IMPORTANT- Seeyou V's Strepla and airspace violations.

wrote:
OK in order to sort a dispute that is running between Ramy and myself.

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

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.

Strepla is clearly wrong on the altitude, as I told you privately, I
carefully extracted all of the pressure altitude data from the IGC file,
and there wasn't a single fix that exceeded 18,000 feet, once corrected
for the *landing* altitude and calibration error. I invite you to do
the same.

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.

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

I believe you owe Ramy an apology in any case, it is ridiculous to be
wasting time on violations that don't amount to much more than 100 feet,
at worst.

Marc

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

"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"!?!?!?

Marc you TOLD me that you had reviewed please pass along the file or
other data that supports your claim.

Enough hearsay as there is obviously a software error here on either
Seeyou or Strepla.

Lastly is a 100ft or 1000ft violation any different. it is still an
incursion either way you look at it.
I would be curious to here that form contest scorers.

I remember a case a while back a pilot was allowed a turnpoint in a
contest even though the GPS point was not in the turn zone. It was
later protested out and his flight devalued.

Thanks

Al


Marc Ramsey wrote:
wrote:
OK in order to sort a dispute that is running between Ramy and myself.

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

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.

Strepla is clearly wrong on the altitude, as I told you privately, I
carefully extracted all of the pressure altitude data from the IGC file,
and there wasn't a single fix that exceeded 18,000 feet, once corrected
for the *landing* altitude and calibration error. I invite you to do
the same.

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.

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

I believe you owe Ramy an apology in any case, it is ridiculous to be
wasting time on violations that don't amount to much more than 100 feet,
at worst.

Marc

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

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