HDTenEightyP/NetNews huggingface dataset:
From: lhe@sics.se (Lars-Henrik Eriksson)
Newsgroups: rec.aviation.ifr
Subject: Re: GPS and IFR Approaches
Date: 1 Jan 93 11:25:26 GMT
	<barnett.725640608@convex.convex.com>
	<1992Dec29.174022.6514@linus.mitre.org>
	<barnett.725654653@convex.convex.com>
	<1992Dec30.124200.4248@linus.mitre.org>
	<1992Dec31.011252.1593@oakhil
Organization: Swedish Institute of Computer Science, Kista

In article <1992Dec31.011252.1593@oakhill.sps.mot.com> mpaton@oakhill.sps.mot.com (Michael J Paton) writes:
   ... Is it not however true that
   if one assumes that the glideslope were perfectly accurate, and one 
   could track it perfectly, then the main problem in avoiding the ground
   is the use of a Decision Height determined in the Cat 1 ILS by a 
   barometric altimeter which may be off by + or - 75 feet. If one assesses
   the accuracy of the ground installation combined with the airborne
   equipment, does the DGPS and full constellation not then come out ahead?

No. As you say, on an ILS you could track the glideslope perfectly.
Your decision point might move closer to the runway if the altimeter
reads to high, but you would still be on the glideslope. With (D)GPS,
the glideslope itself is computed, so a position error of +-75 feet
might cause the glideslope itself to move 75 feet closer to the
ground. A very different situation!
--
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
Newsgroups: rec.aviation.ifr
From: markjo@pogo.wv.tek.com (Mark Josephsen)
Newsgroups: rec.aviation.ifr
Subject: Re: more ice!
Date: 21 Dec 92 21:36:03 GMT
Organization: Tektronix, Inc., Wilsonville,  OR.

In article <1992Dec19.012832.20359@pony.Ingres.COM> kerry@Ingres.COM (Kerry Kurasaki) writes:
>In article <1gtmuvINNjuj@hp-col.col.hp.com> davea@col.hp.com (Dave Allen) writes:
>>Regarding taxiing or taking off through slush,

>where the captain announced that he would be cycling the gear after
>takeoff to prevent such an occurrence.

Air Force procedures for their Learjets sugest leaving the gear down to let the
slush/water blow off first.  Then before landing, cycle the brakes to knock
anything off that might be on them.

Mark M. Josephsen    Phone (503) 685-3057        __!__
Tektronix, Inc.                              _____(_)_____
Graphics Printing and Imaging Division          !  !  !
Newsgroups: rec.aviation.ifr
From: barnett@convex.com (Paul Barnett)
Subject: Re: GPS and IFR Approache
Date: Tue, 29 Dec 1992 14:50:08 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 <1992Dec29.123409.28048@linus.mitre.org> Bob Noel writes:

>GPS is line-of-sight.  To provide coverage down to the DH it (the
>DGPS ground station) will be sited in manner similiar to MLS.  Thus,
>you can't have wide-area DGPS.

What if the DGPS ground station (or at least, the transmitting
antenna) was located at 1000 foot AGL on a commercial radio or TV
tower?  That would provide a significant footprint of coverage here in
the "flatlands".

Of course, reliability and availability could be adversely affected.
The antenna might get blown over or something....  Where's a mountain
when you need it?
--
Paul Barnett
MPP OS Development     (214)-497-4846
Convex Computer Corp.  Richardson, TX
Newsgroups: rec.aviation.ifr,rec.aviation.student,eunet.aviation
From: aboyd@quantum.on.ca (Andrew Boyd)
Subject: Re: nice Christmas gift
Date: Wed, 23 Dec 92 15:04:42 GMT
Organization: Quantum Software Systems

In article <WD.92Dec22110209@sam.cs.tu-berlin.de> wd@cs.tu-berlin.de 
(Wolfgang Diestelkamp) writes:

>Last Sunday I got the nicest Christmas gift I could ever think of:
>*I passed the IFR checkride*.

Congratulations!

>the requirements for the training cover the rest: 200 hours groundschool

I fervently hope that's a typo ... we don't have any ground school
requirement.  Just show up and write the test.  Jeez, I hope no one
from our (can) DOT is reading this, it'll give them really awful ideas ...

