henry@utzoo.uucp (Henry Spencer) (10/11/88)
In article <6400010@cpe> tif@cpe.UUCP writes: >I thought they didn't have to land in california anymore. Was this >for extra safety on this second "first" flight? Were there weather >problems forcing the landing in california? Did I miss an announced >explanation? Am I completely mistaken? Edwards is officially the primary landing site for the shuttle now. KSC is third or fourth on the list. The trouble is that the east coast of Florida is, in some ways, a lousy place for a spaceport. The weather there is too volatile. It can change significantly between shuttle retrofire and landing time. Sudden thunderstorms, in particular, are common. (This is why KSC is a favored site for lightning research.) Edwards, on the other hand, has excellent and highly-predictable weather, which is one reason why it was chosen for a flight-test base in the first place. This is one of the issues that came up in the post-Challenger reassessment of safety questions. -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
phil@titan.rice.edu (William LeFebvre) (10/12/88)
In article <1988Oct10.224026.12802@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >...The trouble is that the east coast >of Florida is, in some ways, a lousy place for a spaceport. The weather >there is too volatile. It can change significantly between shuttle >retrofire and landing time. Sudden thunderstorms, in particular, are >common.... Other differences that matter: KSC is a paved strip, Edwards is a (softer) dry lake bed. KSC is much much shorter than Edwards. KSC has nothing but swamp to either side of the strip, Edwards has more lake bed (important if you miss). Basically, there is much more room for error when you land at Edwards. Also, the KSC strip is parallel to the Atlantic coast, so whether it's a land breeze or a sea breeze you almost always have cross winds. And they just don't like the idea of landing in a cross wind (it's tough enough with a powered plane). William LeFebvre Department of Computer Science Rice University <phil@Rice.edu>
mike@ames.arc.nasa.gov (Mike Smithwick) (10/13/88)
In article <1988Oct10.224026.12802@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <6400010@cpe> tif@cpe.UUCP writes: >>I thought they didn't have to land in california anymore. Was this >>for extra safety on this second "first" flight? Were there weather >>problems forcing the landing in california? Did I miss an announced >>explanation? Am I completely mistaken? > >Edwards is officially the primary landing site for the shuttle now. >KSC is third or fourth on the list. [deleted stuff about lousy KSC weather] >The meek can have the Earth; | Henry Spencer at U of Toronto Zoology >the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu Perhaps the most important reason however is that the KSC runway is too short and too narrow to ensure safe landings. Landings must be deadly accurate, otherwise they'll run off the end of the runway. This is especially important in the case of an emergency RTLS ("return to launch site") landing when the astros are dealing with a loaded shuttle (full payload bay). In fact, the recent tightened safty requirements lowered payload capacity in the case of an aborted landing. A couple of years ago, John Young said flat out, if he had his way, no shuttle would ever land at KSC, it's just too dangerous. So the Cape will just have to serve as a backup landing site and nothing else. A couple of years ago, I got to sit in the pilots seat of our shuttle simulator while astronaut Tom Hendricks shot some landings in the commanders seat. "We" landed at the Dakar transatlantic Abort site, with a full bird. And out of two hours worth of landings, we ran off the end of the runway and into the drink nearly every time. This is why NASA is considering putting nets at the end of these sites to catch the thing if it goes too far. -- *** mike (starship janitor) smithwick *** "he's braindead Jim. . ." [disclaimer : nope, I don't work for NASA, I take full blame for my ideas]
henry@utzoo.uucp (Henry Spencer) (10/13/88)
In article <1990@kalliope.rice.edu> phil@Rice.edu (William LeFebvre) writes: >Other differences that matter: KSC is a paved strip, Edwards is a >(softer) dry lake bed... Well, there are normal paved runways at Edwards too, and I think they've been used at times, but yes, having that nice long lakebed available is comforting. You forgot one minor difference: at Edwards, they don't have to send a guy out in a jeep when you're near final approach to check that the runway is clear of alligators! -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
tif@cpe.UUCP (10/14/88)
Written 10:08 am Oct 12, 1988 by titan.UUCP!phil in cpe:sci.space.shuttle >In article <1988Oct10.224026.12802@utzoo.uucp> henry@utzoo.uucp writes: >>of Florida is, in some ways, a lousy place for a spaceport. The weather >Other differences that matter: KSC is a paved strip, Edwards is a >(softer) dry lake bed. KSC is much much shorter than Edwards. KSC has >nothing but swamp to either side of the strip, Edwards has more lake bed >(important if you miss). Basically, there is much more room for error >when you land at Edwards. ... You have good (and I'm sure valid) points but I just gotta say something about this... You talk about Edwards having lots of lake bed to hit, haven't we been within inches of the intended landing spot every time? Paul Chamberlain Computer Product Engineering, Tandy Corp. {convex,killer}!ninja!cpe!tif
jwm@stdc.jhuapl.edu (Jim Meritt) (10/14/88)
Come on, this thing is suppose to be versatile:
Use National Airport in Washington DC!
Think on THAT one, congress!!!!
Disclaimer: Individuals have opinions, organizations have policy.
Therefore, these opinions are mine and not any organizations!
