Guest

Big Planes At DCA

Fri Jul 21, 2000 2:00 pm

Why doesn't the government allow bigger planes at DCA? If they let big things like 747s, or A340s land there, airlines would have more seats available and could lower fares. Also, there should be international flights from DCA. Like maybe if Quantas or a foreign carrier moved in, it would really expand the DCA service area.
 
NYC-air
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RE: Big Planes At DCA

Fri Jul 21, 2000 2:08 pm

Last time I checked DCA had really short runways. A 747 couldn't carry much if it were to safely take off on those things.

~NYC-AIR

 
Guest

RE: Big Planes At DCA

Fri Jul 21, 2000 2:23 pm

Couldn't the airlines just takeoff from the runways faster so they don't need as much space? Or they could extend the runways further into the water like they did at LGA.
 
futureatp
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RE: Big Planes At DCA

Fri Jul 21, 2000 3:20 pm

Its to my knowledge the largest aircraft allowed to fly into DCA is the 767-200 however the 757 is now the largest aircraft to serve it though. I ve heard that the taxiways at dca are really too small for the 767(so ive heard). In my opinion the runways are just to short to allow safe widebody takeoffs. What if a fully loaded widebody twin was to have an engine failure at or just below v1. I am not aware of the procudures involved but it is my guess that they would not have enough runway to stop or allow an extended takeoff run on one engine. I say that with no knowledge of the numbers used in figuring how an airliner is operated. They are different than a cessna172!

john
 
jonnyboy
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RE: Big Planes At DCA

Fri Jul 21, 2000 9:22 pm

I guarantee you won't see any widebodies at DCA unless they extend the runways.

I was there in May and on a hot day a full 757 has trouble getting off. And only one of the three runways is long enough for their takeoffs anyway.

Expansion would be too difficult into the potomac, and would make the turns after takeoff even harder. They have to avoid the White House etc. Throw in the noise objections...i'm afraid its never gonna happen.
 
AA777
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RE: Big Planes At DCA

Fri Jul 21, 2000 11:31 pm

They could expand the runway into the potomac, they must do it at the end of RWY 19, so they can taxi up the river and then the runway will end at the same place at RWY 1. SO, if the planes landed on 19 OR 1, they will have extra space to land in, and if they take off on 19 OR 1 they will have more runway length to use, and therefore larger planes could theoretically be allowed. But then there is the DCA small taxiways, that looked small even for the 757....
A 747 Could never use DCA ( this is for USA Flyer 737 ) I am afraid it wont ever happen, ever... It requires at least 8,000 or 9,000 feet of takeoff space. Not to mention that it is extremely wide, heavy, and the wingspan of the plane would probably take up 2 gates at DCA....hehehe.
-AA777
 
mlsrar
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RE: Big Planes At DCA

Fri Jul 21, 2000 11:40 pm

If I'm not mistaken, there are also route-length restricitions/max pax restrictions similar to those at Love field in Dallas (DAL). With restrictions similar to those, there would be little justifications for the capacity, range capability of most widebodies-plus, as AA777 said, rwy length is a limiting factor. On a 95 degree, humid day in DC, a fully loaded 757 has extreme trouble making the steep takeoff angle and noise-abatement turn (even for a 757!)
I mean, for the right price I’ll fight a lion. - Mike Tyson
 
akelley728
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RE: Big Planes At DCA

Fri Jul 21, 2000 11:44 pm

DCA in it's current incartation is not meant to be an International airport, period. Like everybody has said, DCA is a very difficult airport to take off or land in, because of the runways. DCA is much like LaGuardia in NYC, it's a domestic airport, period.

That's why there's Dulles!
 
D L X
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RE: Big Planes At DCA

Fri Jul 21, 2000 11:54 pm

This is pure fiction about the 757. The 757 has excellent hot and high performance, and that is the reason it is used in many places. (DEN, PHX, and SNA come to mind.) Besides that, hot days in DC are also humid. That humidity thickens the air giving wings more "grip."

The runways at DCA are adequate for even a DC10 on a short run to ORD. (Remember, the DC10 was designed to fly LGA-ORD.) The real problem with DCA is the severe lack of taxiway space for long wings, and the complete lack of ramp space for anything larger than a 757 to park at. 2 years ago when the DC10 had a divert to DCA, there was no gate that it could park at because the gate space is designed for 737s and similar sized jets.

