HDTenEightyP/NetNews huggingface dataset:
From: barnett@convex.com (Paul Barnett)
Subject: Re: DH determination (was Re: GPS and IFR Approaches)
Date: Tue, 5 Jan 1993 21:41:13 GMT
Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

In <1993Jan5.164308.711@oakhill.sps.mot.com> mpaton@oakhill.sps.mot.com (Michael J Paton) writes:

>None of this stuff appears to me to have sufficient accuracy, precision and
>availability to serve as backup except in an emergency. A DME may very well not
>be available, or may not be usable in the location you want it, or may go out
>or saturate with excess interrogations when you want it. (eg our local 
>Austin, TX DME has a request made in the A/FD that you turn your DME off
>while on the ground. I don't know anybody who does this). The DME displayed
>precision appears to be +- 0.1nm which translates to +- 30 ft assuming a 
>3 degree glideslope and my math being correct, which seems like enough.
>Seems may well not be good enough.

A DME is required only if the approach calls for it (i.e., VOR/DME
whatever).  Otherwise, it is only a cross-check, as you point out.
One place that it is legit to use it for a navigation fix is at the
outer marker (in coordination with the localizer), if the distance is
depicted on the approach plate.  I don't know what a depicted distance
at the middle marker is good for, other than to warn me that I am near
the DH, and that's all the middle marker is good for anyway. 

If the DME is inoperative or suddenly goes flaky, then you have to use
a alternate method.  However, I wonder: you used to increase the DH 50
feet if you discover your marker beacon receiver is broken, or the MM
is NOTAM'ed OTS.  If a DME fix was provided, was that still true?  I
think it's academic, since the MM requirement has recently (or will
soon be) lifted.

>I believe some European air regulating bodies believe the altimeter is
>enough of a problem to require 2 of them for IFR flight. Perhaps someone
>can explain their rationale for this requirement, and if separate static
>systems are required for the 2 altimeters.

>I'm not sure 2 would make me much happier or more secure. I'm usually in
>something of a quandry on a local VOR/DME approach when my 2 VOR's which are
>both in tolerance say different (but in tolerance things). I know I'm supposed
>to pick one and use it, but I keep trying to remember which one would be best.

There is a old saying that is funny on it's own, but it seems to apply
to dual altimeters, VORs, etc: "Man with one watch knows what time it
is, but man with two watches is never sure."
--
Paul Barnett
MPP OS Development     (214)-497-4846
Convex Computer Corp.  Richardson, TX
Newsgroups: rec.aviation.ifr
From: mikec@ginger.lcs.mit.edu (Mike Ciholas)
Subject: Re: GPS vs DGPS info needed
Organization: MIT Laboratory for Computer Science
Date: Mon, 11 Jan 1993 15:35:39 GMT

In article <447.185.uupcb@ssr.com>
	dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin)  writes:
>GPS receivers compute their position by figuring their distance from
>several satellites, based on information continually broadcast by those
>satellites.  The military, which "owns and operates" the system, puts
>some bogus information in the transmission, to intentionally reduce the
>accuracy of the system and make it less usable by the "bad guys."
>(Called SA, for Selective Availability)
>
>DGPS is a system which corrects for those errors.
>[...]

While DGPS does nullify the SA errors, its primary value is to improve
the basic accuracy of the positioning information.  Even if SA where
turned off permanently, straight GPS would not be good enough for
precision approaches, whereas GPS with SA turned on might (most
likely) be adequate for non-precision approaches, and is certainly
accurate enough for enroute navigation.  Thus DGPS is primarily an
approach issue.

There are subtle benefits (besides the accuracy improvement) to DGPS
due to the presence of a ground station that is also monitoring the
satellites.  This can provide very reliable signal integrity
monitoring.

