Would agree from re-reading Vol 2 that the selection of Wx Radar should delete the 12 sec delay switch over.
Keep in mind that the weather radar detects microbursts and other windshears with similar characteristics. The wx radar does not provide alerting for all types of windshear. The crew must continue to rely on traditional windshear avoidance methods.
Vol 2 15.20.14
Predictive Winshear Inhibits must be kept in mind ;
During takeoff and landing, new predictive windshear caution alerts are inhibited between 80 kts and 400 ft RA, and new warning alerts between 100 kts and 50 ft
RA. These inhibits DO NOT remove existing predictive windshear alerts. Vol 2 15.20.16
Re the Predictive Windshear Symbol (as installed), the red and black symbol will show windshear location and approximate geometric size (width and depth).
Interestingly the symbols, radials and weather radra returns automatically show when ;
* predictive windshear alert occurs
* NEITHER pilot has WXR display selected
* in expanded MAP, center MAP, VOR or APP modes
When terrain display is active, weather radar display REPLACES terrain display.
Vol 2 15.10.19