Q.E.D.
jwm@aplvax.jhuapl.edu 128.244.65.5 (James W. Meritt)cjl@ecsvax.uncecs.edu (Charles Lord) (10/14/88)
In article <2137@aplcomm.jhuapl.edu>, jwm@stdc.jhuapl.edu (Jim Meritt) writes: > > Come on, this thing is suppose to be versatile: > > Use National Airport in Washington DC! No, no! Use DULLES. There *has* to be a real use for that ghost town. -- * Charles Lord ..!decvax!mcnc!ecsvax!cjl Usenet (old) * * Cary, NC cjl@ecsvax.UUCP Usenet (new) * * #include <std.disclamers> cjl@ecsvax.BITNET Bitnet * * #include <cutsey.quote> cjl@ecsvax.uncecs.edu Internet *
ewiles@netxcom.UUCP (Edwin Wiles) (10/15/88)
In article <6400012@cpe> tif@cpe.UUCP writes: > >You talk about Edwards having lots of lake bed to hit, haven't we been >within inches of the intended landing spot every time? > > Paul Chamberlain Yep, we sure have hit it each time, and we will continue to do so until the first time we don't. Something you have yet to learn, is that when you are dealing with a high risk situation you can never have too much of a saftey margin. Especially when it doesn't cost you anything. Take Care! -- ...!hadron\ "Who?... Me?... WHAT opinions?!?" | Edwin Wiles ...!sundc\ Schedule: (n.) An ever changing | NetExpress Comm., Inc. ...!pyrdc\ nightmare. | 1953 Gallows Rd. Suite 300 ...!uunet!netxcom!ewiles | Vienna, VA 22180
henry@utzoo.uucp (Henry Spencer) (10/16/88)
In article <16439@ames.arc.nasa.gov> mike@ames.arc.nasa.gov.UUCP (Mike Smithwick) writes: >...This is why NASA is >considering putting nets at the end of these sites to catch the thing if it >goes too far. Not "considering", they've done it. KSC has one, and two out of three of the other emergency landing sites for STS-26 had them. -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
rogers@src.honeywell.COM (Brynn Rogers) (10/17/88)
I was under the impression that the space shuttle HAS landed at KSC (cape canaveral :-) ) once or twice already. Don't get me wrong, I know crosswind landings can be dangerous and I would rather be safe than sorry and land at edwards.
slr@skep2.ATT.COM (Shelley.L.Rosenbaum.[ho95c]) (10/18/88)
In article <1990@kalliope.rice.edu> phil@Rice.edu (William LeFebvre) writes: >Other differences that matter: KSC is a paved strip, Edwards is a >(softer) dry lake bed. [other differences deleted] Most of the differences William listed I agree with. However, landing on a soft field is not necessarily better--landing gear could collapse, lessening of directional steering, etc. However, it is probably a moot point, since from what I understand, the dry lake bed isn't all that soft--it's about as hard as a paved surface! -- Shelley L. Rosenbaum, Air Traffic Control Systems, AT&T Bell Laboratories {allegra, att, arpa}!ho95c!slr slr@ho95c.att.arpa (201) 949-3615 "I've got my two-tones through the floorboards already!"
jwm@stdc.jhuapl.edu (Jim Meritt) (10/19/88)
In article <5590@ecsvax.uncecs.edu> cjl@ecsvax.uncecs.edu (Charles Lord) writes: }In article <2137@aplcomm.jhuapl.edu>, jwm@stdc.jhuapl.edu (Jim Meritt) writes: }> }> Come on, this thing is suppose to be versatile: }> }> Use National Airport in Washington DC! } }No, no! Use DULLES. There *has* to be a real use for that ghost town. Nah. The traffic going out there is terrible, not to mention the only toll road around. Besides, if you run into trouble landing, there is always the 14th stret bridge.... )-: (personally, I'd be more likely to see it at BWI......) Disclaimer: Individuals have opinions, organizations have policy. Therefore, these opinions are mine and not any organizations! Q.E.D. jwm@aplvax.jhuapl.edu 128.244.65.5 (James W. Meritt)
henry@utzoo.uucp (Henry Spencer) (10/21/88)
In article <10325@srcsip.UUCP> rogers@orion.UUCP (Brynn Rogers) writes: >I was under the impression that the space shuttle HAS landed >at KSC (cape canaveral :-) ) once or twice already. Yes, it's been done. Before Challenger there was an avowed plan to make as many landings at KSC as possible, since it simplified matters in a number of ways. -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
leem@jplpro.JPL.NASA.GOV (Lee Mellinger) (10/25/88)
In article <1730@eos.UUCP> eugene@eos.UUCP (Eugene Miya) writes: |In article <6400012@cpe> tif@cpe.UUCP writes: | |But--- the principal advantage to Murdoc Lake is the relatively good weather ^^^^^^ |and fairly consistent winds from the West. This is due to the Mtns |formed by the San Andreas and Garlock faults. A wedge shaped |angle which nearly points into the prevailing winds. This consistency helps |get most of those inches. It's hard to tell velocity of something you |can't see moving air) [with any range, before anyone mentions radar]. | |--eugene miya, NASA Ames Research Center, eugene@aurora.arc.nasa.gov That's Muroc, Gene, close but no cigar. Lee -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- |Lee F. Mellinger Jet Propulsion Laboratory - NASA| |4800 Oak Grove Drive, Pasadena, CA 91109 818/393-0516 FTS 977-0516 | |-------------------------------------------------------------------------| |UUCP: {ames!cit-vax,psivax}!elroy!jpl-devvax!jplpro!leem | |ARPA: jplpro!leem!@cit-vax.ARPA -or- leem@jplpro.JPL.NASA.GOV | -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
klr@hadron.UUCP (Kurt L. Reisler) (10/26/88)
In article <5590@ecsvax.uncecs.edu> cjl@ecsvax.uncecs.edu (Charles Lord) writes: >In article <2137@aplcomm.jhuapl.edu>, jwm@stdc.jhuapl.edu (Jim Meritt) writes: >> >> Come on, this thing is suppose to be versatile: >> >> Use National Airport in Washington DC! > >No, no! Use DULLES. There *has* to be a real use for that ghost town. You have not been to Dullas lately have you? It is getting difficult to even get a parking space out there! However, I have heard tales that Dullas is large enough (long enough in the runway department) to serve as an emergency landing site. However, the location is wrong.
