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(c) The auxiliary EICAS display provides an alternate display for the captain's or first officer's ND weather radar data. The auxiliary EICAS is identical to the ND's and receives weather data when the captain's or first officer's LWR CRT transfer switch is placed to the ND position.
(10) ND Weather Radar Alphanumeric Displays (Fig. 4)
(a)
Three range arcs divide the display into four equal sections. One-half the selected range (white numerics) is placed beside the center range arc. It equals one-half of the total display range selected on the EFIS control panel.
(b)
The range arcs are always displayed in the EFIS MAP modes. In the expanded VOR, APP and MAP modes, range arcs are displayed only when weather data is also present.
(c)
Weather radar mode, tilt and gain messages are located in the lower left of the ND. 1) Mode message - TEST, WXR, WX+T and MAP 2) Gain message VAR is displayed when gain control is in
manual for all modes of operation. 3) Antenna tilt messages of 0 to +15 or -15 are displayed.
(11) Weather Radar Mode Displays (Fig. 5)
(a) The weather radar mode displays are described as follows:
1) WX (weather) - The ND's show areas of heaviest rainfall in red, the next lower level of rainfall in yellow, and the least rainfall in green.
2) WX/TURB (weather plus turbulence) - the ND's display weather the same as in the WX mode. In addition, any turbulence return which indicates area of rainfall and winds within 40 miles of the airplane are displayed in magenta.
3) MAP - the ND's display terrain mapping returns in red, yellow and green.
(12) Predictive Windshear Operation Functions
(a) Alert Annunciations and Windshear Alert Regions
1) The predictive windshear system (PWS) provides the flight crew with two levels of alerting for detected windshear events. These two levels are PWS cautions and PWS warnings. The differentiation between the two levels is based on the proximity of the detected windshear to the airplane. Windshear detected in close proximity to the airplane are call a windshear warning. All other detected windshear events are called windshear cautions. The alert regions for these windshear events are shown in Fig. 6.
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2) In order to detect windshear, the PWS scans an area that is plus or minus 25 degrees from the magnetic heading of the airplane. Windshear cautions and warnings are annunciated below 1200 above ground level (AGL).
3) A PWS caution is generated when a windshear event is in the caution area defined by the takeoff roll alert region or the approach and go-around alert regions shown in Fig. 6.
4) A PWS warning is generated when a windshear event is in the warning area defined by the takeoff roll alert region or the approach and go-around alert regions shown in Fig. 6.
(b) Takeoff Mode of Operation 1) The PWS is automatically activated according to the following conditions and as shown on Fig. 7. a) The airplane is on the ground while the engines are at takeoff thrust. The takeoff discrete is set from the EIUs to the WXR R/T. b) The airplane is between 50 and 2300 feet AGL. c) The WXR switch on the EFIS control panel is set to the
on position.
OUTER RANGE RING
HALF SELECTED
RANGE SCALE
AIRPLANE SYMBOL
ND ALPHANUMERIC AND WEATHER DISPLAYS
Weather Radar Displays
Figure 4
WEATHER DISPLAY
MAGENTA
RED MODE
(CYAN)
ANT TILT (CYAN)
GREEN YELLOW GAIN (CYAN)
AREAS ARE DARK (NO COLOR) SHOWN REVERSED FOR ILLUSTRATION PURPOSES
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