Instead of a few runways in a few directions, why not have a large square block of asphalt so that planes can take off and land in any direction? Where and on what direction planes land and take off will still be determined by ATC, but these decisions are then not bound by the choice of just a few runways. So, there will only be virtual runways and taxiways instead of real physical ones.
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76It looks... expensive. – user3528438 Feb 19 '20 at 16:06
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67What problem is this trying to solve? – MJeffryes Feb 19 '20 at 16:13
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Theoretically, it could be possible a single asphalt block runway. But this would raise numerous safety and security issues in modern aviation. Perhaps too many to be even considered as a feasible alternative. – ppinto Feb 19 '20 at 16:17
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48Danger, chaos, confusion and no clear solution to a problem, whats not to like about this idea? – gwally Feb 19 '20 at 17:35
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5Hydrobases kind of have a single big block (a lake) that is used as a runway. – Manu H Feb 19 '20 at 18:22
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22Even when nature provides us with such a nice flat area, the human tendency is to divide it up into official runways: https://en.wikipedia.org/wiki/Rogers_Dry_Lake – jamesqf Feb 19 '20 at 18:47
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3For the same reason that streets have painted lane markings. – Ralph J Feb 19 '20 at 22:24
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45"Why build roads when you could pave the entire planet, so cars can just drive anywhere. GPS could still send you into the general direction. Virtual roads!" – Num Lock Feb 20 '20 at 06:57
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4I would offer a circular "runfield" as most symmetric solution. It could be painted in concentric and radial patterns and could be made a bit dome-shaped in order to manage the rainwater (somehow). Well, it still won't be any better than the traditional runway and will still be expensive. – fraxinus Feb 20 '20 at 10:06
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@fraxinus Like the one is this question? – PerlDuck Feb 20 '20 at 10:54
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@PerlDuck Not really. The OP here offers a square, I "optimized" his square by cutting edges to make it symmetric and equally "long" in all directions. What you link is a traditional runway, just bent "a little" to meet both ends together. There is no tarmac in the middle and that makes it a little bit more (but still not exactly) possible. – fraxinus Feb 20 '20 at 13:16
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6Where do you propose the ILS goes? On a lazy susan? – J... Feb 20 '20 at 13:32
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Rather than a big square block, how about a circular runway? – user3490 Feb 20 '20 at 16:42
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I'm glad someone fixed the title. – user253751 Feb 20 '20 at 17:12
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1@NumLock - roads are not a good analogy to this since first, covering the planet with roads is impossible, while airports are a finite (though very large) area. And secondly, major airports have a single controlling entity that could control the angle of arrivals/departures while roads have no central controller. Still doesn't make it practical, but it's not comparable to doing it to roads. – Johnny Feb 21 '20 at 01:18
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4Instead of a huge runway with n^2 resource requirements, why not just make the runway rotate? :-D – Michael Feb 21 '20 at 03:30
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1@Michael I wouldn't say it is less expensive, but still done in practice: https://en.wikipedia.org/wiki/Aircraft_carrier. Added bonus: you can run the whole runway at some speed in some direction in order to make a favorable artificial wind. – fraxinus Feb 21 '20 at 10:45
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Presuming everything is automated, this makes sense on the surface, except even humans have no problem as it is. The entire plot would still be made by one, ten-foot-wide, lane at a time creeping inches per minute. And after the first one's done, they say if we just had one more going the other way, it'd be fine. Custom-Configured Cat Paver Helps Contractor Meet Runway Specs – YouTube – Mazura Feb 21 '20 at 20:51
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Where do the runway lights go? – DKNguyen Feb 21 '20 at 23:10
10 Answers
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The typical World War II "A" runway shape solves this issue, without covering a huge amount of area with concrete, etc. Even so, that configuration has fallen out of use in modern airports.
Ultimately, this is a solution to a problem that doesn't really exist and a problem which has a more efficient solution that was already widely used.