Mike Ciholas
mikec@lcs.mit.edu

Newsgroups: rec.aviation.ifr
From: gary@maestro.mitre.org (Gary Bisaga)
Subject: Re: GPS and IFR Approache
Reply-To: gbisaga@mitre.org
Organization: The Mitre Corporation, McLean Virginia
Date: Thu, 7 Jan 1993 22:17:17 GMT

In article <418.185.uupcb@ssr.com>, dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin)  writes:
|> Perhaps I didn't state it clearly enough.  The available technology is
|> such that there are no blocking issues.  There is lots of work being
|> done to choose specific technology and formulate specs, but the accuracy
|> and integrity issues are all resolvable with current technology.
Actually, I have heard (indirectly) that Jepp says one of the problems
is database accuracy.  They apparently estimate their databases at 10-5
error rate, which is only good enough for non-precision approaches.  And
Jepp is probably as good or better than anybody.  Technology improvements
will certainly take place that will make GPS more accurate, more available,
etc.  Database errors may be another question - we're dealing with humanware
here.  Anybody from Jepp care to make a first-hand comment on what I heard
second-hand?

-- 
Gary Bisaga (gbisaga@mitre.org)
Newsgroups: rec.aviation.ifr
From: philf@xymox.palo-alto.ca.us (Phil Fernandez)
Subject: Re: New VOR approach to Moffett Field
Organization: Jade and Jett Incorporated
Date: Thu, 7 Jan 1993 05:23:48 GMT

In article <87240002@hpcc01.corp.hp.com> mtc@hpcc01.corp.hp.com (Mark Cousins) writes:
>Some years ago I sketched out a VOR 30 approach based off the SJC VOR.  I
>don't have the TERPS but it seemed fairly workable.  The missed was as
>Christophe states:  the standard IFR departure from PAO (right turn heading
>060, maintain 3000, direct SJC VOR and hold).

I've also looked at an approach to PAO, using the Woodside (OSI) VOR.
It turns out that if one flies the Casa Grande, AZ (CGZ) VOR Rwy 5
approach, substituting the OSI VOR for the Stanfield VOR, and
subtracting 1400 feet from the altitudes, it works great as a VOR-A
approach into PAO.  As with Mark, the standard IFR departure route for
PAO would work fine for the missed.

I passed this by a friend who spends a lot of time on Compuserv AVSIG,
and he discussed this approach possibility with the AVSIG resident
TERPS expert.  This guy's opinion was that such an approach from OSI
was perfectly workable for PAO, although it does perhaps have a slight
issue with the TCA and approach corridors used for SFO.

pmf
From: 9227792@ul.ie
Newsgroups: rec.aviation.ifr
Subject: What are the new European regulations?
Date: 4 Jan 93 12:41:25 GMT
Organization: University of Limerick, Ireland


Has anybody heard about the new rules and regulations
that are being brought in Europe this year by the 
aviation governing body,the C.A.A. I think?
Stuff on air law mainly.
Please inform me cause the literature I have is based
on the old rules and I have a few written exams coming up 
in a few months for my PPL.
Newsgroups: rec.aviation.ifr
From: lhe@sics.se (Lars-Henrik Eriksson)
Subject: Re: What are the new European regulations?
Organization: Swedish Institute of Computer Science, Kista
Date: Wed, 6 Jan 1993 21:41:31 GMT

In article <20214.2b483075@ul.ie> 9227792@ul.ie writes:

   Has anybody heard about the new rules and regulations
   that are being brought in Europe this year by the 
   aviation governing body,the C.A.A. I think?
   Stuff on air law mainly.
   Please inform me cause the literature I have is based
   on the old rules and I have a few written exams coming up 
   in a few months for my PPL.

There is an ongoing JAA (Joint Aviation Authorities) program to write
common European regulations. There are already JAA rules about
airworthiness and maintenance in effect. JAA rules for pilots'
licenses (JAR-FCL) are going to come into force this year. The comment
period ended in November last year, and the JAA is right now busy
making sense of the comments.

Once the rules have been decided upon, the JAA member states have
until the end of 1995 to put the rules into force.