>The examiner (as it later turns out only pretends to be) exploding;

Perhaps it's just a language thing, but I don't quite understand
the point of your examiner's behaviour.  I am sure that he knows that
"hurrying up" your preparations on the ground is a good way to kill
yourself and your passengers.

Maybe it's just his style to lean on the applicants during the ride
to see what cracks develop, but I it sure sounds like unnecessary
sadism to me.

----
#include <std.disclaimer>
From: lhe@sics.se (Lars-Henrik Eriksson)
Newsgroups: rec.aviation.ifr
Subject: Re: GPS and IFR Approache
Date: 1 Jan 93 11:18:13 GMT
	<barnett.725640608@convex.convex.com>
	<1992Dec29.174022.6514@linus.mitre.org>
Organization: Swedish Institute of Computer Science, Kista

In article <1992Dec29.174022.6514@linus.mitre.org> Bob Noel writes:
   In article <barnett.725640608@convex.convex.com> barnett@convex.com (Paul
   Barnett) writes:
   >In <1992Dec29.123409.28048@linus.mitre.org> Bob Noel writes:
   >
   >>GPS is line-of-sight.  To provide coverage down to the DH it (the
   >>DGPS ground station) will be sited in manner similiar to MLS.  Thus,
   >>you can't have wide-area DGPS.
   >
   >What if the DGPS ground station (or at least, the transmitting
   >antenna) was located at 1000 foot AGL on a commercial radio or TV
   >tower?  That would provide a significant footprint of coverage here in
   >the "flatlands".
   >

   good point.  

   However, such a tower would be an obstruction that mustn't be
   allowed to penetrate protected airspace.  A tower sufficiently
   far away as to not be a navigational hazard would also be low
   on the horizon.  In that case, you still need to worry about 
   line-of-sight down to the DH (and below - for margin).  My gut
   reaction is that such a tower would be too low on the horizon
   for visibility for almost any runway.

A DGPS radio tower doesn't have to be nearly close enough to an
airport to be a problematic obstacle. In round figures, a 1000 feet
tower would give about 39 miles of theoretical coverage.
--
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
Xref: sparky rec.aviation.ifr:541 rec.aviation.simulators:813
From: falk@peregrine.Sun.COM (Ed Falk)
Newsgroups: rec.aviation.ifr,rec.aviation.simulators
Subject: Re: IFR simulator for Sun workstation
Date: 28 Dec 1992 19:39:18 GMT
Organization: Sun
Distribution: na
NNTP-Posting-Host: peregrine

In article <1992Dec11.182058.23861@Princeton.EDU> jeremy@deneb.Princeton.EDU (Jeremy Goodman) writes:
>(You may have seen this before---I tried to post this last Wednesday and
>received confirmation but the posting didn't show up at my site.)
>
>Does anyone know of an IFR simulator program that will run on a Sun 
>workstation (which is what I've got at home)?  I am an IFR student and
>would like to practice approaches inexpensively even if I can't log the time.
>

I wrote one that ran under the GP2 graphics board, and made the
source code available.  GP2's are pretty rare and I don't even know
if you can still get them.  If anybody feels like porting the code
to XGL, I can make the source code available.  I *can't* make XGL
available though, so don't even ask.

		-ed falk, sun microsystems
		 sun!falk, falk@sun.com
	"Towards the end, the smell of their air began to change"
Newsgroups: rec.aviation.ifr
From: Bob Noel
Subject: Re: Getting into a TCA without the magic words
Organization: The MITRE Corporation
Date: Mon, 21 Dec 1992 20:58:53 GMT

>In article <1992Dec21.163616.20042@eecs.nwu.edu>, phil@pex.eecs.nwu.edu
(William LeFebvre) writes:
>
>>"Cessna 73502, climb and maintain 4000".  TCA (whose floor is 3000 to
>>3600 around here)?  We don't care 'bout no stinkin' TCA!  :-)
>>...

sometimes being IFR doesn't help.  I haven't had the problem, but my
instrument instructor almost never has had the pleasure of an 
IFR clearance that would pentrate the Boston TCA (for flights between
BED and Falmouth).  He was always amused ;-) with the
radar vectors that kept him just outside the TCA.

