[jhb_airlines] Re: PMDG 737NG

  • From: "Bones" <bones@xxxxxxx>
  • To: <jhb_airlines@xxxxxxxxxxxxx>
  • Date: Mon, 13 Sep 2004 15:21:14 +0100

I must admit that I now use Richard Stefan's AIRAC data to update both
the 737TNG and FSNav databases although this requires separate
downloads. http://www.navdata.at/php/airac/airac.php

As to collecting flight plan data we still run up against the same
problem - the European route structure is changing too much to rely on
data more than a month or two old. It will settle down eventually but we
must accept that our timing is unfortunate as it comes at the most
radical restructuring of European airspace in the last 50 years. This
has been going on for four years now (they tend to make the major airway
changes only during the winter months) and it is dynamic in the sense
that computer analysis of the initial changes tends to show traffic
patterns that dictate the later changes.

In the past we had a good document in ATC which showed the "accepted"
routes from the UK to almost any global destination. This was a normal
publication until around 1997 when airspace changes started to increase
and it was realised that it needed continual amendment. In the end it
became similar to the Air Pilot with monthly updates. We used it for all
our flight planning address data. I have looked for this document on the
CAA site but it no longer exists - probably because all flight plan
route data is now in the central European computer system and national
publications are obsolete.

I'm checking the website of IFPS (Integrated Flightplan Processing
System) right now in the hope that the current route data is now
available online but I end up down some blind alleys. At the moment I
have found myself on the CFMU (Central Flow Management Unit) site and
this is quite interesting because it is the tactical side of IFPS. The
current tactical situation can be found at
http://www.cfmu.eurocontrol.be/home/index.html if you select Operations
and then Public Applications (including strong wind warning for EBBR
Brussels Airport)..

If you go to this page you will see several ATFM (Air Traffic Flow
Management) options on the left menu panel and I will try and explain
what these are. Under Messages there are options for:
ANM (Current)
ANM (Next)
CRAM (Current)
CRAM (Next)
Route Availability

AIM (ATFM Information Message) is for current tactical messages and some
long term older messages.
ANM (Current) is a list of the restrictions for the current day. This is
dynamic and changes are added/amended as the day develops. I will
sidetrack slightly by explaining how this system works.

Most airlines file their flight plans in advance for a whole season and
these are stored on the IFPS computer. The system can therefore look at
any particular day and predict the traffic flow for the period -
including the areas where traffic is likely to overload. Add to this the
flight plans for private and charter aircraft plus any scheduled flights
not in the season's listing and the computer predictions begin to change
as these plans come in. The CFMU is therefore dynamically looking at
constantly evolving airspace utilisation and predicting traffic hot
spots. Add to this some additional factors - like strong winds reducing
landing rates or airport closures owing to accidents or weather - and
you can see that CFMU is continually updating their situation awareness
on European traffic flow.

The ANM (ATFM Notification message) is a list of these bottlenecks. The
first two on the list today are about reduced landing rates at Brussels
owing to strong winds and single runway operations. The rest are
somewhat harder to fathom especially those relating to airway sectors. A
copy of current ANM's are sent to every airport in Europe.

To some extent these ANM's are totally meaningless to the average pilot
or ATC unit. They are simply a list of congestion areas for the current
day and should really be put on the "nice to know but rather
superfluous" list. The reason why I say this is because CFMU's second
task is to organise the traffic to reduce these delays. The two most
common restrictions are allocating slot times or giving aircraft revised
routes to fly. Most pilots don't look at the ANM's - all they want to
know is what their slot time is or whether they have been rerouted.

ANM (Next) is for tomorrow's restrictions and is usually published
around 1700.

CRAM (Current) is a list of the Conditional Airways active for today.
These are either existing airways in which the published rules have
altered (e.g. using a one way airway as two way) or temporary airways
created to ease traffic congestion.

Route Availability Document takes you to a separate web site and,
although interesting, it doesn't provide what it says. In fact it should
be called "route unavailability document" as it provides you with a list
of airways that are restricted in use or not available.

Although all the above information is interesting it still doesn't
provide us with what we are looking for without a lot of sifting and
digging around. Effectively all the above data could be pulled together
to show a table of currently available air routes just by entering
departure and destination airfields and I am still looking for this.. It
will be in there somewhere..


> -----Original Message-----
> From: jhb_airlines-bounce@xxxxxxxxxxxxx 
> [mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Kevin Townsend
> Sent: 13 September 2004 12:47
> To: jhb_airlines@xxxxxxxxxxxxx
> Subject: [jhb_airlines] Re: PMDG 737NG
> Tom
> I will have a look, but I am using Airac for my PMDG and as 
> there are many 
> anomalies between the FSNav Database and this - I have been 
> constructing 
> flight plans by hand.
> Using FSNav I input Departure and Arrival Airports Codes using the Id 
> (ticked) Inputline on the Map Page. I then follow the mostly 
> direct line 
> using Navaids along the way. I then Print this route, 
> including SID/Star 
> alternates and use this as a routing as would be provided for any 
> commercial flight. This would include Initial clearance and routing 
> altitudes. Standard routes were published on the UK AIS.
> Bones assures me that this is the way that airlines work 
> these days, as 
> routing is done by computer, based on traffic density, and 
> the shortest 
> (most direct) routes go on a first come first served basis.
> I include some comment from him below...
> The airway system in Europe is effectively dynamic nowadays 
> rather than the static system of old. Pilots still file 
> flight plans with the suggested IFPS routes in them, but if 
> such routes are congested IFPS will automatically reroute to 
> avoid delays and send a revised flight plan back to the 
> pilot. We can't mimic this in FS so the best option is to put 
> down the published standard routes. Oddly enough I can't see 
> these on the UK AIS site any more - I'll have to dig around 
> and see where they have gone..
> Maybe we should find a place to collect these?
> Regards
> Kev
> At 11:40 9/13/2004, you wrote:
> >kevin would you send some more flight plans
> >for the 737 fmc
> >Tom

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