IMPORTANT- Seeyou V's Strepla and airspace violations.

I have not looked at the IGC file nor US airspace.
However I do use the UK AIP to produce airspace files for my LX5000 and
SeeYou for the UK.

In the UK airspace lateral boundaries are given, primarily in terms of
reference points and
Airway widths. I translate that information into boxes of airspace.

I am aware that in the UK there are at least four potential errors for
airspace boundaries:

1) Out out date airspace files
2) typographical errors
3) issues with converting from points and widths to boxes
4) issues with straight lines - rhumb lines v great circle routes

I don't know how you create your US airspace files.

I have identified a number of UK airspace boundaries where the
discrepancy on the straight edge of an airspace
Boundary with accurately plotted end points can be significant.

I have identified some errors of upto 400m on boundaries measuring only
100km or so.
If you are looking at boundaries with endpoints further apart then the
straight line errors will be larger.

So from what I read, you may wish to debate the niceties of what is a
straight line.

Or preferably, just applaud an excellent flight.

Rory


Subject: IMPORTANT- Seeyou V's Strepla and airspace violations.
Author: Marc Ramsey
Date/Time: 18:20 10 September 2006

The airspace problem is more complicated, we're talking a hundred or so

feet either side of the boundary. Given that there are not two, but
actually three pieces of software involved (SeeYou, Strepla, and
WinPilot), minor calculation errors in any of them could put one on
either side of the boundary. I have no desire to put any energy into
figuring out how the fixes in the IGC file relate to the published
airspace boundary, but perhaps someone else does.

wrote:

Lastly is a 100ft or 1000ft violation any different. it is still an
incursion either way you look at it.

No, it isn't. You can't ignore the accuracy of the measuring device.
For a glider with a cheap altimeter and a cheap GPS, 1-200 feet is well
within the possible measurement error at 18K. 1000 feet isn't (usually).

Read some of the stuff to do with RVSM.

The calibration of the logger and altimeter doesn't take into account
the position error when connected to the glider static source. Then
there are the gliders where the static source is just cockpit pressure.
Even if it's accurate in the test chamber, God knows what an altimeter
or logger will say when screwed in the glider.

Dick Johnson's reports always begin with calibration of the pitot-static
system and he has been scathing about the inaccuracy of some gliders -
mostly due to poor positioning of static sources. He's found errors of
7 knots in airspeed readings. Imagine what means for altimeter accuracy.

How is a pilot to KNOW that his logger is recording 18,200ft when his
altimeter says 17,900ft? On the OLC, YOU see what the logger said. The
pilot only knew what his altimeter said. When he lands, he has no
evidence that his altimeter never saw a violation.

These are gliders with no natural vibration. Next time you're climbing
through 17,500 feet, tap your altimeter. Ten bucks says it will jump
more than 100 feet if it's more than 5 minutes since your last tap. If
you get to 25,000, it'll jump nearly 200 feet.

Set your altimeter sub-scale to quarter of an inch above QNH, tap it,
then wind it back to QNH and read the altimeter without tapping. Do it
again but start from quarter of an inch below QNH. Even at near sea
level altitudes, many gliders will differ by 50-100ft AT THE SAME QNH!

You've got a lot more faith in cheap instruments than I have, Al.

GC

Graeme Cant schrieb:

Lastly is a 100ft or 1000ft violation any different. it is still an
incursion either way you look at it.

No, it isn't. You can't ignore the accuracy of the measuring device.

Yes, it is. If your devices are inaccurate, then it's your
responsibility to add some extra safety margin. Simple as that.

Stefan

I find it absolutely fascinating that pilots that will cheerfully
exceed the posted speed limit (along with just about everybody else, of
course) during the drive to the gliderport will then pontificate about
minuscule infringements of vertical and lateral airspace bounderies.

Uh, guys, these are regulations, not laws of physics! You are safer at
18,300' looking out the window than at 17,700' staring at the
altimeter!

Of course, I now fully expect to be viciously flamed, but what the
hell, it's monday and it's raining....

Kirk
66

At 13:24 11 September 2006, Kirk.Stant wrote:
I find it absolutely fascinating that pilots that will
cheerfully
exceed the posted speed limit (along with just about
everybody else, of
course) during the drive to the gliderport will then
pontificate about
minuscule infringements of vertical and lateral airspace
bounderies.

Uh, guys, these are regulations, not laws of physics!
You are safer at
18,300' looking out the window than at 17,700' staring
at the
altimeter!

Of course, I now fully expect to be viciously flamed,
but what the
hell, it's monday and it's raining....

Kirk
66

I have pondered over this in detail after having read
most of the threads in RAS and here. And I am still
undecided.

When OLC started it was purely fun and easy, now it
has become 'the' entity for showing not only the world
but even more importantly your local flying buddies
your acheivements. For years I flew in relative obscurity
with only a few people knowing what I did, where and
how fast I went. Now with posting to OLC everyone with
any interest in soaring knows.

The question for me now becomes; Do I have a responsibility
to my flying buddies to protect their right to fly
and not bring unwanted attention of allegded violations
of the FAR's to our club and local flying area. To
that question I have to say yes.

On the other hand it makes me angry that a once fun
and purely innocent OLC (after all we are in it for
the money and chics) has been takin over by the aviation's
version of the 'Moral Majority' and turned into the
McCarthyism of everybody looking suspicously at each
others flights and airing those suspiscions publicly
in the name of protecting their right to fly. It just
smacks of Orwell's 1984 'big brother is watching'.
Read Soarpoint's post on RAS.