With respect to your particular question - to some degree, this is exactly how original grass fields were treated. But no matter how convenient, there's always a need for consistency and predictability and you can see how that has developed to what we have now. Taxiing a heavy airliner isn't a trivial task - doing so with no markings or defined route sounds terrifying.
Additional practical issues of your large slab of concrete vs. a defined runway:
- No ILS
- No runway lighting
- No runway markings
- No threshold, no touchdown markers
- Far more difficult to precisely define runway length
- Very very difficult to accurately describe a particular location and route
To be honest, the list goes on and on and I'd struggle to imagine commercial ops being able to operate like this safely and efficiently.
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49A large slab would also be much harder to check for debris, and much harder to drain. By the time you'd painted enough markings on to keep fast-moving things away from other things, you might as well let the grass grow in between the defined zones – Chris H Feb 19 '20 at 17:17
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4Related:https://aviation.stackexchange.com/questions/1898/could-you-land-a-large-airplane-on-short-circular-runways – 60levelchange Feb 19 '20 at 20:57
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No ILS, but 36 RNAV (or even GLS) approaches would cost less than two ILS approaches anyway. Whether ATC could handle that is another matter. – StephenS Feb 20 '20 at 15:44
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I found the class A airfields (https://en.wikipedia.org/wiki/Class_A_airfield) interesting, it might be worth mentioning. There is a trade-off between any-direction landing and dealing with some crosswind. – Bit Chaser Feb 20 '20 at 17:24
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1Most of the practical issues noted have a common and relatively straightforward solution; embedded, configurable, dynamically controlled lighting. You can paint taxiways, runway markings, touchdown markers, entire runways (dialed to any desired length that will fit within the area), exclusion zones, and so on anywhere you need, as and when needed. Would be incredibly expensive, but certainly doable from a technological standpoint. – aroth Feb 21 '20 at 01:14
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2@aroth Once you've painted something, you now have a defined runway and may aswell have just started with that. I also don't think it's that easy or straightforward - even for something like lighting. – Dan Feb 21 '20 at 08:28
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Adding to the list: snow removal would be a major concern in my location. A single standard runway can require a large maintenance budget, crew, and specialized equipment just for snow removal. – llogan Feb 21 '20 at 20:43
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@aroth Uhhhh where is this dynamic runway lighting supposed to be installed? – DKNguyen Feb 21 '20 at 23:12
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@Dan I should have been more clear. Where I said "paint" I meant "display, using the dynamically controllable lights embedded throughout the concrete surface". Not to literally put actual paint on the thing. DKNguyen - all throughout the surface of the concrete slab. It will be exorbitantly expensive! And since the embedded lights must be clearly visible in broad daylight, the energy usage will be ridiculous, too. But it's technically within the realm of what could be done. :) – aroth Feb 22 '20 at 12:45
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We have runways for the same reasons that we have roads:
- All traffic needs to move in the same direction, in visually easily identifiable lanes. Channeling the traffic improves safety and efficiency.
- All of the area outside the lanes need not be paved. Increases cost efficiency.
- Traffic lanes and runways can be constructed for rainwater run-off, flat fields cannot.
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The 1.5% grade for drainage, that is the severity of grade at which railroad freight trains will be seriously considering adding "helper" engines to assist on the grade. These days they mostly do it for dynamic braking downhill, because locomotives with AC motors and VFD have the low end power to climb them unassisted. – Harper - Reinstate Monica Feb 20 '20 at 03:11
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17@Harper-ReinstateMonica I think you misunderstood the picture: the planes don't move from left to right but from front to rear and don't have to get over a 1.5% gradient. The "bump" is between the left and right main landing gear. ... or maybe I misunderstood your comment. – PerlDuck Feb 20 '20 at 07:08
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Also, aircraft are designed with a substantially higher thrust/tractive effort to weight ratio than trains. 2% slope lengthways seems to be the maximum for commercial runways. – SomeoneSomewhereSupportsMonica Feb 21 '20 at 05:32
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Land costs money and paving it costs money. For a typical commercial airport like Grand Rapids Ford Int'l, your proposed runway would be about 3 square miles, which could easily cost about \$40,000,000 for the land, and another \$20,000,000 to pave it.