axelson@dasys1.UUCP (Kevin Axelson) (10/27/88)
In article <794@hadron.UUCP>, klr@hadron.UUCP (Kurt L. Reisler) writes: > > ... I have heard tales that Dullas is large enough (long enough in > the runway department) to serve as an emergency landing site. However, > the location is wrong. And a commercial jetliner crashed in the hills just to the west of the airport a few years back. Geography is a problem. Actually, stretches of the adjoining interstate are so straight that they might do the trick. A lot of the drivers seem to be doing Mach 1, too. Seriously, I'd have thought that a lot of military airstrips would be better candidates than commercial airports. Is this a misconception? Kevin Axelson axelson@dasys1.uucp
craig@think.COM (Craig Stanfill) (10/27/88)
In article <7225@dasys1.UUCP> axelson@dasys1.UUCP (Kevin Axelson) writes: >In article <794@hadron.UUCP>, klr@hadron.UUCP (Kurt L. Reisler) writes: >> >> ... I have heard tales that Dullas is large enough (long enough in >> the runway department) to serve as an emergency landing site. However, >> the location is wrong. > >And a commercial jetliner crashed in the hills just to the west of >the airport a few years back. Geography is a problem. The hills would not be a problem. They are only 1500 ft tall or so, and are 60 miles from the runway. This is a problem if you are gliding in at a 200:1 slope, but not much of an obstacle for our beloved brick. Also, assuming that Dullas was to be used as an emergency landing site during high-inclination launches (I missed part of this discussion), the hills (to the _west_ of the airport) are not even on the likely flight path. - Craig
johnl@gronk.UUCP (John Limpert) (10/27/88)
In article <7225@dasys1.UUCP> axelson@dasys1.UUCP (Kevin Axelson) writes: >In article <794@hadron.UUCP>, klr@hadron.UUCP (Kurt L. Reisler) writes: >> ... I have heard tales that Dullas is large enough (long enough in >> the runway department) to serve as an emergency landing site. However, >> the location is wrong. The runways at Dulles are long, 10,000 feet if I remember correctly. >And a commercial jetliner crashed in the hills just to the west of >the airport a few years back. Geography is a problem. I believe the plane flew right into a hill adjacent to the "secret" Mt. Weather installation during a landing approach with bad visibility. This was a considerable distance from Dulles Airport. >Seriously, I'd have thought that a lot of military airstrips would be >better candidates than commercial airports. Is this a misconception? While many commercial airports have relatively short runways, Dulles should compare favorably to the typical military airbase. -- John Limpert johnl@gronk.UUCP uunet!n3dmc!gronk!johnl
dsmith@hplabsb.HP.COM (David Smith) (10/28/88)
>> ... I have heard tales that Dullas is large enough (long enough in >> the runway department) to serve as an emergency landing site. However, >> the location is wrong. > >And a commercial jetliner crashed in the hills just to the west of >the airport a few years back. Geography is a problem. If an object coming into Dulles on a Shuttle-like glidepath is in danger of hitting the hills, then I don't want to fly there. :-) /2 -- David Smith HP Labs dsmith@hplabs.hp.com
steve@polyslo.CalPoly.EDU (Steve DeJarnett) (10/29/88)
In article <370@gronk.UUCP> johnl@gronk.UUCP (John Limpert) writes: >In article <7225@dasys1.UUCP> axelson@dasys1.UUCP (Kevin Axelson) writes: >>In article <794@hadron.UUCP>, klr@hadron.UUCP (Kurt L. Reisler) writes: >>> ... I have heard tales that Dullas is large enough (long enough in >>> the runway department) to serve as an emergency landing site. However, >>> the location is wrong. > >The runways at Dulles are long, 10,000 feet if I remember correctly. And the runways at LAX are (well, at least one of them is) 11,000+ feet long. That alone doesn't qualify it to be a shuttle landing site. As I recall (this is a LONG time back, so I could be wrong), the runway at KSC is reenforced a LOT to support the shuttle weight. Although I would guess that the shuttle landing empty would be light enough for most commercial airport runways, I'm not sure what the weight of a fully laden shuttle would be, and whether these runways could support the load. There is also the question