B737-800 MONITOR RADAR DISPLAY happened twice on same situation.

[flyzhz]

I really do not understand why MONITOR RADAR DISPLAY warming happened twice on same situation. Hope some friends can help me.
The first time ,at about 9 am, August ,2013.The weather is very nice and sunny,CAVOK,wind calm.After take-off,at about 400AGL,the MONITOR RADAR DISPLAY warming came out.CAP and I ,as FO,both surprised.Two weather reader automatically turned on,windshear symbol showed on ND.Everything else is normal.
The second time,at 9 pm ,04/02,2014.Everthing is just like the first time,but the altitude is 1000AGL.
The two warmings happened on same aircraft,same airport ,same runway,same good weather.
I am not sure what is going on .Hope somebody can help me.Thanks a lot!

[Capn Bloggs]

My type, not a 737, issues occasional spurious "Go Around, Windshear Ahead!" reports on short final for a particular runway. Never any weather in sight.

Processing bug in PWS methinks...

[Mikehotel152]

It's well known that certain airports are susceptible to false PWS warnings. There is a Boeing Bulletin from April 2007 on it:

Airlines have reported false Predictive Windshear System (PWS) alerts at a number of airports. The anomaly is only applicable to PWS alerts; all Reactive Windshear alerts must be considered valid. These false alerts are limited to airplanes equipped with the Honeywell weather radar with PWS (transceiver part numbers 066-50008-0406 and 066-50008-0408) and have been predominantly reported by operators of 737NG airplanes.

Etc etc.

[flyzhz]

thanks a lot!

[737aviator]

Our airline alerts us to airports at where this is quite common; perhaps yours has something similar?

[BARKINGMAD]

I have had hard G/A warning @KEF a few years ago, took capts executive decision NOT to perform the manoeuvre.

As we were at the time taxying out to the HP for the departure, I thought it wiser not to try TOGA etc as quite a few people would have got upset!!

The only thing we could think of was the widget confusing the 757 on approach for an approaching storm cell and advising us accordingly.

It shouldn't have happened, but it did, another minor mystery which will tickle me in my dotage!! :)

[Skyjob]

BARKINGMAD:
As we were at the time taxying out to the HP for the departure

Question: why was your weather radar on when taxiing? Does you manual allow the use of weather radar with close in proximity of people (read aircraft in front or on approach)?

[BARKINGMAD]

Skyjob. like a lot of airline weather radar info, my manual said not a lot, compared to what it could have said.

Give me the credit of sufficient experience, 17+k hours, NOT to activate the radar within 15m of live people. This is an OM limitation.

Give me the credit, having consulted the AMM on disc in the ground engineers office, for NOT activating it within 300 feet of any bowser, terminal wall, aircraft side or other reflecting surface which would reflect sufficient of its normally weak pulse into its own orifice sufficient to risk damage to the sensitive receiver circuitry. How many out there are aware of this limitation?

I always performed a "confidence check" of the Wx radar before departure when anticipating those weather conditions specified as unacceptable in the DDG/MEL for operation with unserviceable radar.

This procedure for the confidence check was IAW the MM and taking the same precautions.

I carried out this check and used the Wx radar airborne all the time so I did not end up in the news with a smashed radome, damaged forward-facing surfaces and frightened pax like some others in the Flight Safety pages.

Please quote to me, chapter and verse, where it says I may NOT taxi out with the radar active having observed the aforementioned precautions.

And what adverse effect would it cause on the approaching aircraft by so doing?

[Kefuddle]

737 NG wx limitation is not within 50' or in a hanger. If you don't taxi out with the wx radar on with weather around to check yon options, then you must be truly barking mad, not barkingmad who seems not to be barking nor mad.

FWIW, Boeing manual says PWS can be activated by particulate matter. It doesn't go into any more detail than that.

[de facto]

Question: why was your weather radar on when taxiing? Does you manual allow the use of weather radar with close in proximity of people (read aircraft in front or on approach)?

Yeah there are always **** loads of people hanging around taxiways:ugh: