PITOT AND STATIC (AIR DATA SENSORS) -ENGINE PROBE HEAT -FUNCTIONAL DESCRIPTION
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FLIGHT DECK WINDOW ANTI-ICE SYSTEM -INTRODUCTION
Purpose
The window heat system prevents ice and fog on the flight deck windows.
General Description
Electric heaters in the window laminations heat the flight deck windows.
The window heat switches enable the window heat system. With window heat ON, the window heat control units (WHCUs) control the power to the windows. With window heat OFF, the backup window heat system can operate.
The number 1 windows have a backup heat system. The backup window heat switches let you remove power from the backup window heat system for maintenance.
There are no test switches for the window heat system. The BITE automatically tests the system. You can use the MAT to do initiated BITE tests of the window heat system.
Interfaces
The left forward window heat switch arms the landscape camera window heat.
See the landscape camera window heat section for more information (SECTION 30-45).
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FLIGHT DECK WINDOW ANTI-ICE SYSTEM -INTRODUCTION
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FLIGHT DECK WINDOW ANTI-ICE SYSTEM -COMPONENT LOCATIONS
Component Locations
The window heat control panel is on the P5 overhead panel. The backup window heat panel is on the P61 overhead maintenance panel.
The two window heat control units (WHCUs) are on the E1 and E2 main equipment racks. The left forward and right side WHCU is on the E1-1 shelf. The right forward and left side WHCU is on the E2-2 shelf.
Burndy blocks for the spare window heat sensors are on the outboard ends of the E1 and E2 rack.
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FLIGHT DECK WINDOW ANTI-ICE SYSTEM -COMPONENT LOCATIONS
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FLIGHT DECK WINDOW ANTI-ICE SYSTEM -FUNCTIONAL DESCRIPTION -1
General
There are two WHCUs. One WHCU is for the left forward and right side windows. The other WHCU is for the right forward and left side windows. The WHCUs are the same.
Each WHCU has a separate power supply for each heater circuit in the flight deck windows. Each WHCU also has a separate power supply for BITE.
The power supplies for the heater circuits are 115v ac. The power supply for the BITE is 28v dc.
Each WHCU receives air/ground status from two air/ground relays. The inputs are analog. They are redundant.
Power Supply Circuits
The number 1 window uses two phase ac. The number 2 and 3 windows use single phase ac.
Air/Ground Inputs
The WHCU uses the air/ground status for these functions:
*
The WHCUs decrease the power to all of the window heaters during the first four minutes of operation on the ground
*
The WHCU inhibits initiated BITE tests in flight.
The initiated BITE tests occur during power-up of the WHCU, and when you do the window heat ground test on the MAT.
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FLIGHT DECK WINDOW ANTI-ICE SYSTEM -FUNCTIONAL DESCRIPTION -1
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FLIGHT DECK WINDOW ANTI-ICE SYSTEM -FUNCTIONAL DESCRIPTION -2
General 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：777 AMM 飞机维护手册 防冰和排雨 Ice and Rain Protection(13)