of population around an airport (as I recall, Dulles is pretty isolated (relatively), but it is still something to consider). Military bases are generally more isolated, better equipped to handle a shuttle landings (how many commercial airports have shuttle lifting equipment (of course, MOST military bases don't either)??). Length is NOT the only prerequisite for landing something (a shuttle) somewhere. ------------------------------------------------------------------------------- | Steve DeJarnett | Smart Mailers -> steve@polyslo.CalPoly.EDU | | Computer Systems Lab | Dumb Mailers -> ..!ucbvax!voder!polyslo!steve | | Cal Poly State Univ. |------------------------------------------------| | San Luis Obispo, CA 93407 | Managing faculty is like hearding cats. | -------------------------------------------------------------------------------
dkrause@orion.cf.uci.edu (Doug Krause) (10/30/88)
In article <5157@polyslo.CalPoly.EDU> steve@polyslo.UUCP (Steve DeJarnett) writes: > And the runways at LAX are (well, at least one of them is) 11,000+ >feet long. That alone doesn't qualify it to be a shuttle landing site. Two of the runways are longer than 11,000 feet. I know that one of the four was torn up this last year in order to be rebuilt. I don't know which one, so these figures might not be accurate to date. Runway Length Width ------ ------ ----- 24R 9525 150 24L 10285 150 25R 12091 150 25L 12000 200 Also remember that the shuttle only gets one shot. If it lands going west (as all regular flights do) and blows it, the shuttle is in the Pacific. If it screws up going east, it lands in The Forum. :-) Douglas Krause "East is east... let's keep it that way." -------------------------------------------------------------------- University of California, Irvine ARPANET: dkrause@orion.cf.uci.edu "Irvine? Where's Irvine?" BITNET: DJKrause@ucivmsa
klr@hadron.UUCP (Kurt L. Reisler) (10/31/88)
In article <7225@dasys1.UUCP> axelson@dasys1.UUCP (Kevin Axelson) writes: >In article <794@hadron.UUCP>, klr@hadron.UUCP (Kurt L. Reisler) writes: >> >> ... I have heard tales that Dullas is large enough (long enough in >> the runway department) to serve as an emergency landing site. However, >> the location is wrong. > >And a commercial jetliner crashed in the hills just to the west of >the airport a few years back. Geography is a problem. Actually, the crash site near Mt Weather is quite a bit west of IAD. But you are correct that the proximity of the Shenendoah Mountains would present a problem. I also think the landed gentry in the surrounding countryside might object as well :-) >Actually, stretches of the adjoining interstate are so straight that >they might do the trick. A lot of the drivers seem to be doing Mach 1, too. But, give the psychological profile of the average driver in the greater DC area, I rather doubt that the average drive would yield to an approaching space shuttle :-) >Seriously, I'd have thought that a lot of military airstrips would be >better candidates than commercial airports. Is this a misconception? Well, I would guess that on average a military airstrip is built to allow for the relatively STOL characteristics of most of their inventory. But, does can anyone compare the take-off and landing profiles of a C5A with the shuttle?
adolph@ssc-vax.UUCP (Mark C. Adolph) (11/01/88)
In article <5157@polyslo.CalPoly.EDU>, steve@polyslo.CalPoly.EDU (Steve DeJarnett) writes: > As > I recall (this is a LONG time back, so I could be wrong), the runway at > KSC is reenforced a LOT to support the shuttle weight. Although I would > guess that the shuttle landing empty would be light enough for most > commercial airport runways, I'm not sure what the weight of a fully laden > shuttle would be, and whether these runways could support the load. Does a fully laden shuttle really weigh more than a 747-400 loaded with ~550 passengers and their vacation souvenirs? -- -- Mark A. ...uw-beaver!ssc-vax!adolph
wendt@arizona.edu (Alan Lee Wendt) (11/01/88)
In article <2349@ssc-vax.UUCP>, adolph@ssc-vax.UUCP (Mark C. Adolph) writes: > > Does a fully laden shuttle really weigh more than a 747-400 loaded with > ~550 passengers and their vacation souvenirs? > Is that an African or a European shuttle? "I don't know -- arrrrrrrgh." Alan W.
