A little fun from France (approach procedure)

On Tue, 23 Nov 2004 21:44:27 +0000 (UTC),
(Paul Tomblin) wrote:

It's a little weird that they don't depict the ILS on the chart the way
they do on NOS charts, though, don't you think? Until I read the "ILS" on
the minimum section, I thought the "025 degree" course after 5.4 AJO meant
a 025 bearing to and then from CT.


LOL, I just saw that too. Initially I thought it was an NDB approach.

z

"Paul Tomblin" wrote in message
...

http://faris.nerim.net/LFKJ.JPG

I especially like the fact that while altitudes are in feet (and speeds in
knots), RVRs and visibility figures are in metres.

That's standard ICAO (blue table), used almost everywhere outside N America,
except the old eastern block, some of whom use metres for vertical level.
Visibilities and RVRs are all quoted in metres in METARs.

What I find weird about that LFKJ approach is the minimum RVR of 1200 m with
a DH of 1050 ft above the threshold. Thus the decision point is 3 miles
out: they must have some pretty bright boats moored on the approach...

BTW, you can access all the French IAPs in PDF form at

http://www.sia.aviation-civile.gouv..../IAC/index.htm

Some of the Paris ones are complex in a rather different way -- three plates
required for one approach.

Julian Scarfe

"Julian Scarfe" wrote in message
...
....snip...
BTW, you can access all the French IAPs in PDF form at

http://www.sia.aviation-civile.gouv..../IAC/index.htm



Superior website!

One-stop online shopping (free) for all the instrument and visual approach
plates, airport diagrams, local procedure information, all the
flight-directory-type information, enroute low and high level charts,
navaids, regulations, and much more.

NAV-Canada and Transport Canada: please take a hint.

As to subtleties of procedures, the frogs have chosen to make one chart
needlessly complex to save paper. Jeppesen charts that procedure (three
procedures actually) on three separate charts.

Lots of human-factors opportunity for error when using unfamilar charts to fly
instrument procedures.

G Farris wrote:

We're always complaining about the subtleties of this or that procedure, so I
thought I'd throw in this one from Corsica. I particularly like the missed
approach - in IMC at night.

http://faris.nerim.net/LFKJ.JPG

G Faris

Y'All,
I can recall at early visit to SFBay Tracon early in my career that
the radar scope showed all the freeway traffic as well as the few aircraft
aloft. Very difficult to interpret until the French came up with a way,
electronically to remove all the slow moving targets. Initially it was
possible for an aircraft flying an arc around the antenna at a specific
distance to disappear from the scope. Don't know if problem has been
solved. Anyone know?

Gene Whitt

wrote in message ...
As to subtleties of procedures, the frogs have chosen to make one chart
needlessly complex to save paper. Jeppesen charts that procedure (three
procedures actually) on three separate charts.

Lots of human-factors opportunity for error when using unfamilar charts to
fly
instrument procedures.

G Farris wrote:

We're always complaining about the subtleties of this or that procedure,
so I
thought I'd throw in this one from Corsica. I particularly like the
missed
approach - in IMC at night.

http://faris.nerim.net/LFKJ.JPG

G Faris

In a previous article, "Gene Whitt" said:
electronically to remove all the slow moving targets. Initially it was
possible for an aircraft flying an arc around the antenna at a specific
distance to disappear from the scope. Don't know if problem has been
solved. Anyone know?

I would think that the speed gate would only apply to primary targets, not
transponders, don't you think? If it weren't, it seems that it would be a
mere matter of programming to fix it.

I'm told that fighter planes use the same technique to evade enemy radar
guided missiles, flying an arc around the in-coming missile (although they
use terminology like "putting your z-pole on the target" or something). I
believe fancier radars can apply the speed gate to your speed even if it's
parallel to the antenna, even if it's primary only, but I don't believe
either ATC radar (which is, after all, designed to track cooperative
targets) or older missiles like Sparrow have that capability. I wouldn't
be surprised if AMRAAM and other newer missiles do.