However, with runways of only 6800', a 747 could land there, but could only take off with enough fuel and passengers to fly to Pittsburgh. Maybe.
 
mlsrar
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RE: Big Planes At DCA

Sat Jul 22, 2000 12:11 am

DLX, the incorporation about the 757s performance was in reference to runway length. PHX, DEN, and SNA all have plenty of length to work with. Humid air might give wings more 'grip' as you say, but the heat is a drag.

When there is excessive heat more fuel and power are drawn from stages 3/4 at the compression point; when combustion is taking place at a higher ambient temperature, less thrust is produced. That's the reason you need a wing design with high-lift in mind for hot-climates, and high-altitudes. That's also why engine thrust is rated in lbs/kN at different temperatures. Go to Kai Tak, watch a notoriously underpowered, fully fueled A340 bound for SFO take off in July. Hear the engines whine, watch the wings flex, and watch as a bent composite metallic shape fights the laws of physics for lift.
I mean, for the right price I’ll fight a lion. - Mike Tyson
 
D L X
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RE: Big Planes At DCA

Sat Jul 22, 2000 12:20 am

SNA's runway is actually much shorter than DCA's and SNA also has that weird noise abatement rule. (The long runway at SNA is only 5700', and they fly 767s out of there daily.) Don't forget that the 757 Commercial Rocket has a VERY high thrust to weight ratio, and very high lift wings (hence their slow cruising speed).

Heat is not a drag, but an air thinner. Humidity is an air thickener. They balance out some.

What I'm saying is that these planes are *designed* for the routes they are flying. You can't stand on the ground and say that a jet is "struggling" or is "having trouble" getting into the air based on the fact that the wings bend, or the plane doesn't lift off until there is only 1000 feet of runway left, etc.
 
exPratt
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RE: Big Planes At DCA

Sat Jul 22, 2000 1:12 am

Who is operating 767s out of SNA? The OAG shows that SNA is served by 737 (many models from -300 and later), 757, MD80, MD90, 320, 319, and CRJ.
 
mlsrar
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RE: Big Planes At DCA

Sat Jul 22, 2000 2:06 am

Well, DLX, the indeniable laws in the physics of combustion will equatorially state that heat has an adverse effect on a turbofan's performance. IT's rather obtuse of you to say that an aircraft never 'struggles' off the ground. Last Thursday, I was returning to MKE via ORD from SNA on N628AA. The aircraft was oversold, had 2 pallets of cargo, a full pax load and was scheduled for meal service. Ambient ground temperature was around 102. As you know, SNA has noise-abatement procedures that are as strict, complex, and quizzical as DCAs are. As usual, the capt. announced over the PA of his intentions of holding the aircraft at full thrust, releasing, a steep ascent, sharp throttle cut-back, half of a split-S curve, dive of 1,000', and return to normal ascent. Other than having used up around 6600' of the aircraft, the plan wasn't followed as it usually was. Normally, AA simply because of the noise abatement, they will NEVER oversell an aircraft leaving SNA, let alone add cargo. In the 32x I've flown on that route, 8x on that particular aircraft, never have we had a takeoff like the aforementioned. We weren't able to take advantage of a rapid ascent, and at full throttle, 400' above the houses on Arcadian avenue, you could see the sunbathers telling us that American was no. 1 with the finger between their index and ring. So, an aircraft can struggle. And, heat has an adverse effect. Heat can either be extremely dry (MEX, PHX, DEN), or humid (BKK, PHK, MIA).
I mean, for the right price I’ll fight a lion. - Mike Tyson
 
D L X
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RE: Big Planes At DCA

Sat Jul 22, 2000 8:04 am

Sure, I'm not arguing that the heat changes the amount of thrust at a particular engine setting. But, don't forget that the humidity of the air has a positive effect on the wing's lift. There's multiple variables to this equation; you can't say that a plane will have more difficulty getting into the air simply because it is hot outside.

And for obtusity, you have taken my comment out of context. Unless you're in the cockpit, you have no way to discern a plane "struggling" to get off the ground, unless you have some different definition of struggle. You have no way to see that the engines are set to the maximum thrust, that the plane will reach Vr before running out of runway, or that the plane even has a positive rate of climb. Even as a passenger, you have little sense of what is really going on because your body is a poor velocitometer. That's why pilots have instrument ratings, because the body lies.

Sure, planes are capable of struggling if poor planning, pilot error, or malfunction occurs. But, you and your fellow passengers or spotters would probably not know the truth if you were relying on your senses for answers.

I'm just annoyed from hearing people say things like "my plane was struggling to get off the ground" simply because they hear the engines rev up high or most of the runway is used.