Bob Noel
My views are my own, not MITRE's

Newsgroups: rec.aviation.ifr
From: Bob Noel
Subject: Re: GPS and IFR Approaches
Organization: The MITRE Corporation
Date: Wed, 30 Dec 1992 20:24:47 GMT

In article <barnett.725730978@convex.convex.com> barnett@convex.com (Paul
Barnett) writes:

stuff deleted

>Maybe GPS isn't a proper "replacement" for MLS, or even a full-blown
>ILS, but I'm not advocating that.  After lobbying (unsuccessfully) for
>3 years to put an NDB on my former home base, I'm just looking for a
>better alternative.
>--

I'm guessing here, but....perhaps one of the limitations on
approaches that get approved is the FAA's ability (read that
sufficient resources) to performs flight inspections of all
of the IFR approaches.  If we want the FAA to approve more approaches
(based on whatever aid: GPS, VOR, a duck), we probably need to
provide the FAA with additional flight inspection aircraft and
trained crews to inspect these approaches.  In other words, the
FAA can't just wave a wand and create hundreds of new
approaches even if no additional ground equipment is needed (as
might be the case for non-precision GPS approaches). 

Bob Noel
my views are my own, not MITRE's
From: dls@freedom.genrad.com (Diana L. Carlson)
Newsgroups: rec.aviation.ifr
Subject: Re: Getting into a TCA without the magic words
Date: 22 Dec 1992 06:56:08 -0500
Organization: GenRad, Inc.
NNTP-Posting-Host: freedom.genrad.com

In article <1992Dec21.205853.7681@linus.mitre.org> Bob Noel writes:
>sometimes being IFR doesn't help.  I haven't had the problem, but my
>instrument instructor almost never has had the pleasure of an 
>IFR clearance that would pentrate the Boston TCA (for flights between
>BED and Falmouth).  He was always amused ;-) with the
>radar vectors that kept him just outside the TCA.

I've flown thru the Boston TCA many times, both IFR and VFR.....I'd
have to say your instructor has just been unlucky.

Diana

-- 
->Diana L. (Syriac) Carlson dls@genrad.com	Ham: KC1SP (Sweet Pea)      <-
->I'D RATHER BE FLYING!	P-ASEL, INST		CAP: CPT, Freedom 690 Mobile<-
->AD ASTRA, PER ASPERA				Airplane: C-172 N6513E	    <-
->GenRad, MS/6, 300 Baker Ave, Concord, Mass.  01742  (508)369-4400 x2459   <-
From: davea@col.hp.com (Dave Allen)
Newsgroups: rec.aviation.ifr
Subject: Re: IFR icing strategies
Date: 23 Dec 1992 18:59:56 GMT
Organization: HP Colorado Springs Division
Distribution: usa
NNTP-Posting-Host: qadata.col.hp.com

geo@netcom.com (George Pontis) writes:
> All the leading edges were evenly coated, as well as the rim of the intake
> holes in the cowling. The prop spinner had a .5" diameter disk of ice on the
> very tip. The prop didn't have any ice at all.

Useful information. Thanks. The prop probably had ice that broke off when
you changed power for landing. Changing power flexes it and can shed ice :-),
though sometimes un-evenly. :-( There might come a time when you'd need to
"de-ice" your prop without equipment.

dave allen - Fly because you love it.
Newsgroups: rec.aviation.ifr
From: BCLEWIS@LSTC2VM.stortek.com (Brian Lewis)
Subject: Re: : Intersection names
Organization: StorageTek SW Engineering
Date: Wed, 23 Dec 1992 03:45:37 GMT

I found another one, one which goes in the "humorous" category (rather
than the "ill-thought-out" category):
 
Medford, Oregon has a JACKSON FIVE departure procedure.
 
Brian
Newsgroups: rec.aviation.ifr
From: Bob Noel
Subject: Re: GPS and IFR Approache
Organization: The MITRE Corporation
Date: Tue, 29 Dec 1992 17:40:22 GMT

In article <barnett.725640608@convex.convex.com> barnett@convex.com (Paul
Barnett) writes:
>In <1992Dec29.123409.28048@linus.mitre.org> Bob Noel writes:
>
>>GPS is line-of-sight.  To provide coverage down to the DH it (the
>>DGPS ground station) will be sited in manner similiar to MLS.  Thus,
>>you can't have wide-area DGPS.
>
>What if the DGPS ground station (or at least, the transmitting
>antenna) was located at 1000 foot AGL on a commercial radio or TV
>tower?  That would provide a significant footprint of coverage here in
>the "flatlands".
>

good point.  