The newsgroup eunet.aviation might be more suitable than
rec.aviation.ifr for questions of this kind
--
Lars-Henrik Eriksson                            Internet: lhe@sics.se
Swedish Institute of Computer Science           Phone (intn'l): +46 8 752 15 09
Box 1263                                        Telefon (nat'l): 08 - 752 15 09
S-164 28  KISTA, SWEDEN                         Fax: +46 8 751 72 30
From: mtc@hpcc01.corp.hp.com (Mark Cousins)
Date: Thu, 7 Jan 1993 00:46:28 GMT
Subject: Re: New VOR approach to Moffett Field
Organization: HP General Systems Division
Newsgroups: rec.aviation.ifr

In rec.aviation.ifr, philf@xymox.palo-alto.ca.us (Phil Fernandez) writes:

>While I was trying to get a word in edgewise (on an IFR departure),
>the flight check pilot was explaining to the controller that when the
>Navy departs, the FAA will activate a VOR approach to Moffett for use
>by NASA.  He explained that the VOR approach will use the Oakland VOR
>(OAK) 139 radial to Moffett RWYS 11.

Moffett's runways are 14/32.  It looks indeed like the OAK 139 outbound would
be the FAC to 14L/R -- it aligns with the runway almost perfectly!

Did they mention any approaches to 32L/R?  Most of the time the winds favor
those runways.  Of course, they could use the same radial inbound for a nice
straight-in, although the VOR is some distance away (about 20 nm or so from
the center of Moffett).

I wonder what kind of interference, if any, there is to the VOR 12R and ILS
12R approaches at San Jose . . . including all the
downwind-to-base-to-intercept vectoring that goes on when those approaches are
in use.

Are they going to decommission the PAR and ASR approaches?

Mark
--
Mark Cousins                Hewlett-Packard Co.        mtc@hpsemc.cup.hp.com
HP-UX VAB programs    19055 Pruneridge Ave., MS 46T5
(408) 447-4659             Cupertino, CA  95014          FAX: (408) 447-4364

Newsgroups: rec.aviation.ifr
From: jallred@spdg.com (John Allred)
Subject: Re: New VOR approach to Moffett Field
Organization: Stratos Product Development Group (Seattle)
Distribution: usa
Date: Wed, 6 Jan 1993 23:12:35 GMT

In article <C0G88F.Jpu@taligent.com> cep@taligent.com (Christophe Pettus) writes:
>Moffett doesn't allow GCAs, mainly for liability reasons.  But since the
>VOR approach would be handled by Bay Approach, it's possible.

Odd -- Gray Army Airfield (just south of Seattle) begs people to use
the PAR, lest they lose their certificate to operate the approach.
-- 
Newsgroups: rec.aviation.ifr
From: cep@taligent.com (Christophe Pettus)
Subject: Re: New VOR approach to Moffett Field
Organization: Taligent, a little subsidiary of two really big companies.
Distribution: usa
Date: Wed, 6 Jan 1993 20:14:38 GMT

In article <76FWBYG1@cc.swarthmore.edu> jeremy@cs.swarthmore.edu (Jeremy Brest) writes:
>And how about so those of us without TACAN can shoot the Moffett
>approach and take a straight-in to Palo Alto instead of having to use
>San Jose or Hayward?  Does a non-civilian field allow this sort of
>use?

Moffett doesn't allow GCAs, mainly for liability reasons.  But since the
VOR approach would be handled by Bay Approach, it's possible.
--
-- Christophe

"Bad analogy!  No biscuit!"
Newsgroups: rec.aviation.ifr
From: Robert Noel
Subject: Re: GPS and IFR Approache
Organization: The MITRE Corporation
Date: Thu, 7 Jan 1993 13:00:52 GMT

In article <418.185.uupcb@ssr.com> dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin) 
writes:
>  > .>Talk to anyone that's got a GPS unit in their aircraft now.  I know of
>  > .>several people that have pulled their LORANs in favor of GPS.  That's
>  > .>under real-world, current conditions, without the full constellation of
>  > .>SVs up.  GPS at its worst is better than LORAN at its best.
>  > .>
>
>TN> .present experience of the current GPS used in VFR is not applicable to
>  > .requirements for IFR precision approaches, such as integrity.
>
>Would you agree that GPS is clearly better than LORAN for precision
>approaches?  <~>
>

yea, but so what?  To me, the issue is GPS vs MLS for precision 
approaches not GPS vs VOR, ILS, NDB, PAR, or anything else.


