Re: Subscription to NASD CD-ROM (was: embedded ...)

[Bob_Deep <bobd@cssgroup.com>]

Andy Ross wrote:
> 
> Brian Lloyd wrote:
> > >I'd bet, if we wrote a converter from the Fed data to the Jeppeson
> > >format, you would have very few differances.
> >
> > Regardless of what I have said, if that were so, I suspect that the GPS
> > manufacturers would opt for the less expensive FAA data.  They don't and
> > that is universal.  Why do *ALL* the manufacturers use Jepp data?  There
> > must be a reason.
> 
> Thank you, exhibit A. :)
> 
> I think you just showed us the reason:  Jepp data is _perceived_ as more
> accurate (because everybody uses it, of course).  Since the database
> cost is a small fraction of the unit cost for a GPS receiver, and
> especially since the maintenance cost of upgrades isn't the problem of
> the manufacturer (the user has to pay for them), the manufacturers just
> use Jepp data by default and write off the extra cost as "advertising".
> 
> Mind you, _I_ haven't looked at the data for discrepancies, but I'd be
> a little worried if the government data was actually _wrong_.  It's the
> same data that goes into the NOS charts and approach plates, isn't it?
> Since NOS users aren't flying into the ground any more than Jepp folks
> (I presume -- if this isn't true I smell a HUGE class action lawsuit
> brewing), I argue that this is an existance proof that the Jeppesson
> database is no better than the FAA one.

I thought that the Jeppeson approach plates, though different looking
than the NOS ones, where functionally equivalent.  If memory serves,
they added a bit more information to their approach plates, but nothing
you could not figure out from the NOS charts you should have in the
plane anyway.

I also believe that it's the FAA that approves ALL instrument
approaches, going so far as to actually fly them in a specially equipped
aircraft to verify that everything works together right.  Does Jeppeson
verify approaches?  Do they go out and spend the money to fly them?  No
they don't.  

They got their start by making approach plates that went into binders so
they where easier to open.  The paperback NOS plates got difficult to
manage in-flight and if you ever dropped your NOS book, it was going to
take some time to look up the approach plate again.  Of course you could
just rip out the plate from the book, but you could not put it back. 
Jeppeson just started to print the changed plates, not entire books, and
gave you a neat binder to put them in that made it easy to get them in
and out...  It went from there to this "electronic" format.  This type
of data did not become popular until we started seeing LORAN units, GPS
and Internal Nav stuff, but Jeppeson was there when the air carriers
started looking for this data in a consistent format, so their format
got adopted by the "big boys" long before the average Joe could afford a
Loran or GPS unit for their very own, we just where along for the ride.

It's the government data that is the "legal" data.  You must fly your
Instrument approach using the government verified data on the current
approach plate with any NOTAMs taken into account, or it's against the
rules.  If Jeppeson takes liberties with the data, and "fixes" something
in the government's certified data, then you cannot legally use their
approach plate.  Now if they ADD information to the government's data,
that's OK.. They just cannot change the certified approaches in any way.

After thinking about it, I believe I know what Jeppeson basically does. 
They provide a consistent input format.   A Jeppeson database is a
standard well known format, that will not change.  The government may
change their data format and different countries may have vastly
different data formats, ranging from paper maps to databases.

Jeppeson also crosses other government sources of information and adds
this to their data.  Thus the "additions" to the standard approach
plates.  I seem to remember where they added the local center's comm
frequency so if you miss the approach you will have it written some
where and some other "nice but not necessary" information.

This is all for "in the states" data.  Outside of the states, Jeppeson
does have some good data, and again in the same format.  Jeppeson is
selling data in a consistent format from various government sources.  I
seriously doubt they are making any modifications to the data that they
receive from the various governments around the world.

What does this mean for us?

Well, I'm basicly saying that if we can deliver a means for pilots to
print or view approach plates let's say.  Then if we have the certified
data from the fed, you should be able to legaly use this data to fly by
in IFR conditions, assuming we can faithfuly render the data.  This will
eliminate the need to keep a bookcase of NOS charts in the right seat,
and you can simply print all possible charts over your intended route,
or for the area you normally fly.  If you have a computer on board, then
you can load it with the data for the region you could possibly ever
fly, and have a ready referance of flyable charts just a few keystrokes
away, should you get in a spot with the weather closing in.

I suspect that the FAA would be VERY picky about software that displayed
and printed such information, and would want to certify such software
before allowing it to be used for real IFR operations.  But, I also
suspect that the NOS folks would be VERY interasted in the software, and
perhaps they would sponcer a FAA Review and publish "approved" versions
of the open source.

-- 
      -=  Bob =-
Hey.. This is my mail and I charge for SPAM I receive...
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