dkrause@orion.cf.uci.edu (Doug Krause) (11/01/88)
In article <2349@ssc-vax.UUCP> adolph@ssc-vax.UUCP (Mark C. Adolph) writes: >In article <5157@polyslo.CalPoly.EDU>, steve@polyslo.CalPoly.EDU (Steve DeJarnett) writes: >> As >> I recall (this is a LONG time back, so I could be wrong), the runway at >> KSC is reenforced a LOT to support the shuttle weight. Although I would >> guess that the shuttle landing empty would be light enough for most >> commercial airport runways, I'm not sure what the weight of a fully laden >> shuttle would be, and whether these runways could support the load. > >Does a fully laden shuttle really weigh more than a 747-400 loaded with >~550 passengers and their vacation souvenirs? I can't quote weights of either craft, but I know that if a 747 going out of LAX has to abort the flight, it has to dump most of it's fuel into the Pacific before returning to land. Now I don't know if the weak part is the landing gear or the runway, but a loaded 747 is ob- viously VERY heavy. Douglas Krause "East is east... let's keep it that way." -------------------------------------------------------------------- University of California, Irvine ARPANET: dkrause@orion.cf.uci.edu "Irvine? Where's Irvine?" BITNET: DJKrause@ucivmsa
tif@cpe.UUCP (11/03/88)
Written 12:36 pm Oct 31, 1988 by ssc-vax.UUCP!adolph in cpe:sci.space.shuttle >Does a fully laden shuttle really weigh more than a 747-400 loaded with >~550 passengers and their vacation souvenirs? Hopefully it's obvious that the difference in their distributions could play a role as well. Paul Chamberlain Computer Product Engineering, Tandy Corp. bellcore!motown!sys1!cpe!tif
mears@hpindda.HP.COM (David B. Mears) (11/03/88)
> / hpindda:sci.space.shuttle / dkrause@orion.cf.uci.edu (Doug Krause) / 4:18 am Nov 1, 1988 / > > I can't quote weights of either craft, but I know that if a 747 going > out of LAX has to abort the flight, it has to dump most of it's fuel > into the Pacific before returning to land. Now I don't know if the > weak part is the landing gear or the runway, but a loaded 747 is ob- > viously VERY heavy. > > Douglas Krause "East is east... let's keep it that way." > -------------------------------------------------------------------- > University of California, Irvine ARPANET: dkrause@orion.cf.uci.edu > "Irvine? Where's Irvine?" BITNET: DJKrause@ucivmsa > ---------- I would hazard a guess that dumping the fuel has nothing to do with the weight of the aircraft, but is done for fire safety reasons. I think this is pretty standard in commercial aviation (though I could be mistaken). David B. Mears Hewlett-Packard Cupertino CA hplabs!hpda!mears
billa@cvedc.UUCP (Bill Anderson) (11/04/88)
In article <1144@orion.cf.uci.edu> dkrause@orion.cf.uci.edu (Doug Krause) writes: >I can't quote weights of either craft, but I know that if a 747 going >out of LAX has to abort the flight, it has to dump most of it's fuel >into the Pacific before returning to land. Now I don't know if the >weak part is the landing gear or the runway, but a loaded 747 is ob- >viously VERY heavy. I suspect the reason for dumping the fuel has much more to do with reducing the risk/severity of fire in the event of a crash than it has to do with reducing the weight of the aircraft. =============================================================== _____ __ Bill Anderson ..tektronix!reed!cvedc!wanderson | __| / / Computervision ..sun!cvbnet!cvedc!wanderson | ( / / 14952 NW Greenbrier Parkway FAX (503) 645-4734 | \_/ / Beaverton, Oregon 97006 Phone (503) 645-2410 \______/
dorn@fabscal.UUCP (Alan Dorn Hetzel Jr.) (11/04/88)
A shuttle landing full doesn't weigh as much as a 747 landing with a half load of fuel...! Reinforcement is cute, but not beyond what any good jet runway would be.
alastair@geovision.uucp (Alastair Mayer) (11/05/88)
In article <1144@orion.cf.uci.edu> dkrause@orion.cf.uci.edu (Doug Krause) writes: >In article <2349@ssc-vax.UUCP> adolph@ssc-vax.UUCP (Mark C. Adolph) writes: >>In article <5157@polyslo.CalPoly.EDU>, steve@polyslo.CalPoly.EDU (Steve DeJarnett) writes: >>> As >>> I recall (this is a LONG time back, so I could be wrong), the runway at >>> KSC is reenforced a LOT to support the shuttle weight. Although I would >>> guess that the shuttle landing empty would be light enough for most >>> commercial airport runways, I'm not sure what the weight of a fully laden >>> shuttle would be, and whether these runways could support the load. >> >>Does a fully laden shuttle really weigh more than a 747-400 loaded with >>~550 passengers and their vacation souvenirs? > >I can't quote weights of either craft, but I know that if a 747 going >out of LAX has to abort the flight, it has to dump most of it's fuel >into the Pacific before returning to land. Now I don't know if the >weak part is the landing gear or the runway, but a loaded 747 is ob- >viously VERY heavy. Don't forget, the KSC shuttle landing strip not only has to support the landing weight of the orbiter, but that of a fully-loaded 747 - specifically, the NASA 747 ferry aircraft with the shuttle orbiter strapped to it's back. I guarantee you that is considerably heavier than a "fully laden shuttle" (think of it in terms of the orbiter carrying the equivalent weight of a 747!!) As for dumping fuel for emergency landings, the problem can hardly be the weight on gear or runway -- after all, the thing has already been taxiing around with a full load before it took off! No, the fuel dumping is done for a couple of reasons - to reduce the mass that the aircraft brakes will have to slow down (sure, they *can* handle a fully loaded 747 at takeoff speed in case of aborted takeoff, but it doesn't do the brakes any good), and also to reduce the amount of fuel that could be involved in any post-crash fire, if the emergency landing ain't too smooth. The former reason is probably the stronger reason, reduce the mass to reduce the braking effort needed (which in turn reduces the chance of further damage from locked brakes, blown tires, etc). The 747+orbiter combo has landed at quite a few airports other than KSC and Edwards -- indeed I don't think it can make the ferry trip without refueling a couple of times along the way (the 747 can't take on full fuel, and has a *lot* of extra drag from the orbiter). I imagine most airports handling heavy jets could handle shuttle landings -- given the precise navigation systems required for the one shot at landing.