stuff deleted


>Perhaps I didn't state it clearly enough.  The available technology is
>such that there are no blocking issues.  There is lots of work being
>done to choose specific technology and formulate specs, but the accuracy
>and integrity issues are all resolvable with current technology.
>

in your opinion, things are resolvable....I remain skeptical

Bob Noel
my views are my own, not MITRE's
Newsgroups: rec.aviation.ifr
From: jbrown@qdeck.com (Jordan Brown)
Subject: Re: New VOR approach to Moffett Field
Organization: Quarterdeck Office Systems, Santa Monica CA
Distribution: usa
Date: Tue, 05 Jan 1993 04:09:33 GMT

philf@xymox.palo-alto.ca.us (Phil Fernandez) writes:
>I don't know whether this is good news or bad news for the possibility
>of an approach for Palo Alto.  It sure would be nice...

My understanding is that the problem with an approach to PAO is that it
would interfere with SFO final.  At least that's what some controllers
at PAO told me a few years ago.  Moffett is both further away and presumably
would have relatively little traffic.  Geography might also be a factor, since
it's more possible to have an approach perpendicular to SFO final at Moffett
than at PAO.

Remember you need to worry about both the approach path and the missed
approach path...

If you're interested in such things, I would suggest buying a copy of
the TERPS (I got mine from Pan American Navigation), reading it a few times
so you understand it, and getting a large-scale topo map (USGS 7.5' for
instance) to draw the approach on.  Approaches are HUGE; I drew a VOR
approach to Whiteman (in the San Fernando Valley down here in Los Angeles)
and it covered most of the Valley.  (Looked like it'd work, too, with about
a 600' HAA MDA as I recall.  Not bad when you have a 300' hill next to the
airport.  A NORDO approach would shut down Burbank because of the missed
approach area, but a supervisor at Burbank TRACON told me "none of our
missed approaches really work anyway, we'd have to just clear the airspace".)

(I think Moffett already has a TACAN approach; why do they need a VOR
approach?)
Newsgroups: rec.aviation.ifr
From: greg@bronze.ucs.indiana.edu (Gregory R. TRAVIS)
Subject: Ghost VOR (was Re: Interesting Navaid: ANDREW NDB)
Organization: Indiana University
Date: Wed, 6 Jan 1993 19:32:38 GMT

Speaking of all these new navaids, etc...

Coming back from Roanoke, VA last Saturday, we spied a VOR atop a
mountain.  No big deal, but the VOR is not charted on any approach
plates in the area nor on any enroute charts.

The VOR is located about 1/2 way between the Roanoke VOR (ROA) and the
White Sulpher Springs VOR (SSU).  At first I assumed it WAS SSU and that we
were making good time (we were VFR), but the LapMap didn't agree.  Checking
the frequency and the radials as we passed over it, it was indeed not SSU.

Anyone know the history of this guy?  It is a not-yet-operational
VOR, or one that's no longer in service?

Locals can find the VOR - it's on top of a ridge right by the CASTE 
intersection (ROA 321 radial) just southeast of the town of Paint Bank.

Is it possible that it was a TACAN-only station?  I doubt it, as it's
also not depicted on my TPC charts and it looks JUST like a VOR station.
Don't know what a TACAN-only station looks like.

greg



-- 
Gregory Reed Travis					D P S I
	
Data Parallel Systems Incorporated	greg@cica.indiana.edu
From: randy@khan.gatech.edu (Randal T. Abler)
Newsgroups: rec.aviation.ifr
Subject: Re: Interesting Navaid:  ANDREW NDB
Date: 6 Jan 93 19:47:47 GMT
Organization: CERL-EE, Georgia Institue of Technology

In article <1if8ikINN16n@hp-col.col.hp.com> davea@col.hp.com (Dave Allen) writes:
>rkaplan@netcom.com (Richard Kaplan) writes:
>> I was amused by the recent addition of ANDREW NDB ...
>> Why replace a VOR with an NDB?
>
>An NDB can be set up and tested much quicker than a VOR. They must be short
>on VOR's anyway. 
>And now the Nashville VOR is down or lots of airways are unusable ...