 
D L X
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RE: Big Planes At DCA

Sat Jul 22, 2000 8:10 am

BTW, what do you mean by 6600' of aircraft? SUrely this is just a typo, but since the runway is only 5700' long, I'm not sure what you were trying to refer to.

And DCA's approach it totally blown out of proportion by people on this forum simply because it has a turn in it. People are not used to turning on final, so it must be dangerous, right?  
 
N202PA
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RE: Big Planes At DCA

Sat Jul 22, 2000 8:54 am

I think people refer to DCA's North approach as dangerous because it forces pilots to shoot a very narrow turn and slide in between two areas of highly restricted airspace (the Pentagon and the White House). Not to mention that aircraft flying it must avoid the Washington Monument and the many high-rise office buildings in Rosslyn. The spotters on Gravelly Point, which is just yards from the end of rwy. 36, don't help either, I imagine.

It's a very challenging approach, because it's a somewhat heavy bank to final on 18, and if you turn too late, you'll have to go around. And then, of course, you have to monitor your height perfectly, and hope to God you don't get any low-level wind gusts or wind shear. It's an approach that many a skilled pilot makes every day, but it ain't a piece of cake for most of 'em. Witness my last flight into DCA, on a hot, hazy June afternoon, in which the pilot of our Continental MD-82 had to battle a bit of somewhat unstable air just as we hit the Potomac River. The wings banked left to right and back at least ten to fifteen times, and when it was time, he turned a hair too late so that we had to go heavier on the bank than normal. Touchdown was simple, but it was a bit of a brow-wiper for the inexperienced passengers on board.

Not that I mind flying into DCA on this approach--I love it, actually!  DCA is definitely *the* most fun airport to land at, even if you're using the South approach.

And for those of you who contine to delude yourselves--anything bigger than a 767-200 will never see scheduled service into DCA. This is a fact.
 
777gk
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RE: Big Planes At DCA

Sat Jul 22, 2000 9:20 am

After a long intercontinental run, a Boeing 747 could technically land at DCA, provided that the weather is at around 65 degrees Fahrenheit, and humidity is under 55%. However, this 747 would be required to use full flaps and slats on the final, and engine power would definitely have to be set under 30% of N1 from 1000 feet to the deck. As soon as the aircraft touches down, which would have to be exactly on the threshold, or the pilot would find himself in the Potomac, full reverse thrust is necessary. After reverse thrust is applied, spoilers would be deployed as well as full brake, as Boeing 747 wheels do not lock up. Reverse thrust is applied until the aircraft reaches a ground speed of 30kts, and spoilers are stowed until the aircraft has reached the turnoff. Brakes are released, and the aircraft resumes regular power to idle ground thrust.

Once on the taxiway, well, that's another story.
 
Purdue Arrow
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RE: Big Planes At DCA

Sat Jul 22, 2000 9:34 am

I read several comments by DLX that seem to say that high humidity improves performance... this is not so. High humidity increases density altitude, which in turn degrades aircraft performance. In my Aviation Meteorology class (ATMS315), we had an equation to determine the effect of high humidity on performance; unfortunately, I don't have it right now because my stuff from that class is in Indiana still, while I am at home in California.
 
Peter
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RE: Big Planes At DCA

Sat Jul 22, 2000 10:01 am

Its too bad the runways are too short for larger planes. It really is a great location. I don't think that there is much chance of the runways being extended.
 
777gk
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Oops.. Bit Of A Mistake

Sat Jul 22, 2000 10:20 am



wrote: Me
-------------------------------
...spoilers are stowed until the aircraft has reached the turnoff.


Correction: Spoilers are not stowed until the aircraft has reached the turnoff.
 
Cody
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RE: Big Planes At DCA

Sat Jul 22, 2000 11:22 am

I once saw a DC-10 at Washington National. Also, I believe Eastern did some test runs with the A300 back in the late 70's.
 
AA777
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RE: Big Planes At DCA

Sat Jul 22, 2000 11:36 am

Planes Don't "Stuggle" to get off of the ground, but when a person says that, they mean that the plane, (at least from the collection of data that thier senses brings them) is using VERY High power, that there is limited Runway Space, and that there is also Limited time to which the Plane must reach Vr speed. SO, they believe that the plane is "pushing" its limits, which is usually not at all true. EXaple: Like when you hit "Severe turbulence" the plane is built to handle MUCH more turbulence than what you are probably experiencing... Anyways...just a Thought.
-AA777
 
Kohflot
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RE: Big Planes At DCA

Sat Jul 22, 2000 10:50 pm

There are currently no 767s operated to/from SNA. The largest plane at this point is FedEx's A310. Apparently, they're reinforcing some of the taxiways to accomodate the 767. I think UPS may be the big proponent there, so they can have a 767 stop there from LGB on its way back to SDF.
Ask why..
 