bgm@client2.dciem.dnd.ca (Bruce Matthews) (11/08/88)
In article <3330011@hpindda.HP.COM> mears@hpindda.HP.COM (David B. Mears) writes: >> I can't quote weights of either craft, but I know that if a 747 going >> out of LAX has to abort the flight, it has to dump most of it's fuel >> into the Pacific before returning to land. Now I don't know if the >> weak part is the landing gear or the runway, but a loaded 747 is ob- >> viously VERY heavy. >I would hazard a guess that dumping the fuel has nothing to do with the >weight of the aircraft, but is done for fire safety reasons. I think >this is pretty standard in commercial aviation (though I could be >mistaken). Not correct. The maximum landing weight of most wide body airliners is a good deal lower than the maximum take-off weight. The fuel dump is required to bring the aircraft weight down to the max landing weight. The limiting factor is the landing gear. Landing a 747 at close to max take-off weight would run a serious risk of landing gear collapse. The resulting fire would then be another problem. BGM
holroyd@dinl.uucp (kevin w. holroyd) (11/12/88)
In article <1185@client2.dciem.dnd.ca> bgm@client2.dciem.dnd.ca (Bruce Matthews) writes: >In article <3330011@hpindda.HP.COM> mears@hpindda.HP.COM (David B. Mears) writes: stuff deleted >>I would hazard a guess that dumping the fuel has nothing to do with the >>weight of the aircraft, but is done for fire safety reasons. I think >>this is pretty standard in commercial aviation (though I could be >>mistaken). > >Not correct. The maximum landing weight of most wide body airliners is a >good deal lower than the maximum take-off weight. The fuel dump is >required to bring the aircraft weight down to the max landing weight. The >limiting factor is the landing gear. Landing a 747 at close to max >take-off weight would run a serious risk of landing gear collapse. The >resulting fire would then be another problem. > >BGM They also dump the fuel if the landing gear doesn't come down. Obviously at this point overloading the landing gear no longer is a factor. It is to reduce the risk of fire, that they dump fuel. In addition, the plane must be at or below max landing weight. Kevin W. Holroyd CFI Aspen Flying Club Denver CO.
steve@eos.UUCP (Steve Philipson) (11/15/88)
We've been seeing a lot of speculation on the net recently on why jets dump fuel before an emergency return-to-airport landing when that event occurs shortly after takeoff. Almost all of the speculation was wrong. Here are excerpts from the posts: dkrause@orion.cf.uci.edu(Doug Krause) starts off with the question: >I can't quote weights of either craft, but I know that if a 747 going >out of LAX has to abort the flight, it has to dump most of it's fuel >into the Pacific before returning to land. Now I don't know if the >weak part is the landing gear or the runway, but a loaded 747 is ob- >viously VERY heavy. dtynan@sultra.UUCP (Der Tynan) writes: >It seems to me, that the reason for fuel dumping, is safety. Of course, I >don't fly 747's very often :-), so this isn't much more than idle speculation. >However, that said, I wouldn't like the idea of being on a 747 during the >most difficult phase of the flight, when the fuel tanks (which contain VERY >flammable fuel) are full, but again, this is just an opinion... mears@hpindda.HP.COM (David B. Mears) writes: >I would hazard a guess that dumping the fuel has nothing to do with the >weight of the aircraft, but is done for fire safety reasons. ... billa@cvedc.UUCP (Bill Anderson) writes: >I suspect the reason for dumping the fuel has much more to do with >reducing the risk/severity of fire in the event of a crash than it has >to do with reducing the weight of the aircraft. eriks@cadnetix.COM (Eriks Ziemelis) writes: With regards to the 747 landing/dumping fuel: Being an ex-Boeing employee, I can atest to the fact that fuel is dumped for safety reasons. ... Finally, bgm@client2.dciem.dnd.ca (Bruce Matthews) writes: >Not correct. The maximum landing weight of most wide body airliners is a >good deal lower than the maximum take-off weight. The fuel dump is >required to bring the aircraft weight down to the max landing weight. The >limiting factor is the landing gear. Landing a 747 at close to max >take-off weight would run a serious risk of landing gear collapse. The >resulting fire would then be another problem. Good job, Bruce. To support that post, I present the following data: Variant Max T/0 Wt. Max landing wt. 747-100SR 600,000 lbs 525,000 747-100B 750,000 564,000 747-136 710,000 564,000 747-200B,C 833,000 630,000 747-300 833,000 630,000 747-400 870,000 630,000 Thanks to John R. Gersh and Hon Wah Chin for looking up the numbers. John also made the following observation: The common max landing weight for the last three variants also seems to argue for a structural consideration for some component(s) (landing gear?) common to all three. Indeed, landing gear and its supporting structure are the main factor in the common max landing weights. As for fire risk, the risk is lower with full tanks than partially filled tanks. The problem in post-crash fires is not raw fuel, but rather fuel vapor. A carburetor on an engine is there to mix fuel and air in precise ratio to optimize combustion. Tanks with lots of vapor in them are thus much more likely to explode when punctured (and sparks are generated) then those that have little or no vapor. Sure, you don't add "fuel to the fire", but the objective is to not start a fire in the first