Nashville VOR is on the airport, which is currently undergoing a lot of
construction on runways & taxiways.  I believe this is the cause of the
Nashville VOR NOTAMS.


-- 
Randal  Abler   	randy@cerl.gatech.edu		 
CERL/EE Georgia Tech     
Newsgroups: rec.aviation.ifr
From: jcmorris@mwunix.mitre.org (Joe Morris)
Subject: Re: GPS and IFR Approache
Organization: The MITRE Corporation
Date: Thu, 7 Jan 1993 17:54:04 GMT

dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin)  writes:

> [Ye Olde GPS-vs-everything discussion]

>KK> .It is also my understanding, and someone can correct ME if I'm wrong,
>  > .that the 200' DH for CAT I approaches includes a possible 75' error
>  > .in the altimeter.  There is that much safety margin, provided the
>  > .approach is flown properly (on or above the GS, etc.).

>A properly designed approach takes into account all sorts of
>inaccuracies, including altimeter error, and provides adequate clearance
>for the approach.

>Missing a DH when flying an ILS is actually safer than missing an MDA on
>a non-precision approach.  Even in zero-zero conditions, you could fly
>the ILS to the ground, and as long as you kept the needles centered,
>you'd be in protected airspace.  With a non-precision approach no such
>assurance is available.

This last would be true if, and only if, you can validly assume that
the entire system, both ground and airborne, is working with no error
on the unsafe side, and the radio signal is similarly being propagated
on a linear path.  This is not a reasonable assumption, which is one
reason that CAT II and III approaches use a radar altimeter to provide
the pilot with absolute altitude information.

Look at the number of approaches where there is a restriction against
using a coupled approach below DH.  I suspect that there are concerns
at those facilities about scolloping of the signals due to local 
conditions; at TYS the controllers used to claim that they could see 
airplanes on coupled approaches to 4L make a visible deviation when
a train passed through the approach lights at the same time.

Sure, it will work -- most of the time.  And on my CFII checkride 
(ye gods...almost 20 years ago) the FAA examiner put me through a
zero-zero approach.  (Actually, *he* wanted to demonstrate it after
we exchanged a little BS on the subject.  It wasn't a part of the formal
checkride, and Lonnie Thurston was a genuine "character" in any case.
A nice guy, even if he did work at the FSDO... R.I.P.)

Joe Morris
From: ewv@craycos.com (Eric Varsanyi)
Newsgroups: rec.aviation.ifr
Subject: Re: GPS vs DGPS info needed
Keywords: DGPS, GPS
Date: 11 Jan 93 23:32:20 GMT
Distribution: usa
Organization: Cray Computer Corporation

In article <31490@nntp_server.ems.cdc.com> khubbard@ems.cdc.com writes:
>Could someone give me some info on DGPS, and contract it to plain GPS.  Is DGPS
>that much better than GPS? Does it require additional ground equipment? I have

You can call the GPSIC (GPS information center) run by the Coast Guard. They
have a bulletin board with papers on DGPS and a number of other interesting
things posted. They also have current ephermis data for all active SV's.