Then again we don't have to post our flights that violate
the FAR's! So now you see why I am so undecided

Hi,

I haven't followed this tread closely, but I think I need to point out that
both SeeYou and StrePla automatically offset the altitudes displayed to
account for pressure changes using the takeoff elevation. The feature can
be disabled, but you must know that it exists and know how to disable it. I
am a state soaring record keeper and I recently verified that the altitudes
in SeeYou were offset by using the takeoff elevation to "calibrate" the
pressure altitude data from the logger. I wanted to view the raw data so I
looked in the IGC file and I also was able to disable the calibration
feature in SeeYou and see the raw data in the SeeYou analysis. It works
great, but you have to know it exists.

Good Soaring,

Paul Remde
Cumulus Soaring, Inc.
http://www.cumulus-soaring.com

wrote in message
oups.com...
This boils down to software.

One shows violations the other doesn't.

You have Seeyou or Strepla?
If not don't comment!!


Mark Dickson wrote:
I can't believe I'm reading this. This is one one
of the most embarrassing things I've read on a gliding
forum. Al, you're a disgrace.

At 17:42 10 September 2006, wrote:
OK in order to sort a dispute that is running between
Ramy and myself.

I have Strepla which shows minor airspace and altitude
violations which
Seeyou does not.

FYI. Ramy's Logger Calibration report shows a +169ft
error at 18000ft.

The flight in question is this one here .
http://tinyurl.com/fe2k8

I ask users of both software to look at this flight
and report their
findings.

If this exercise highlights a bug in Strepla I owe
Ramy an apology.

Thanks

Al

This reminds me of Lord of the Flies.

We spend all this time worrying about hypothetical situations where the
FAA uses our IGC files to rain on our parade, when all the time the
true enemy was ourselves.

"JS" wrote in message
oups.com...

Marc Ramsey wrote:

Anal nit-picking has now become the most important aspect of soaring,
apparently, thanks to the SSA-OLC collaboration...

Marc

Total Madness. (Which is a great compilation of ska tunes from a band
that could teach us all to lighten up.)
Jim


But what if he went "One Step Beyond"!?!?!?

I agree with Doug. But to set things straight before we stopping this
nonsense, here is a quote from the email I received from the SSA-OLC
committe:

"Ramy, I don't see any problem with the Restricted airspace. You cut it
pretty close, but the track is not inside at any point. Even if it was,
we would need to consider that the GPS has an error budget."

Ramy


Doug Haluza wrote:
This thread is completely out of control, and I want to see this
nonsense stop. If someone has a legitamate issue, contact the SSA
committee by email at olcatssadotorg with the specifics, and we
will look into it. Throwing wild accusations around on a public forum
reflects badly on you and on the group. And I do not want to
participate in this circus.

Ramy wrote:
Doug, I would like to ask you to check my 6/24 flight and determine
officially if I violated any restricted airspace. Both according to the
winpilot airspace data I use during flight and according to SeeYou the
closest I got was 550m. My trace also clearly show my effort to go
around the restricted airspaces.Please post the results to RAS as soon
as possible as I want to put an end to this circus. If you determine
that I busted a restricted airspace you have my permission to remove
this flight completly. I will not contest it, and will simply draw my
own conclusion about the faith I have in the system.

Thanks,

Ramy

Stefan wrote:
Graeme Cant schrieb:

Lastly is a 100ft or 1000ft violation any different. it is still an
incursion either way you look at it.

No, it isn't. You can't ignore the accuracy of the measuring device.

Yes, it is. If your devices are inaccurate, then it's your
responsibility to add some extra safety margin. Simple as that.

Stefan

Rubbish. When it comes to altitude for ATC purposes - and that's what
the 18k limit is for - the reading on your altimeter is what counts.
Provided it's a legal instrument maintained properly, you fly to the
indications of your altimeter. Asking whether this is "accurate" is
irrelevant and meaningless. If you're told to maintain 18k in a powered
aircraft, what "safety margin" should you allow? Fly at 17750? Fly at
18400? Nonsense!

The OLC's problems arise because the legal device Ramy HAS to use when
he might bust a rule is the altimeter, not the logger. But when he
lands only the LOGGER figure is still there. Ramy was only illegal
though, if he flew over 18k on his ALTIMETER.

The madness of all of this is that the accuracy that Al seems to expect
is not expected by any of the authorities whose rules he claims were
broken. He thinks the whole thing is way more accurate than it is and
way more accurate than any of the real airspace users need it to be.

ATC define en route airways on a radar screen where the defining line is
400 yards wide - with fuzzy edges - and a target takes three sweeps to
cross it!! Al's concept that an airspace boundary is a precision line
in space accurately marked like the painted centreline on a road is
laughable.

So is the idea that a glider's position is measured to an inch by a $200
GPS receiver. Ramy may be 400yards outside a boundary on ATC's scope
but his GPS logger may show him as inside the rhumb line between the
coordinates defining the boundary. Or maybe inside the rhumb line but
outside the Great Circle. Was he wrong or right? If the coordinates
are 100 miles apart, the difference between rhumb line and Great Circle
could be a mile or more and what ATC's scope lines show is probably
neither. He's expected to measure his position by - at best - VOR
radial and DME, not GPS, so there's probably an uncertainty circle about
2 miles in diameter!

What Al wants to do with logger barometric readings and GPS positions is
needed by no other airspace users and the system doesn't work to that
level of accuracy.

GC