737NG GPWS ("reactive") windshear alerts?
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737NG GPWS ("reactive") windshear alerts?
Hey all...
Quick question about the 737NG's GPWS windshear alerts (not PWS).
The Boeing FCOM says this in the Warning Systems chapter:
So am I to understand that, a windshear caution has no yellow WINDSHEAR caption on the PFD below the attitude sphere? In other words, just a "WINDSHEAR, WINDSHEAR" aural warning? Then why, during the GPWS test, do we see a flashing WINDSHEAR followed by WINDSHEAR?
Also, the FCOM has no information about what data the GPWC uses to issue the windshear alerts. I assume it's something to to with rate of change of groundspeed versus airspeed... does anyone know for sure?
Quick question about the 737NG's GPWS windshear alerts (not PWS).
The Boeing FCOM says this in the Warning Systems chapter:
Windshear warnings are accompanied by WINDSHEAR on the attitude indicators and voice aural alerts.
Windshear cautions are accompanied by a voice aural alert.
Windshear cautions are accompanied by a voice aural alert.
Also, the FCOM has no information about what data the GPWC uses to issue the windshear alerts. I assume it's something to to with rate of change of groundspeed versus airspeed... does anyone know for sure?
Last edited by singletracker; 11th Jan 2011 at 05:12.
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single tracker, care to edit the colour?
That yellow is awful and almost impossible to read..No contrast.
Thanks.
That yellow is awful and almost impossible to read..No contrast.
Thanks.
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Not much info in the FCOM, is there. Maybe it's too much info for the non-engineer.
I'd guess it comes from at least part of the list the SMYD uses for stall detection.
Two independent, identical stall management yaw damper (SMYD) computers determine when stall warning is required based upon:
alpha vane angle of attack outputs
ADIRU outputs
antiice controls
wing configurations
air/ground sensing
thrust
FMC outputs.
mach compensation
The SMYD computers provide outputs for all stall warning to include stick shaker and signals to the pitch limit indicator and airspeed displays and the GPWS windshear detection and alert.
alpha vane angle of attack outputs
ADIRU outputs
antiice controls
wing configurations
air/ground sensing
thrust
FMC outputs.
mach compensation
The SMYD computers provide outputs for all stall warning to include stick shaker and signals to the pitch limit indicator and airspeed displays and the GPWS windshear detection and alert.
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grounded27
No I will not, I was being polite and the request was reasonable given it was very difficult to read.
As it is I cant help with the enquiry but was simply trying to help those who could to read the text.
Single tracker thanks.Not everyone has the same eyesight as others here.
As it is I cant help with the enquiry but was simply trying to help those who could to read the text.
Single tracker thanks.Not everyone has the same eyesight as others here.
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There's more posts in this thread about the posts than the thread.
I too think its not very clear about the difference between windshear cautions and warnings on the NG. Particularly as cautions can be treated as such and don't require GAs whereas warnings do.
I wonder how many people would reject the TO for 'Monitor Radar Display'.
I too think its not very clear about the difference between windshear cautions and warnings on the NG. Particularly as cautions can be treated as such and don't require GAs whereas warnings do.
I wonder how many people would reject the TO for 'Monitor Radar Display'.
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Also, the FCOM has no information about what data the GPWC uses to issue the windshear alerts. I assume it's something to to with rate of change of groundspeed versus airspeed... does anyone know for sure?