However, such a tower would be an obstruction that mustn't be
allowed to penetrate protected airspace.  A tower sufficiently
far away as to not be a navigational hazard would also be low
on the horizon.  In that case, you still need to worry about 
line-of-sight down to the DH (and below - for margin).  My gut
reaction is that such a tower would be too low on the horizon
for visibility for almost any runway.

For non-precision approaches, the accuracy of GPS is sufficient
(DGPS would be overkill _for the accuracy_). 

Bob Noel
My views are my own, not MITRE's.

Newsgroups: rec.aviation.ifr
From: Bob Noel
Subject: Re: GPS and IFR Approache
Organization: The MITRE Corporation
Date: Tue, 29 Dec 1992 12:40:00 GMT

In article <1hnd10INN32p@mirror.digex.com> stephens@access.digex.com (John
Stephens) writes:
>Many people have contributed to this thread, and the arguments
>seem quite polarized. ( :-) )
>
stuff deleted.
>
>Despite the above, I believe in GPS. I would support GPS
>non-precision approached today, and precision approaches in the
>near future (preferably DGPS), but would still want ILS's and the
>VOR system to remain as a backup for a long, long time.  And maybe
>a goodly number of NDBs as well.
>
>
problem:  ILS will have a problem, starting in 1997 (or 1998)
FM frequency protection dissappears.  This means that existing
ILS approaches will be suspectible to FM interference (something
that's already happenning in Europe).  ILS is not a viable
approach system for the future.  GA should not count on ILS
being available.

Bob Noel
my views are my own, not MITRE's



Newsgroups: rec.aviation.ifr
From: Bob Noel
Subject: Re: Getting into a TCA without the magic words
Organization: The MITRE Corporation
Date: Tue, 22 Dec 1992 19:16:22 GMT

In article <1h6vooINN620@freedom.genrad.com> dls@freedom.genrad.com (Diana L.
Carlson) writes:
>In article <1992Dec21.205853.7681@linus.mitre.org> Bob Noel writes:
>>sometimes being IFR doesn't help.  I haven't had the problem, but my
>>instrument instructor almost never has had the pleasure of an 
>>IFR clearance that would pentrate the Boston TCA (for flights between
>>BED and Falmouth).  He was always amused ;-) with the
>>radar vectors that kept him just outside the TCA.
>
>I've flown thru the Boston TCA many times, both IFR and VFR.....I'd
>have to say your instructor has just been unlucky.
>

I too have been allowed into the TCA (mostly when IFR).  Thus, 
I take pleasure in giving him (my instructor) grief and rubbing
it in :-)



Newsgroups: rec.aviation.ifr
From: mpaton@oakhill.sps.mot.com (Michael J Paton)
Subject: Re: GPS and IFR Approaches
Date: Thu, 31 Dec 1992 01:12:52 GMT
Reply-To: mpaton@tempest.UUCP (Michael J Paton)
Organization: Motorola Inc., Austin, Texas

In article <1992Dec30.124200.4248@linus.mitre.org> Bob Noel writes:
>
>it turns out that the really important DOP is the VDOP (the _Vertical_
>DOP).  A VDOP supporting vertical accuracy almost as good as ILS Cat I
>is available only 99%. (that number is for a full constellation and DGPS)
>
Could you clarify this a bit please. I believe that I understand that 
you are saying that the best GPS VDOP results in vertical accuracy
almost as good as the Cat 1 glideslope. Is it not however true that
if one assumes that the glideslope were perfectly accurate, and one 
could track it perfectly, then the main problem in avoiding the ground
is the use of a Decision Height determined in the Cat 1 ILS by a 
barometric altimeter which may be off by + or - 75 feet. If one assesses
the accuracy of the ground installation combined with the airborne
equipment, does the DGPS and full constellation not then come out ahead?


