KAUG Notam Question

On Mar 3, 11:22 am, Ron Rosenfeld wrote:
KAUG AUGUSTA STATE

04/001 - WAAS LPV WAAS LNAV/VNAV OTS WIE UNTIL UFN

This Notam has been posted, well, since April.

No one seems to be sure of what it means.

Translating the abbreviations into English is easy enough. The Notam
basically states that the LPV and LNAV/VNAV approaches are out of service
until further notice.

BUT,

Published guidance, that I have been able to locate, with regard to GPS
WAAS Notams indicates that the terms "unreliable" or "unavailable" should
be used and says nothing about OTS. If the Notam does read UNREL or
UNAVAIL, guidance allows you to execute the approach if the signal is
adequate.

I believe you may still shoot the approach if the receiver indicates
it's available. The NOTAM
simply prevents you from flight planning on it.

And, two days ago, the signal on an LPV approach at that airport was
adequate for my CNX80 to give me an LPV annunciation.

This is not surprising as you up near the edges of the current Service
Volume, where the availability
tends to be more sensitive. Once the reference stations to the Great
White North of you become
operational, you should see much better availability. Maybe even an
LPV-200 approach published up
there sometimes after that.

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Regards,
Jon

On 6 Mar 2007 12:04:19 -0800, "Jon" wrote:

I believe you may still shoot the approach if the receiver indicates
it's available. The NOTAM
simply prevents you from flight planning on it.

Where is that documented?

The only documentation that I've been able to locate references the terms
"unreliable" to be used for site specific notams except when the chart has
a "w" (which IS present on the KAUG NACO GPS 35 approach chart); or
"unavailable" for area-wide gps outages.

If the "w" is present, site-specific Notams are not issued for that site.
You're supposed to know that "unreliable" applies.

That documentation also explains pilot options if those Notams exist.

But I've not seen any documentation as to the meaning of a site-specific
WAAS "OTS" Notam.

My suspicion is that this Notam got into the system in error, and has never
been removed. But no one has confirmed it as yet.

But if you have documentation for what you wrote, that would be helpful in
coming up with an alternate explanation.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Ron Rosenfeld wrote:

On 6 Mar 2007 12:04:19 -0800, "Jon" wrote:


I believe you may still shoot the approach if the receiver indicates
it's available. The NOTAM
simply prevents you from flight planning on it.


I will not (cannot) get into the nuances of the NOTAMS. I am not
familiar with with 480 but I am with the 500W/530W. If the LPV
annunication is green, you are absolutely solid to fly the approach. If
the aunnication is yellow early on, it may still switch to green in time
to fly the approach. If it is green prior to the FAF it is golden.

On Tue, 06 Mar 2007 17:54:42 -0800, Sam Spade wrote:

Ron Rosenfeld wrote:

On 6 Mar 2007 12:04:19 -0800, "Jon" wrote:


I believe you may still shoot the approach if the receiver indicates
it's available. The NOTAM
simply prevents you from flight planning on it.


I will not (cannot) get into the nuances of the NOTAMS. I am not
familiar with with 480 but I am with the 500W/530W. If the LPV
annunication is green, you are absolutely solid to fly the approach. If
the aunnication is yellow early on, it may still switch to green in time
to fly the approach. If it is green prior to the FAF it is golden.

The problem *is* the nuances of the NOTAMS. For other approaches, OTS
generally means you can't use the approach. That may be why they chose to
use UNREL for WAAS notams.

The 480 also annunciates the approach that the signal quality (and
approach) will allow. It is in green letters on the various pages.

LNAV
LNAV/VNAV for either that level or an LNAV approach with advisory vertical
guidance
LPV

In addition, if the signal is not good enough to support vertical guidance,
the GP indicator will flag.
If the signal is not good enough for an LNAV approach, the CDI will flag.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On Mar 7, 7:41 am, Ron Rosenfeld wrote:
On Tue, 06 Mar 2007 17:54:42 -0800, Sam Spade wrote:
Ron Rosenfeld wrote:

On 6 Mar 2007 12:04:19 -0800, "Jon" wrote:

I believe you may still shoot the approach if the receiver indicates
it's available. The NOTAM simply prevents you from flight planning on it.

Just to be sure it's not ambiguous, in my statement above "The NOTAM"
refers to "UNREL" NOTAMs not the "OTS" case.

Basically, the Inverted 'w' and the "UNREL NOTAM" fold into the same
case, as
far as the pilot is concerned: What the receiver indicates overrides.

I will not (cannot) get into the nuances of the NOTAMS. I am not
familiar with with 480 but I am with the 500W/530W. If the LPV
annunication is green, you are absolutely solid to fly the approach. If
the aunnication is yellow early on, it may still switch to green in time
to fly the approach. If it is green prior to the FAF it is golden.

The problem *is* the nuances of the NOTAMS.

For other approaches, OTS generally means you can't use the approach.

As it did (and does for a bit longer, see below) in this case. Still
no luck finding
specific text to point you to, but OTS applies as one would expect,
e.g. the approach
disabled.

That may be why they chose to use UNREL for WAAS notams.

The SVM (Service Volume Model) has conservatism built into it. Since
it can't model certain things
very well (if at all) such as Receiver Noise, it errs on the safe
side. So the actual performance will
tend to be better. It was a tradeoff between not generating too many
False Positives and (more
importantly) minimizing the number of Missed Detections.

