*
Traffic alert and collision avoidance system (TCAS)
*
Weather radar (WXR) -For predictive windshear (PWS) alerts.
The WEUs amplify and send this audio to the aural warning speakers.
The WEUs also send a takeoff configuration arm signal to the weather radar. Weather radar uses this discrete in the logic that automatically turns on PWS during takeoff.
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WES -ANALOG INTERFACES -1
PWS Warning Discrete
The predictive windshear function in WXR sends a warning discrete to the WEUs. This discrete causes the master warning lights to come on when there is a PWS warning alert.
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Fire Warning Inputs
The warning electronic units (WEUs) receive engine fire and APU fire signals from the engine and APU fire detection cards. The WEUs use these inputs to make a fire bell aural and to make the master warning lights come on.
Hydraulic Interface Modules Interface
The WEUs supply autoslat enable signals to the hydraulic interface modules (HYDIMs). The HYDIMs use these signals to increase available hydraulic flow for the slats.
Main Gear Steering Control Unit Interface
The main gear steering control unit (MGSCU) supplies main landing gear steering signals to the WEUs. The WEUs use these signals for takeoff configuration warning.
Stick Shaker Outputs
The stall warning function of the WEUs makes the stick shaker actuators come on when the airplane is near a stall.
Aural Warning Speaker Interface
The left WEU supplies alert aurals to the left aural warning speaker. The right WEU supplies alert aurals to the right aural warning speaker.
The two channels in each WEU supplY an aural arm signal to the opposite WEU. An alert aural comes on when at least two channels generate the aural arm command.
The aural warning speakers send speaker monitor signals to the WEUs. The WEUs use these signals to check the speaker status.
Program Pins
Each WEU has program pins. Some program pins identify each WEU (left or right). The WEUs have other program pins, but they are for flight test only.
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WES -WARNING ELECTRONIC UNIT
Purpose
The warning electronic unit (WEU) receives inputs from various systems. The WEU uses these inputs to show warning and alert indications to the flight crew.
WEU Channels
Each WEU has two channels that:
*
Make alert aurals
*
Do airplane configuration warning
*
Do stall warning computations
*
Process crew alerting signals.
The WEUs send data to each other. The WEU supplies warning and alerting outputs only when at least two out of the four channels make an output.
Software Loading
The WEUs must have software loaded in them. You use the maintenance access terminal (MAT) to load software into the WEUs.
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WES -AURAL WARNING SPEAKER
General
The aural warning speakers supply alert aurals to the flight crew.
There are two aural warning speakers. Each speaker gets 28v dc. The 28v dc energizes an amplifier in the speaker.
Each aural warning speaker supplies a speaker monitor signal to its WEU.
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WES -MASTER WARNING LIGHTS
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