place. Most returns for landing are precautionary in nature; a crash is NOT anticipated. There is another important reason to dump fuel. holroyd@dinl.uucp (kevin w. holroyd) observes that they dump fuel even when they won't be landing on the gear: >They also dump the fuel if the landing gear doesn't come down. Obviously >at this point overloading the landing gear no longer is a factor. It is >to reduce the risk of fire, that they dump fuel. In addition, the plane >must be at or below max landing weight. The observation is correct, but the reasons are not. Max landing weight is a structural consideration for the gear, so it is not pertintent for a belly landing. What IS important is that the touchdown speed be minimized, both to minimize the length of the landing roll (or slide, in te case of a gear-up landing) and to minimize impact and deceleration force. A jetliner carries a large percentage of its maximum weight in fuel. The higher its weight, the higher its stall speed and landing speed. Dumping most of its fuel would allow a jet to decrease its landing speed by about 20 to 30 knots (very approximate figure here). Reducing aircraft weight by dumping fuel has a few other important effects. Reduced weight results in an immediate increase in climb performance. This would be considered critical if there is terrain to climb over. Stall speed is reduced, so if there are configuration problems (stuck flaps, slats, etc.) a greater speed margin is available over stall speed. Lighter weights also reduce the wheel braking power required to stop the aircraft. In most cases, the operating procedures are not set up to minimize post-crash fires, but to eliminate crashes. Lower weights reduce the demands placed on the flight crew and aircraft components, making a successful emergecny landing (with no additional damage or fatalities) much more likely. -- Steve (the certified flying fanatic) steve@aurora.arc.nasa.gov
holroyd@dinl.uucp (kevin w. holroyd) (11/16/88)
In article <1914@eos.UUCP> steve@eos.UUCP (Steve Philipson) writes: <stuff deleted> >A jetliner carries a large percentage of its maximum weight in fuel. The >higher its weight, the higher its stall speed and landing speed. Dumping >most of its fuel would allow a jet to decrease its landing speed by about >20 to 30 knots (very approximate figure here). > > Reducing aircraft weight by dumping fuel has a few other important >effects. Reduced weight results in an immediate increase in climb performance. >This would be considered critical if there is terrain to climb over. Stall >speed is reduced, so if there are configuration problems (stuck flaps, slats, >etc.) a greater speed margin is available over stall speed. Lighter >weights also reduce the wheel braking power required to stop the aircraft. > > In most cases, the operating procedures are not set up to minimize >post-crash fires, but to eliminate crashes. Lower weights reduce the >demands placed on the flight crew and aircraft components, making a >successful emergecny landing (with no additional damage or fatalities) >much more likely. >-- > > Steve > (the certified flying fanatic) > steve@aurora.arc.nasa.gov Just to back up Steve, I checked with my buddies that fly the BIG IRON, and they confirmed that the reason they dump fuel is to reduce the approach speed. In light planes, part of the forced landing checklist includes shutting down fuel, electrical, and engine systems prior to touchdown. In the airliners, it turns out that they don't shut off the engines until after touchdown. At that point if the airplane is going to come apart, it is probably already happening. The major reason for fire is the fuel air explosion caused by the fuel dispersing at high velocity (due to the crash speed), being touched off by the engine ignition systems. At any rate, they dump fuel to reduce touchdown speed. Kevin W. Holroyd CFI Aspen Flying Club Denver CO.
mplubrat@athena.mit.edu (Mark P. Lubratt) (11/16/88)
I believe I read an article that stated the 747-400 recently set a new gross weight record for takeoff somewhere in Montana. The weight was on the order of 850,000 lbs. Mark P. Lubratt
wgm@mitre-bedford.ARPA (Gregory M. Woodhouse) (11/16/88)
In article <3330011@hpindda.HP.COM> mears@hpindda.HP.COM (David B. Mears) writes: > >I would hazard a guess that dumping the fuel has nothing to do with the >weight of the aircraft, but is done for fire safety reasons. I think >this is pretty standard in commercial aviation (though I could be >mistaken). > >David B. Mears Fuel Dumping is done for weight reasons. I have had to dump fuel in fighers several times, since fighters routinely take off at a gross weight greater than their maximum landing weight. Heavy aircraft (both fighters and airliners fall into this category) increase their landing speeds based on their landing gross weights. A fully loaded fighter would have to land at a speed that would exceed the limitations on the tires (200kts on an F-105G for instance) so that fuel would have to be dumped (or in the case of the F-105G, burned using "burners and boards") to reduce the landing speed below acceptable limits. Greg Woodhouse wgm@mitre-bedford.arpa
eriks@cadnetix.COM (Eriks Ziemelis) (11/17/88)
True. You do get better "handling", your gear won't collapse, fuel will
not mist over heat sources, etc. It still boils down to safety in my
book; a safer, less dangerous landing.
Eriks A. Ziemelis
Internet: eriks@cadnetix.com
UUCP: ...!{uunet,boulder}!cadnetix!eriks
U.S. Snail: Cadnetix Corp.