Too many False Alerts = Issuing NOTAMs repeatedly and the pilot isn't
seeing the rcvr flag. The confidence
that the SVM is actually providing a useful S begins to decrease,
until you just stop using the service.

Too many Missed Detections = Unacceptable. The system would not be
certified with a very low probability of HMI.

The 480 also annunciates the approach that the signal quality (and
approach) will allow. It is in green letters on the various pages.

LNAV
LNAV/VNAV for either that level or an LNAV approach with advisory vertical
guidance
LPV

In addition, if the signal is not good enough to support vertical guidance,
the GP indicator will flag.
If the signal is not good enough for an LNAV approach, the CDI will flag.

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

I just got a ahold of someone who indicated the NOTAM does indeed need
to
and shall be removed. Now that the 3rd GEO is commissioned, the
availability
in the NorthEast is good enough once again.

Personally, though, you'd have to be nuts to fly in the cold of the
last couple of days,
unless you have some way of taking the heat directly off the engine
block!

Regards,
Jon

On Mar 6, 6:46 pm, Ron Rosenfeld wrote:
On 6 Mar 2007 12:04:19 -0800, "Jon" wrote:

I believe you may still shoot the approach if the receiver indicates
it's available. The NOTAM
simply prevents you from flight planning on it.

Where is that documented?

It was 2003 since I last worked on it, will have to go dig up the
docos. I may have misspoken and the above (wrt flight planning only)
applies only for the case of the inverted 'w'.

The only documentation that I've been able to locate references the terms
"unreliable" to be used for site specific notams except when the chart has
a "w" (which IS present on the KAUG NACO GPS 35 approach chart); or
"unavailable" for area-wide gps outages.

If the "w" is present, site-specific Notams are not issued for that site.
You're supposed to know that "unreliable" applies.

Yep. The inverted 'w' definitely means you can't flight plan on it.

That documentation also explains pilot options if those Notams exist.

But I've not seen any documentation as to the meaning of a site-specific
WAAS "OTS" Notam.

I know for a fact (I coded it) that we don't output such a NOTAM, so
it had to have been manually entered, probably down at the NOCC in
Herndon.

My suspicion is that this Notam got into the system in error, and has never
been removed. But no one has confirmed it as yet.

It's not clear to me that it was initially entered in error. If they
service availability dropped below an acceptable level (due to the GEO
repositioning last year), it might sense, since the approach plates
are already out there. I've heard it's similar to taking an ILS OTS?

It's certainly possible, though, that it should be canceled, but I
haven't gotten any responses from the several voicemails I've left to
folk. Will try a few more contacts during the day...

But if you have documentation for what you wrote, that would be helpful in
coming up with an alternate explanation.

Dusting off some folders, standby 1...

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Regards,
Jon

On Mar 3, 11:22 am, Ron Rosenfeld wrote:
KAUG AUGUSTA STATE

04/001 - WAAS LPV WAAS LNAV/VNAV OTS WIE UNTIL UFN

This Notam has been posted, well, since April.


Sorry I haven't replied sooner but the NOTAM was canceled on the 7th.

Just a few clarifications on WAAS notams, which are actually explained
in the chapter 1 section 1 of the AIM. WAAS unavailable NOTAMs
indicate loss or malfunction of the WAAS system. In flight, Air
Traffic Control will advise pilots requesting a GPS or RNAV (GPS)
approach of WAAS unavailable NOTAMs if not contained in the ATIS
broadcast.

WAAS unreliable NOTAMs indicate an expected level of service, e.g.,
LNAV/VNAV or LPV may not be available. In flight, Air Traffic Control
will not advise pilots of WAAS unreliable NOTAMs, and they are
generally not offered by FSS unless requested.

When the approach chart is annotated with the inverse W (not inverted
W, Jon! That's an 'M' ha!), site-specific WAAS unreliable NOTAMs or
Air Traffic advisories are not provided for outages in WAAS LNAV/VNAV
and LPV vertical guidance.

Safe flights!

Brad

On 9 Mar 2007 05:54:31 -0800, "Brad" wrote:

On Mar 3, 11:22 am, Ron Rosenfeld wrote:
KAUG AUGUSTA STATE

04/001 - WAAS LPV WAAS LNAV/VNAV OTS WIE UNTIL UFN

This Notam has been posted, well, since April.


Sorry I haven't replied sooner but the NOTAM was canceled on the 7th.

Just a few clarifications on WAAS notams, which are actually explained
in the chapter 1 section 1 of the AIM. WAAS unavailable NOTAMs
indicate loss or malfunction of the WAAS system. In flight, Air
Traffic Control will advise pilots requesting a GPS or RNAV (GPS)
approach of WAAS unavailable NOTAMs if not contained in the ATIS
broadcast.

WAAS unreliable NOTAMs indicate an expected level of service, e.g.,
LNAV/VNAV or LPV may not be available. In flight, Air Traffic Control
will not advise pilots of WAAS unreliable NOTAMs, and they are
generally not offered by FSS unless requested.

When the approach chart is annotated with the inverse W (not inverted
W, Jon! That's an 'M' ha!), site-specific WAAS unreliable NOTAMs or
Air Traffic advisories are not provided for outages in WAAS LNAV/VNAV
and LPV vertical guidance.

Safe flights!

Brad

Yes, thanks. I noticed the cancellation. And the information you post
from the AIM is the same as was posted in guidance back in 2003. As you
note by omission, OTS is not described with regard to a WAAS NOTAM.

Best wishes,
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)