Use the elevation and scan disable switches for safety to make sure that the antenna does not move while you work on or around it.
WARNING: DO NOT OPEN THE NOSE RADOME IF THE WIND IS MORE THAN 15 KNOTS. IF YOU OPEN THE RADOME IN A WIND, THE RADOME CAN MOVE QUICKLY. THIS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
WXR SYSTEM - EFIS CONTROL PANEL - OPERATION
EFIS Control Panel
These are the functions of the EFIS control panel (CP) for WXR control:
· Supplies the on and off control of the WXR R/T
· Enables the navigation displays (ND) to show WXR data
· Supplies the selection of different ND modes
· Supplies the selection of different ranges for WXR data to show on the NDs.
WXR Map Switch
These are the things that occur when you push the WXR map switch:
· The WXR R/T starts to operate
· The WXR data shows on the on-side ND.
To stop the operation of the WXR R/T, the WXR map switches on both EFIS control panels must be off.
Use the mode selector switch to select an ND mode. A WXR display can show in these ND modes:
· Expanded APP (approach) mode
· Expanded VOR mode
· Expanded MAP mode
· Centered MAP mode.
The EFIS control panel range selector has eight positions. The range selections are 5, 10, 20, 40, 80, 160, 320, and 640 nautical miles (NM). With the 640 NM range selection, the 640 NM range shows on the ND. But the WXR R/T only shows weather displays out to a maximum range of 320 NM.
The weather/turbulence mode shows turbulence data up to a maximum range of 40 nautical miles (NM). If a range more than 40 NM is set on the EFIS control panel, the NDs show weather data only.
WXR SYSTEM - SYSTEM SELECT AND SYSTEM ON/OFF
The receiver transmitter (R/T) gets 115v ac from XFR bus 2. The keep alive power supply makes unregulated and regulated 28v dc. The unregulated 28v dc power goes to the power relay in the R/T and also provides the interlock (INTRLK) signal through the WXR control panel to switch S1. S1 is held closed.
To make the WXR system operate, push the WXR switch on one of the EFIS control panels.
When you push the WXR switch, the on-side display electronics unit (DEU) supplies a ground through the WXR control panel. The ground then goes through switch S1 of the R/T. This ground lets the unregulated 28v dc power from the power supply energize the relay to close switches S2 and S3. The keep-alive power supply sends regulated 28v dc power through switch S2 to energize the WXR CP power supply. The 115v ac goes through switch S3 to energize these things:
· R/T low voltage power supply
· WXR antenna drive
· WXR cooling fan.
Certain conditions cause the predictive windshear (PWS) function to turn the WXR system on automatically. When this happens, the ground signal comes from the PWS card in the R/T instead of the DEUs.
To make the WXR system go OFF, push the WXR switch on the EFIS control panel to OFF. This removes the ON discrete from the DEU. If more than one WXR switch is on, push all of the switches to OFF.
The navigation display (ND) shows WXR system data in these modes: