What is "GP"?

ScottM

ScottM

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iBazinga!
in this NOTAM?

!SBM 08/013 SBM NAV RWY 21 ILS GP OTS TIL 0912172200

I get that this is the Sheyboygen (KSBM) ILS for runway 21 but what is the out of service GP? Did they mean GS for glide slope?

I am heading up there later today and may need to shoot an approach in so I want to make sure if I need the ILS that it is fully functional or at least can live with its OTS limitations.
 
glide path?
Id call tower anyway..many times things are reported ots on notam but on realitytam they aren't.
 
mantakos said:
This doesn't seem like the proper abbreviation to use, I suspect that it's supposed to be GS for glide slope. A glidepath doesn't strike me as something that can be OTS.
-harry
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Right or wrong, that's very commonly how they issue the NOTAM.
 
I wonder if they are using GP ( Glide Path ) to have a common term for ILS and WAAS approach?
 
Let'sgoflying! said:
glide path?
Id call tower anyway..many times things are reported ots on notam but on realitytam they aren't.
Click to expand...

But sometimes the NOTAM is correct and the tower doesn't have a clue. This seems to be especially so for towers that aren't 24 hours from what I've seen. I'm not sure what the legality of using a NAVAID that has been NOTAMed out even if the tower says it's good.
 
smigaldi said:
in this NOTAM?

!SBM 08/013 SBM NAV RWY 21 ILS GP OTS TIL 0912172200

I get that this is the Sheyboygen (KSBM) ILS for runway 21 but what is the out of service GP? Did they mean GS for glide slope?

I am heading up there later today and may need to shoot an approach in so I want to make sure if I need the ILS that it is fully functional or at least can live with its OTS limitations.
Click to expand...

GP is glide path. The KSBM ILS RWY 21 is unavailable, you'll have to get by with the LOC/DME RWY 21.
 
Let'sgoflying! said:
glide path?
Id call tower anyway..many times things are reported ots on notam but on realitytam they aren't.
Click to expand...

No tower at KSBM. Working or not, if a NOTAM says it's out of service a clearance for the approach should not be issued.
 
jtheune said:
I wonder if they are using GP ( Glide Path ) to have a common term for ILS and WAAS approach?
Click to expand...
How would the GP for a WAAS go OTS?

There has been work going on at KSBM that has displaced the threshold form time to time in that case the GP for a WAAS may not longer be accurate and I could see a NOTAM being issued to that affect. But it is my understanding that the GP information for a WAAS approach is generated in the GPS itself.
 
MikePapa said:
But sometimes the NOTAM is correct and the tower doesn't have a clue. This seems to be especially so for towers that aren't 24 hours from what I've seen. I'm not sure what the legality of using a NAVAID that has been NOTAMed out even if the tower says it's good.
Click to expand...
I know you are speaking in generalities here. But int his case, there is no tower to call, either in the air or on the ground. I doubt approach would know anymore or less than what the NOTAM states. The NOTAM itself was probably issued by the airport manager.

Now if this were at a towered airport and they told you the NOTAM had not been updated but the navaid was good you might be legal. At least you now have it on tape that they have told you so.
 
smigaldi said:
How would the GP for a WAAS go OTS?

There has been work going on at KSBM that has displaced the threshold form time to time in that case the GP for a WAAS may not longer be accurate and I could see a NOTAM being issued to that affect. But it is my understanding that the GP information for a WAAS approach is generated in the GPS itself.
Click to expand...

No not that the GP for the WASS was OTS, my comment was that they may be referring to both a GS for a a ILS and a GP for a WASS using the generic term GP so as to have a single term both kinds of things. The notam would say the GP for the ILS was OTS
 
smigaldi said:
The NOTAM itself was probably issued by the airport manager.
Click to expand...

Probably not. The GS either failed or was taken out of service for maintenance or construction. If it was taken out of service the NOTAM would be generated by FAA Tech Ops. If it failed it would take two pilot reports or a report from the monitoring agency to generate the NOTAM.
 
Unbeliever said:
One way: A tree grows into the exclusion zone for the glidepath.

--Carlos V.
Click to expand...

Or the RAIM is lost due to a satellite or ground station outage. But I'm pretty sure those are NOTAMed as WAAS and not GP.
 
MikePapa said:
Or the RAIM is lost due to a satellite or ground station outage. But I'm pretty sure those are NOTAMed as WAAS and not GP.
Click to expand...

Your correct in concept, but a WAAS GPS doesn't use RAIM, but monitors HPL and VPL to determine if they exceed criteria for the approach.

Occasionally I see a NOTAM for an airport reporting that WAAS may be unreliable during a specific time period for a RNAV approach. This doesn't mean that the GP capability is unavailable, but that it may be.

In the technical documents, GP is used to describe the WAAS glidepath and GS is used to describe the ILS glideslope. I am sure some use them interchangeably.
 
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