Michael Paton
mpaton@oakhill.sps.mot.com

Newsgroups: rec.aviation.ifr
From: Bob Noel
Subject: Re: GPS and IFR Approache
Organization: The MITRE Corporation
Date: Wed, 23 Dec 1992 18:36:00 GMT

In article <1992Dec23.014001.4489@craycos.com> ewv@craycos.com (Eric Varsanyi)
writes:
>>Will the availability of the veritical accuracy of GPS (I believe the term
>>is VDOP) be sufficient for Cat II or III requirements?  btw, an 
>>availability of "most of the time" isn't good enough.
>
>Well, I would argue that 'most' of the time for GPS is much better than
>'most' of the time for any ground based system like ILS or MLS.  

from the numbers I've seen, I can't agree.

>When
>the 24 Sats are up (mid 93) there are 4 small locations (about 1 degree
>square it appears) on earth that will have a regular outage (defined as less
>that 4 sats in view). The outage will last less than 30 seconds at each
>location. 2 of the locations are in the Antarctic, over water (or ice I
>suppose) and the other 2 are in a corresponding location in the Northern
>hemisphere (there is one East of Alaska, way up north and one in
>Greenland).
>

4 birds in view is *not*, repeat *not*, a sufficient condition for a
GPS geometry with a low enough VDOP to support Cat I (or better) approaches.
The number of satellites is not really the issue, the important thing
is the precision offered by the satellite geometry (which, of course, is
strongly influenced by the number birds in view).  You can have situations
where 5 birds in view is inferior to other times with only 4 birds in view.


>I think all the other factors you could list that would affect availability
>(weather/icing, jamming, electrical failure, equipment breakage) would
>equally affect GPS and MLS, perhaps it would even be worse for MLS since
>they are on the ground and vulnerable to bad drivers.

For GPS to provide precision approaches, it appears that there must be
a ground station.  Thus, both systems will be vulnerable to unintentional
threats.

>
>>If, repeat IF, GPS can provide the integrity required for Cat I,II or III
>>approaches (and veritical accuracy), it won't be much of a contest.  
>
>Yes, I can easily see how you can compare an NDB or VOR approach with a 
>Cat III ILS approach. Not.

I'm not comparing NDB or VORs with GPS and MLS.  In this thread I've been
consistently dealing with precision approaches.

and as usual, nobody seems to worry about the integrity of GPS or DGPS.
>

Bob Noel
my views are my own, not MITRE's
From: philf@xymox.palo-alto.ca.us (Phil Fernandez)
Subject: New VOR approach to Moffett Field
Organization: Jade and Jett Incorporated
Distribution: usa
Date: Fri, 1 Jan 1993 02:03:02 GMT

As I was departing PAO this morning, talking to Bay Approach, there
was also on the frequency an FAA Flight Check aircraft working on a
new approach to NAS Moffett Field in Mountain View (NAS Moffett is on
the SF peninsula, in-between PAO and San Jose International.  The Navy
will vacate Moffett next year, but NASA Ames Research Center, also at
the field, will continue to use the airport along with Lockheed and
some other defence contractors near the field).

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.

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...

pmf
Newsgroups: rec.aviation.ifr,rec.aviation.piloting
From: kerry@Ingres.COM (Kerry Kurasaki)
Subject: Re: Frost accumulation
Reply-To: kerry@Ingres.COM (Kerry Kurasaki)
Organization: Ask Computer Systems Inc., Ingres Division, Alameda CA 94501
Date: 31 Dec 92 18:42:01 GMT

In article <1992Dec31.161612.28414@eagle.lerc.nasa.gov> tostan@dumbo.lerc.nasa.gov (Stan Mohler) writes:
>
>A recent paper by Frank T. Lynch at Douglas Aircraft, titled "The Adverse
>Aerodynamic Impact of Very Small Leading-edge Ice (Roughness) Buildups on Wings
>and Tails" will put some quantitative information into this picture.  Experi-
>ments were carried out at Langley Research Center to see how badly wing 
>performance suffered when sand-paper-type roughness was applied to the leading 
>edges of wings.  It turned out that having roughness confined approximately to
>the first 7 percent chord was about as bad as having it extend to the trailing
>edge!  

This adds some fuel to the fire of boots vs weeping wing deice systems.
One plus for the weeping wing system is that it can keep the entire
wing clear of ice.

It looks like the boots still satisfy the 90% part of the problem, e.g.
ice on the leading edge of the control surfaces.  Maybe boots aren't that
bad (vice weeping wings) after all.

Of course, you don't want to fly in ice even with the systems.  The
systems are there to buy some time to go elsewhere (out of the ice).

Kerry