cvbcbcmv
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Question About Airbus Gpws

Mon Apr 23, 2012 3:59 am

Hey guys, I don't post here very often so please forgive me if there is a better section for this question, but I was just wondering...

When an airbus plane is landing, we'll use an a320 for example, somewhere around between 300 and 400 feet above the ground, and above one hundred feet (like it sounds) in my ears I hear something like, "hundred above." It sounds something like that to me. What is this actually and what does it mean? Any help is appreciated. (I'm not a pilot, let me just clear that up so nobody thinks I fly these planes and I'm asking a question like that)

I considered the possibility maybe it's 100 above minimums, but it still calls out approaching minimums so I don't see why they would do that.
 
Mir
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RE: Question About Airbus Gpws

Mon Apr 23, 2012 4:19 am

Quoting cvbcbcmv (Thread starter):
I considered the possibility maybe it's 100 above minimums,

I do believe that's it.

Quoting cvbcbcmv (Thread starter):
it still calls out approaching minimums so I don't see why they would do that.

Just an awareness tool for the pilots. If I didn't have a system that would do that for me, I'd want the other pilot to be making the same callout on an approach.

-Mir
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RE: Question About Airbus Gpws

Mon Apr 23, 2012 4:54 am

The auto call out function of the GPWS system of the A320 varies depending on the IFR approach used.

Starting with a Visual Approach, (as entered in the FMS), the call outs will be 500', 100', 50, 30, 20, 10. (Then a "retard"call, but that is not a function of the GPWS). These are heights above ground, as assessed by the radio altimeter.

On a Cat I, ILS approach, the call outs will be 400', 100', 50', 30', 20', 10'. Again, these heights are above ground. As an MDA is entered into the FMS and not a DH, the 100 above call is made by the pilot not flying, and responded by the pilot flying.

On a Cat 2 or 3 ILS approach, where a DH is entered into the FMS and not an MDA, the call outs are different. Basically, they are 400' (above ground), then "100 above" (height above the DH), then "minimum" (the DH), then the rest depends on whether it is a Cat 2, Cat 3 Single, or Cat 3 Dual approach. Where warranted, the 100, 50, 30, 20, 10 auto calls are made.

I say where warranted, as the DH is 100' AGL for Cat2, 50' AGL for Cat 3 Single, and No DH for Cat 3 Dual.

.... and you thought it was a simple question!
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bueb0g
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RE: Question About Airbus Gpws

Mon Apr 23, 2012 5:18 pm

Quoting cvbcbcmv (Thread starter):
When an airbus plane is landing, we'll use an a320 for example, somewhere around between 300 and 400 feet above the ground, and above one hundred feet (like it sounds) in my ears I hear something like, "hundred above." It sounds something like that to me. What is this actually and what does it mean? Any help is appreciated. (I'm not a pilot, let me just clear that up so nobody thinks I fly these planes and I'm asking a question like that)

You have it on some Boeing's too, for example BA's. Here's a video from the flightdeck of a 744:

http://www.youtube.com/watch?v=gMZPwzdGcTk

A female voice calls "50 above" and "decide", replacing "approaching minimums" and "minimums" before going back to the standard GPWS voice for 100. And yes, it does just mean minimums, but is somewhat more explicit.
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cvbcbcmv
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RE: Question About Airbus Gpws

Mon Apr 23, 2012 10:44 pm

Thanks for the answers guys, it's greatly appreciated!

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