A320 PWS Auto

[Rogerr]

I did some research on the PWS on our A320 fleet. The PWS operates below a certain Altitude with the weather radar turned on. In addition I found out that the PWS operates when the switch is in the AUTO position if the following conditions are fullfilled, even with the weather radar switched off:

-one engine running
-Ground Speed above 30kt or longitudinal acceleration above a given threshold during at least 0.5s.

Does anybody know the threshold of the longitudinal acceleration? I have been wondering if the PWS would turn on during Taxi In or Taxi Out with a switched off weather radar.

[AerocatS2A]

I don't know the answer to your specific question, but I would suspect that the 30 knots ground speed and what ever the acceleration value might be, is intentionally chosen to prevent activation while taxiing (max taxi speed at my employer is 30 knots).

[OPEN DES]

Multiscan:
0.07g

RDR-4000:
0.15g

[Rogerr]

Thank you for your responses.

​​​​​​I'm surprised about the low g-values. Wouldn't that mean that the PWS with the switch in Auto (Radar switch Off) would turn on with the commencement of taxi or almost every break application?

[pineteam]

Thank you for your responses.

​​​​​​I'm surprised about the low g-values. Wouldn't that mean that the PWS with the switch in Auto (Radar switch Off) would turn on with the commencement of taxi or almost every break application?

I really doubt it. I never saw the PWS turning on during taxi.

[Fursty Ferret]

It doesn’t matter. Weather radars are comparatively low emitters (you’ll pick up a greater dose standing in front of your home microwave than you would from a modern weather radar).

[FlightDetent]

Technical: n.b. The different radar boxes' logic varies w.r.t. AUTO self-activation during ground ops.

[pineteam]

It doesn’t matter. Weather radars are comparatively low emitters (you’ll pick up a greater dose standing in front of your home microwave than you would from a modern weather radar).

Underrated comment. Many pilots are unaware of this. What you wrote just now is also written pretty much word for word in the Honeywell weather radar manual. Lol.

[Rogerr]

Thank you for all your responses. I do know that weather radars in our A320s are far away from being harmful to ground staff. Nevertheless I was just surprised by the activation logic of the pws in auto, which is why I started this thread.

To me it doesn't make any sense that the pws would activate with such low g-values, which are most likely reached during normal ground ops taxi.

[AerocatS2A]

Thank you for all your responses. I do know that weather radars in our A320s are far away from being harmful to ground staff. Nevertheless I was just surprised by the activation logic of the pws in auto, which is why I started this thread.

To me it doesn't make any sense that the pws would activate with such low g-values, which are most likely reached during normal ground ops taxi.
Surely you only turn it to auto when you would have the WX Radar on anyway? So if it’s safe for the radar it’ll be safe for the PWS. Having low activation values would ensure that if the WX radar was off for take off with the PWS in auto, you will still get the PWS operating early in the take off roll.

[pineteam]

To me it doesn't make any sense that the pws would activate with such low g-values, which are most likely reached during normal ground ops taxi.
0.07 is not that low I believe. In our old SOP the weather radar was only turn ON at pilots discretion and it was very common in winter/Cavok days to fly with radar off. PWS in the other hand was always turned on. And I never saw it get activated during taxi. When it get activated it shows on the ND. I saw it few times get activated when overflying another traffic.

[FlightDetent]

Sometimes you are dead-certain happy the old days are over, right?

Max radited output of the 'classic' A320 radar = 120 W. As per the Radio Station Licence.

No need to take my word for it, own research is always better.

​​

[Rogerr]

Sometimes you are dead-certain happy the old days over, right?

Max radited output of the 'classic' A320 radar = 120 W. As per the Radio Station Licence.

No need to take my word for it, own research is always better.

​​

I thought only the Multiscan and Honeywell had such a low and unharmful output. So the max. 120 W is also true for older generations of A320?

[vickers vanguard]

I thought only the Multiscan and Honeywell had such a low and unharmful output. So the max. 120 W is also true for older generations of A320?

I can confirm , Multiscan from RC is about 45watts

[FlightDetent]

If only they chanelled that energy into a narrow beam away from the pilot, and perhaps installed a high tensile steel and aluminum bulkhead shield between the emitter unit and our seats.

You know, just to make sure it is safe.

[FlightDetent]

BTW how low does your microwave go? Mine bottoms out at 300W