A320 PWS Activation?

[regor]

Once the predictive windshear has been switched to auto, via the Wx panel, is it activated once the throttles are at either the FLEX or TOGA position? Or should be activated as soon as it is switched on.

Does the aural message "Monitor Radar Display" occur to indicate that the PWS is active, or if it has detected a windshear.

Any references to an appropriate document would be ideal. The FCOM that I have does not mention PWS, other than showing a switch on the Wx panel.:confused:

[mcdhu]

Regor. From FCOM 1.34.60 P2, with windshear switch to AUTO, ''Predictive windshear function is activated: windshear areas are detected by the antenna scanning below 2300 ft RA, even if the tranceiver 1-2 selector is set to OFF, and displayed on the ND if below 1500 ft. OFF: No predictive windshear function.''
In addition, to get predictions, the ATC must be ON or AUTO and 1 engine must be running.

There are 4 alert levels:

Warning (Approach) gives ''GO AROUND WINDSHEAR AHEAD'' from Pierre, W/S AHEAD in red on the PFD and the windshear icon on the ND.

Warning (Takeoff) gives ''WINDSHEAR AHEAD'' twice from Pierre, W/S AHEAD in red on the PFD and the windshear icon on the ND.

Caution gives ''MONITOR RADAR DISPLAY'' from Pierre, W/S AHEAD in amber on the PFD and the windshear icon on the ND.

An advisory only gives you the icon on the ND.

One tip from me is that with the wx radar off, you will see the scanner tilt display appear in blue at the bottom right of the ND when you put the PWs to AUTO. This serves as a reminder that it is on.

Hope this all helps. It has been interesting to research!

Cheers,
mcdhu

:confused:

[Wander]

In addition to the above, "During the takeoff roll, both warnings & cautions are inhibited >100kts and <50'.
I'd like to know what effect the tilt has on it's ability to detect.
Also, can it detect without droplets to "see"?
Cheers
Wander

[mcdhu]

Wander,

The Airbus FCOM is less than helpful about how it works, but I'm pretty sure that the scanner tilt is irrelevant to its operation. As to whether it requires droplets, I guess it must have to have something to 'bite' on - however small. A google search on 'predictive windshear radar' came up with quite a few websites. I don't have time right now to look at many, but
this one (www.flwsradar.com) seemed to be a Honeywell site which might be of assistance.

Cheers,
mcdhu

[Techman]

The tilt for the PWS is controlled automatically, and is not affected by whatever tilt is set on the control panel.

If the wx radar and the PWS both are 'on', the system will scan in the wx mode when the antenna is moving counterclockwise, and in the PWS mode when moving clockwise.

[ECAM Status]

Very interesting information from MCDHU. Thanks a lot. Just a tip to everyone that flies an Airbus with the PWS installed: If your airline has not incorporated the PWS in the checklist, make sure that you switch it off during your after landing checks, as even with at least 1 engine running it continues to work if in the AUTO position. This is to ensure that marshallers and other people in the ramp are not affected by its operarion while you are taxying in.