Sweep Patterns
The antenna sweep is the same for takeoff and approach PWS modes. The PWS changes the sweep when PWS is active. Both WXR and PWS sweeps decrease to -60 to +60 degrees.
PWS and WXR Sweep Pattern
Position |
Dir |
Radar Sweep
|
Paint Sweep
|
Angle (Degrees)
|
Time
|
Sweep 1 |
L-R |
Capt WXR data updated |
Capt WXR +icon painted |
-60 to +60 |
3 |
Sweep 2 |
R-L |
Both PWS data updated
|
None |
+60 to -60 |
3 |
PWS and WXR Sweep Pattern
Sweep 3 |
L-R |
F/O WXR data updated
|
F/O WXR +icon painted
|
-60 to +60 |
3 |
Sweep 4 |
R-L |
Both PWS data updated
|
None |
+60 to -60 |
3 |
The sweep pattern may go to a PWS only mode during takeoff and approach when WXR is not selected and PWS is automatically activated. The scan is -60 to +60 degrees.
PWS Sweep Pattern
Position |
Dir |
Radar Sweep
|
Paint Sweep
|
Angle (Degrees)
|
Time
|
Sweep 1 |
L-R |
None |
None |
N/A |
3 |
Sweep 2 |
R-L |
Both PWS data updated
|
None |
+60 to -60 |
3 |
Sweep 3 |
L-R |
None |
None |
N/A |
3 |
Sweep 4 |
R-L |
Both PWS data updated
|
None |
+60 to -60 |
3 |
Wxr system - operation - failure displays wxr System Alert Messages and Display
Alert messages show on the ND when the R/T processes data that is not satisfactory. The WXR display will continue to show with an alert message.
Only one alert message shows on the ND. When the R/T processes unsatisfactory data from more than one source only the highest priority message shows. These are the alert messages and priority from highest to lowest:
WXR WEAK shows for an R/T gain calibration failure
WXR ATT shows when the selected attitude input fails
WXR STAB shows when stabilization is off.
The alert messages show on these alert lines:
Line 1 shows WXR in amber
Line 2 shows WEAK, ATT, or STAB in amber.
Wxr System Fail Messages and Display
A failure of these components causes a WXR failure:
R/T
WXR control panel
WXR antenna.
A WXR failure causes these conditions:
WXR FAIL message shows on ND
Mode, tilt, and gain messages go out of view
WXR display goes out of view.
The fail message shows on these alert lines:
Line 1 shows WXR in amber
Line 2 shows FAIL in amber.
A failure of these components will cause a PWS failure:
Loss of any RA
Loss of ADR data
Loss of IR data
Scan and tilt antenna faults
Internal WXR system faults
Loss of CAS and TAS.
A failure of the predictive windshear causes an amber PWS FAIL message on the ND.