D L X
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N202PA And Purdue Arrow

Sun Jul 23, 2000 12:48 am

Your post is the exact kind of statement that bothers me. I've had many pilots tell me that the approach to DCA simply ain't all that. The shoot isn't that narrow; the turn isn't that close to the ground; the Washington Monument and USA Today buildings are quite far away from the river; the 14th street bridge is short and over half a mile from end of the runway; and windshear is something that all pilots have to be able to deal with at any airport in the country.

Don't take this as being snooty, please, just as facts.

Purdue Arrow since you're in piloting school, please explain desity altitude and the effect on performance. Are we talking about engine or wing performance? Thanks.

As for A300s at DCA, yes it did happen. EA used them on the shuttle every now and then. Remember though, these planes were very lightly loaded with the little fuel necessary for a 200 mile flight, and very little bags and cargo since it was all shuttle passengers on board.
 
AA777
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RE: Big Planes At DCA

Sun Jul 23, 2000 2:05 am

How could DCA handle an A300?? The 767 is the largest plane that can be used there, and the A300 is quite a bit bigger than the 767-200...I didnt think so until this year when I saw an AA767-200 parked next to An A300...then I saw the difference....
-AA777
 
D L X
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A300 At DCA

Sun Jul 23, 2000 7:10 am

Honestly, I don't know how it worked, since I never saw it there. I do know that the terminal layout was much different back in the days of Eastern, and before the new glass marvel was built.
 
Purdue Arrow
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RE: Big Planes At DCA - Density Altitude

Sun Jul 23, 2000 7:31 am

Density altitude is, in basic terms, the altitude that the airplane "thinks" it is at. When air is less dense, aircraft perform worse, so all factors that account for air density must be taken into consideration when determining density altitude. Following are some of the factors that affect this:

-Altitude above sea level - air becomes less dense as you get further up
-Temperature - Warm air is less dense than cool air
-Humidity - Moist air is less dense than dry air
-Atmospheric Pressure - Meteorological conditions can cause air pressure to be higher or lower than "standard", so this must also be considered

It is a combination of factors such as these that determine the density of the air, and, therefore, the performance of the airplane. The wings and engines don't care whether the air is less dense due to elevation or due to temperature; all that matters is that the air is less dense. As such, an increase in humidity causes an increase in density altitude (and a decrease in air density), which deteriorates airplane performance. An increase in multiple factors compounds the effects; just as people talk about "hot and high" operations as being especially bad, so too are hot and humid operations especially bad.

As for whether we are talking about wings or engine, you tell me - it doesn't matter. When the air is less dense, there will be a smaller mass of air in the engines for cumbustion, thereby reducing the output of the engine. When the air is less dense, there is less air flowing over the wing, reducing the pressure difference between the upper and lower surface, decreasing lift. When the air is less dense, there is less air being deflected down from the lower surfrace of the wing, decreasing lift. For all three of the reasons, any factor that increases density altitude will also decrease aircraft performance; regardless of whether the increase in density altitude is due to high elevation, high temperature, low pressure, or high humidity.

Hope this has helped - did I leave anything unanswered?
 
D L X
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RE: Big Planes At DCA

Sun Jul 23, 2000 11:44 am

So you're saying that performance is hindered more at Bangkok than at Phoenix because of the extra humidity? I could have sworn that humidity thickened the air, but hey. I'm only an engineer.  

Evenso, I still stand by my assertion that a 757 has no trouble getting off the ground at DCA. That is a mission it was designed for.
 
Purdue Arrow
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RE: Big Planes At DCA

Sun Jul 23, 2000 12:06 pm

I'm not saying that one place is worse than other, but rather that it is dependant on conditions. Humidity has relatively little effect on performance compared to altitude and temperature, so a high, hot airport is worse than a cool humid one. All I'm saying is that all factors must be considered for density altitude and that, though the performance difference is small, humidity decreases aircraft performance. As I said, my materials from ATMS315 are in my apartment at school, so I don't have the exact information that I learned in front of me. However, humidity raises the virtual temperature and decreases performance.
 