5775 Flatiron Pkwy
Boulder, CO 80301
Baby Bell: (303) 444-8075 X221eriks@cadnetix.COM (Eriks Ziemelis) (11/17/88)
In article <7985@bloom-beacon.MIT.EDU> mplubrat@athena.mit.edu (Mark P. Lubratt) writes: >I believe I read an article that stated the 747-400 recently set >a new gross weight record for takeoff somewhere in Montana. The weight >was on the order of 850,000 lbs. > >Mark P. Lubratt Flame at me! Go ahead! Rec.aviation is talking about tie downs vs. hangers. Not quite as interesting to me as Stealth [bomber|fighter], [Boeing|MacDoug] airplanes, and space shuttles. Got to read sci.space to get other jet fixes. Back to the follow-up. Could be the new Airforce-1. Don't remember the specifics but the AF1 had to get bigger engines than standard 747 configs. Boeing almost lost the contract because GE (I think) almost didn't get the engine into production in time. The AF1 had many weight and range requirements impossed: the bird has to haul a complete secure communications system plus backup for starters. The plane had to be reinforced to carry all the added weight (AF1 will be rated at a greater gross weight than commercial 747, I think). Touches include a complete Yamaha sound system (I know, rec.audio: you figure they would put in something a little bit nicer.) When I left, they were behind schedule. They are/were hoping to have it finished to Inauguration Day so Reagan can fly home in it. The plane was still primer green and some the electronics that had to be designed for it were behind schedule. Airframe was built in Seattle (plain Jane 747 I believe), re-inforcements and enhancements done at the military division in Wichita, KS. AF2 should be started by now too. Now that I have droned on, I think the 747 in question took off from Edwards or Boeing Field as part of FAA certification. Eriks A. Ziemelis Internet: eriks@cadnetix.com UUCP: ...!{uunet,boulder}!cadnetix!eriks U.S. Snail: Cadnetix Corp. 5775 Flatiron Pkwy Boulder, CO 80301 Baby Bell: (303) 444-8075 X221
deanp@hplsla.HP.COM (Dean Payne) (11/19/88)
>From: mplubrat@athena.mit.edu (Mark P. Lubratt) >I believe I read an article that stated the 747-400 recently set >a new gross weight record for takeoff somewhere in Montana. The weight >was on the order of 850,000 lbs. Moses Lake, Washington, 892,450 lbs, according to Aviation Leak.
jallred@bbn.com (John Allred) (11/19/88)
In article <434@geovision.UUCP> alastair@geovision.UUCP (Alastair Mayer) writes: >As for dumping fuel for emergency landings, the problem can hardly >be the weight on gear or runway -- after all, the thing has already >been taxiing around with a full load before it took off! The problem *is* weight on the gear -- the gear has to take the stress of all that weight coming down at > 3 ft/sec, which is much more strenuous that taxiing around with the same weight. Lowering the mass that the brakes have to stop is a secondary reason. The ultimate in weight reduction for landings is the F-14 Tomcat. The F-14 can take off with 6 Phoenix missiles (at one million dollars a copy.) However, it can only land with 3 (carrier landings occur at 10 ft/sec vertical speed). So, if a Tomcat takes off with 6 Phoenixs, and doesn't shoot any, 3 million dollars of the taxpayer's money goes in the ocean. Needless to say, Tomcats don't load up with 6 Phoenix missiles very often. ____ John Allred BBN Systems and Technologies Corp. (jallred@bbn.com) A truly wise man never plays leapfrog with a unicorn.
bgm@client2.dciem.dnd.ca (Bruce Matthews) (11/22/88)
In article <434@geovision.UUCP> alastair@geovision.UUCP (Alastair Mayer) writes: > >As for dumping fuel for emergency landings, the problem can hardly >be the weight on gear or runway -- after all, the thing has already >been taxiing around with a full load before it took off! No, the >fuel dumping is done for a couple of reasons - to reduce the mass >that the aircraft brakes will have to slow down (sure, they *can* >handle a fully loaded 747 at takeoff speed in case of aborted takeoff, >but it doesn't do the brakes any good), and also to reduce the >amount of fuel that could be involved in any post-crash fire, if >the emergency landing ain't too smooth. The former reason is probably >the stronger reason, reduce the mass to reduce the braking effort >needed (which in turn reduces the chance of further damage from locked >brakes, blown tires, etc). I don't want to wet on your charcoals, but as Steve and I have pointed out - it IS the weight on the gear. Saving the brakes is not a factor. For the FAA to certify an aircraft it must pass a brake test: the aircraft is put through a refused take-off (aka aborted take-off) at max take-off weight. The speed at the abort time is V1 (critical engine failure recognition speed) - any faster and you better decide to fly. After the aircraft comes to a full stop, it must sit for 5 minutes without fire breaking out in the landing gear area. When this test was done with the 747-400, the carbon brakes glowed red for a number of minutes, but no fire resulted. Sure the brakes may be next to useless afterward, but they are cheaper to replace than entire landing gear assemblies. The approach speed argument seen earlier is also a secondary factor - but if you bounce a 747 at higher than max landing weight, the next bounce will likely put the gear struts through the cabin floor and into the wings as well. (Yes I have seen a 747 bounced - severely!) BGM