Joined: 11 Dec 2005
|Posted: Sun Jul 29, 2012 7:44 am Post subject: Predictive Wind Shear (Technical Notes)
• PWS provides windshear alerts when an excessive windshear condition is detected ahead of the airplane
• Immediate windshear alerts are provided when an excessive downdraft or tailwind is occurring
• PWS is enabled to provide windshear alerts 12 seconds after weather radar begins scanning for windshear.
• Prior to takeoff, PWS alerts can be enabled by pushing the WXR switch on the EFIS control panel.
• On the ground with the WXR switch pushed or not pushed, weather radar begins scanning for windshear when the thrust of either engine is in the takeoff range and thrust reversers are not unlocked or deployed.
• In flight with the WXR switch pushed or not pushed, weather radar begins scanning for windshear below 2,300 feet radio altitude and PWS alerts are enabled below 1,200 feet radio altitude.
• Weather radar provides windshear alerts for windshear events containing some level of moisture or particulate matter. Weather radar detects microbursts and other windshears with similar characteristics. Weather radar does not provide alerting for all types of windshear. The flight crew must continue to rely on traditional windshear avoidance methods.
• WINDSHEAR AHEAD - Windshear predicted close to and directly ahead of airplane. Enabled during takeoff, below 1,200 feet radio altitude.
• MONITOR RADAR DISPLAY - Windshear predicted within 3 miles and ahead of the airplane. Enabled during takeoff and approach, below 1,200 feet radio altitude.
• GO AROUND, WINDSHEAR AHEAD - Windshear predicted within 1.5 miles and directly ahead of the airplane. Enabled during approach, below 1,200 feet radio altitude.
• WINDSHEAR, WINDSHEAR, WINDSHEAR - Excessive windshear detected by GPWS. Enabled below 1,500 feet radio altitude. GPWS windshear detection begins at rotation.