777gk
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RE: AA777

Sun Jul 23, 2000 11:19 pm

Eastern operated Airbus A300B2/B4's I believe. These are significantly smaller and stubbier than the A300-600Rs that American operate. The A300B2/B4 is more like a 767-200 than anything, and the -600R is like a 767-300, but wider. I also remember reading somewhere that the A310 is cleared by the FAA for landings at DCA. If USAirways "new" airline is based out of BWI, I expect that US will replace DCA services with flights out of BWI and have DCA primarily for the Shuttle. That could open up some space for an A310 service to London or Paris. The thing is, not too many airlines fly A310s any more. I remember the days when you could see three or four DL A310s at Shannon.

You do see my point, though, right? The Airbus A310 can basically operate out of the same gates a 757 can,

757 span: 124' 10"
757 length: 155' 3"
757 Tail height: 44' 6"

A310 span: 144'
A310 length: 109' 1"
A310 Tail height 51'10"

and accomodate 40 more people in a widebody.
 
D L X
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RE: Big Planes At DCA

Mon Jul 24, 2000 2:58 am

I have no idea what you mean by US Airways' new airline, but there is no way that they would move ops to BWI from high yield DCA.

Anyways, you simply don't have enough anything to fly widebodies overseas. There isn't enough gate space. That include all the more fuel trucks and baggage carts that would be necessary to load the jet, and also the space inside the terminal to hold that many passengers waiting to board.

Beyond that, the fuel itself is heavy. A widebody loaded for transatlantic (or even transcon) travel has a very heavy load of fuel, and to be cost efficient to allow low fares, would also have a large cargo load. There simply isn't enough runway at DCA to operate these flights. That's why we have Dulles.
 
Guest

DLX

Mon Jul 24, 2000 3:47 am

If your an engineer do yourself a favor and look up some molecular weights. Water vapor weighs less than air. Add water vapor to dry air and the air becomes less dense. If you don't believe me or Purdue Arrow then go ask a pilot if humid air is less dense or more dense than dry air, even a private pilot can tell you the right anwser. Humid air sticks better to the wing, that is the funnest thing I have heard on this post in awhile.
 
tomindc
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RE: Big Planes At DCA

Mon Jul 24, 2000 3:50 am

I don't think EA ever operated A300 on the Shuttle, but they DID have proving runs. As I remember, it was determined that the A300 could land and take off at DCA but could not meet the necessary single engine takeoff requirements due to an emergency. Therefore, from all I know, a widebody has never been used in revenue service from DCA. The UA DC-10 that landed there due to closings at IAD and BWI did not take off with passengers.

The 757 on the other hand easily handles DCA, using about half the runway whereas the 727 uses almost all --- at least from the visual perspective.

Tom
 
gocaps16
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RE: Big Planes At DCA

Mon Jul 24, 2000 5:21 am

LOL, Are you guys all nuts that you think a 747 can have flights out of DCA or at least a heavy?

Well, sure, if SXM (St Marrtan) could handle, then DCA could...SXM's runway is only around 7,000ft. hehe.

But anyways, The VDOT and the government wouldn't approve the flights..however they were thinking of adding the newer "slots" to LAX, PHX to 767s but they couldn't. THey are 757s.

Yes, The United DC-10 did land at DCA few years back...I was living here near DC when it happened along the Potomac near Rosslyn. It did park but at a remote space.
And yea, that's why we have Dulles...but I don't like it cause it's a half hours drive from here.  

Gocaps!!
 
D L X
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C172sb

Mon Jul 24, 2000 6:26 am

Whoa, slow down there man. Why the venom? I thought I had made it clear that I was ceding to the pilot on this thread (and this forum). I guess I'll have to be more clear so you understand:

"So you're saying that performance is hindered more at Bangkok than at Phoenix because of the extra humidity? [That's interesting, and I guess I was wrong.] I could have sworn that humidity thickened the air, but hey. I'm only an engineer [and not a pilot]."


Is that apologetic enough?


 
Guest

RE: C172sb

Mon Jul 24, 2000 7:21 am

Humid air less dense than dry, remember that and you will be good to go. If air is less dense, takeoff airspeed is higher. True airspeed is higher but not indicated airspeed, the airspeed indicator in the aircraft basically measures the amount of air molecules hitting it. The less dense the air is, the faster the aircraft will have to go to achieve the same takeoff speed in more dense air. Compared to altitude and temperature, as mentioned earlier, humidity has little effect on performance.

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