Here is the info I have on the GPSIC:
>the Coast
> Guard operates the GPS information center (GPSIC) to provide the public with
> current information on GPS.  Services available include:
>    A. GPS current status recorded voice announcement: phone# (703) 866-3826
>    B. Broadcasts from WWV, Ft. Collins, CO at 14 to 15 minutes after each
> hour; and from WWVH, Kekaha, HI at 43 to 44 minutes after each hour.
>    C. Computer Bulletin Boards: parameters - 8 bits, no parity, 1 stop:
> 300-14400 baud (703) 886-3890-9600 with optional MNP capability (703)
> 866-3894
>    D. General information and printed informational materials.  Please call
> gpsic.  Phone# (703) 866-3806
>    E. Additional information concerning GPS may be obtained by calling or
> writing US Coast Guard Commandant (G-NRN-2), Washington, D.C. at (202)
> 267-0298"

I called and got the 'NAVSTAR GPS users manual' (or some such), this describes
GPS in great detail (the signal coding, frequencies, modulation, etc...). It
also has a section on applications (there are a bunch I had never though of).
They also sent me a couple of papers on DGPS and why they are doing it. Looks
pretty impressive (<8M accuracy within ~200 NM of DGPS station).

-Eric
Newsgroups: rec.aviation.ifr
From: krol@ux1.cso.uiuc.edu (Ed Krol)
Subject: Re: Interesting Navaid: ANDREW NDB
Organization: University of Illinois at Urbana
Date: Wed, 6 Jan 1993 11:09:21 GMT

rkaplan@netcom.com (Richard Kaplan) writes:

>under the old Biscayne VOR frequency.  Even
>more interesting is that there is an FDC Notam disallowing
>use of ANDREW NDB at present, yet FSS allows one
>to file direct to/from ANDREW with anticipated radar
>vectors.  I filed this way (I was VFR on top for this part

I would assume that the move happened very recently and that
the approach wasn't certified yet.  But since the navaid was
operating and it's location known it was no problem using it
as an enroute facility.

I think a approach cant be published until it is flown by one
of the magic FAA instrument certification aircraft.
From: dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin) 
Newsgroups: rec.aviation.ifr
Subject: GPS vs DGPS info needed
Date: 9 Jan 93 18:28:00 GMT
Distribution: world
Organization: Advanced Computer Concepts BBS, New Rochelle, NY 914-654-1981
Reply-To: dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin) 

KH> .Could someone give me some info on DGPS, and contract it to plain GPS.  Is
  > .that much better than GPS? Does it require additional ground equipment? I 
  > .just started my ground scholl for my IFR ticket and the subject of GPS cam
  > .When I mentioned DGPS in class, no one had a clue what I was talking about
  > .Unfortunately, neither did I.

GPS receivers compute their position by figuring their distance from
several satellites, based on information continually broadcast by those
satellites.  The military, which "owns and operates" the system, puts
some bogus information in the transmission, to intentionally reduce the
accuracy of the system and make it less usable by the "bad guys."
(Called SA, for Selective Availability)

DGPS is a system which corrects for those errors.  It requires a "ground
station" which is a GPS receiver in a precisely known position.  That
receiver compares its known position with the position it derives from
the satellite information, and produces a correction signal, which is
broadcast "locally."  An appropriately equipped GPS receiver
detects and interprets that signal, and produces a higher-accuracy
position calculation, unaffected by the SA degraded satellite signals.

That's the $0.25 explanation.  The details of how GPS works are quite
interesting.  Trimble has a booklet which goes into some more detail,
without getting submerged in math.  Worthwhile reading.

        D/
---
 . QMPro 1.0 41-3345 . Bring back A-N airways!!    Dick.Zeitlin%acc1bbs@ssr.com
From: lahurst@unix1.tcd.ie (Leon Hurst)
Subject: Help needed on IT in aviation project!
Organization: Trinity College, Dublin
Date: Tue, 12 Jan 1993 13:31:06 GMT


Hi!
I am a computer science student who has to do a project/talk 
on the impact of computers on the aviation industry and their
"social implications". I am researching two topics.

	1] How computers are used in training pilots
	(ie. simulators).

	2] How computers are used in air traffic control.

If anyone wants to help me could they email any details/reports
that they have in any of these areas. And Also if there is a
commercial pilot out there I would like to ask him some quetions 
on his own experiences.

I would be grateful for any feedback at all.
Leon Hurst.

Newsgroups: rec.aviation.simulators