排雨 ICE AND RAIN PROTECTION(48)