--
Paul Tomblin http://xcski.com/blogs/pt/
I am not a vegetarian because I love animals; I am a vegetarian
because I hate plants. -- A. Whitney Brown

There is a particular piece of digital signal processing used in radar (or at
least, it was in use when I was an undergraduate electrical engineering student
25 years ago) called the "chirp Z-transform." The singularities in the function
are called the "poles," after an analogue computing technique used in the 1930s
for finding those points. It may be that pilots are taught to figure out the
poles in the particular function in use and to fly a pattern that corresponded
to the singularity, or perhaps their onboard computers do this.

Just a guess. Perhaps there are some more current EEs reading who can fill in?

David

Paul Tomblin wrote:

I'm told that fighter planes use the same technique to evade enemy radar
guided missiles, flying an arc around the in-coming missile (although they
use terminology like "putting your z-pole on the target" or something). I
believe fancier radars can apply the speed gate to your speed even if it's
parallel to the antenna, even if it's primary only, but I don't believe
either ATC radar (which is, after all, designed to track cooperative
targets) or older missiles like Sparrow have that capability. I wouldn't
be surprised if AMRAAM and other newer missiles do.

David Kazdan wrote:
The singularities in the function are called the "poles," after an
analogue computing technique used in the 1930s for finding those
points.

I thought they were called poles because if you made a surface plot of
z(x,y), it looked like a big tent, and the sigularities were like the
spikes where the tent poles stuck through.

I'm sure I'm dating myself, but I actually used analog computers in
college. The EE lab had a bunch of them for control systems work. It
was kind of fun programing systems of differential equations by plugging
patch cords into a big plugboard and watching the answer get drawn on a
scope. I wouldn't be surprised if the aerodynamics of most of the light
planes we fly today were worked out on exactly such machines.

Hmmmm. Just did some googling. The more I look at the picture, the
more I'm convinced it was a TR-20 we must have been using. We also had
a TR-48 in the lab, but most students didn't get to use that.

http://dcoward.best.vwh.net/analog/eai.htm

Disappearance of the primary target when it has no radial velocity relative
to the radar antenna is due to zero range rate and zero doppler. Radar
signal processing usually eliminates returns with very low dopplers to
reduce ground clutter. Radar data processing frequently eliminates targets
that show zero range rate even though they may have a doppler signature.
Flying an arc relative to an enemy radar is one technique sometimes employed
to reduce detectability, but it has to fit in with other tactics. As for
the "z-pole on the target", I have never heard that expression, but my best
guess is that it refers to the z-axis of a 3-dimensional Cartesian
coordinate system, which would be the vertical axis. Flying a circular
pathway in the x-y plane relative to the origin of this coordinate system,
and positioning the origin at the radar (z-axis vertical through the radar)
would result in zero doppler of the main body return.

Stan

"David Kazdan" wrote in message
...
There is a particular piece of digital signal processing used in radar (or
at
least, it was in use when I was an undergraduate electrical engineering
student
25 years ago) called the "chirp Z-transform." The singularities in the
function
are called the "poles," after an analogue computing technique used in the
1930s
for finding those points. It may be that pilots are taught to figure out
the
poles in the particular function in use and to fly a pattern that
corresponded
to the singularity, or perhaps their onboard computers do this.

Just a guess. Perhaps there are some more current EEs reading who can
fill in?

David

Paul Tomblin wrote:

I'm told that fighter planes use the same technique to evade enemy radar
guided missiles, flying an arc around the in-coming missile (although
they
use terminology like "putting your z-pole on the target" or something).
I
believe fancier radars can apply the speed gate to your speed even if
it's
parallel to the antenna, even if it's primary only, but I don't believe
either ATC radar (which is, after all, designed to track cooperative
targets) or older missiles like Sparrow have that capability. I wouldn't
be surprised if AMRAAM and other newer missiles do.