Your proposal would have very little benefit; right now, Grand Rapids Ford Int'l has two main runways at a 90-degree angle to each other, meaning that airplanes may have to land at up to a 45 degree angle to the wind. That's almost never a problem.
So your suggestion would cost about $60,000,000 and provide essentially no benefit.
Tanner Swett
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9The land costs are pretty well sunk anyway - there aren't any airports that don't own the land between the runways & taxiways, are there? The paving cost is 100% valid. Oh, and don't forget the expense of maintaining that massive slab o'pavement instead of just "thin" ribbons of pavement. – FreeMan Feb 19 '20 at 21:01
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12@FreeMan Well, generally, building the proposed mega-runway would require either buying some new land, or demolishing lots of existing buildings. In the case of the Grand Rapids airport, it would require demolishing the existing terminal, buying lots of neighboring real estate, demolishing those buildings, and building a new terminal on some of the leftover land. – Tanner Swett Feb 19 '20 at 21:14
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4Think of the drains, too! With hydrocarbon-contaminated runnoff. And on a surface where coeffieient of friction is critical, over three square miles! – Dan Feb 20 '20 at 02:18
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1also, the maintenance... the paved area needs to be maintained as well, the more there is to maintain, the more effort and cost there is – eis Feb 20 '20 at 08:31
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4@FreeMan Most airports use that space to park aircraft and other vehicles, build terminals and cargo handling facilities, office space, warehouses, etc. etc.. You'd need to buy more land to relocate all of that, and have longer distances to cover for the aircraft and other vehicles to get to and from all those new buildings. – jwenting Feb 20 '20 at 11:31
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@FreeMan and a lot of small municpal/regional airports tend to lease the land in between out to farmers for growing crops or hay as well.This helps them recoup some of the cost of the land they have to own, and reduce their maintenance cost as they don't need to maintain that area. – PhilippNagel Feb 20 '20 at 15:15
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@FreeMan In what sense is the land costs sunk? If you are claiming that airports could do this with land they already have, then shouldn't just just assert that? I get the impression you don't fully grasp what "sunk cost" means. – Acccumulation Feb 22 '20 at 08:17
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Airfields used to have that, big fields where the pilots could line up and takeoff or land into the best headwind. Might be okay if the field was small, say up to 3000 feet by 3000 feet.
But, where do you set up ground based instruments that help with poor visibility landings (low ceilings due to fog, rain, etc)? Radio antennas, lights, etc. Having it hard installed/wired is the most feasible and durable.
And then once the runways get longer, the sheer size becomes an issue, along with development that seems to spring up around airports over time.
So the runways are fixed, and we learn how to handle the plane in crosswinds.
CrossRoads
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1Consider that a large commercial airport has 12000ft long 200ft wide runways (about 3.7Km x 60m) not including blast pads and overrun areas. (cheaper pavement as they don't take weight in normal operations and can be inspected/repaired after emergency use) A square would cover 14 square Km or 5.2 sq miles or 3300acres. All at a thickness that can support a hard landing in a fully loaded 747.(about 18-24inches thick of med-high strength concrete with some re-enforcing steel) – Max Power Feb 20 '20 at 09:05
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A large number of answers so far, so I won't cover budgets. But I didn't notice any mention the approach and departure paths. These flight paths must be kept clear of obstacles above a certain geometric plane and the common folk love to purchase land near an airport or race track and then complain about noise so flight paths are designed to minimize trouble with neighbors, also there is risk with a busy airport and aircraft traveling off the ends of the runway. Jet blast also can not be directed at parked planes. Then you have issues with design of instrument flight rules approaches and departures.
Max Power
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4Not to mention that in the less flat parts of the world, those obstacles are often mountains. – jamesqf Feb 20 '20 at 18:03
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In the old days many "taildragger" planes were literally that: the tail dragged on a non-steerable skid. The skid didn't work well for keeping the plane straight on hard pavement. Also some of these planes didn't handle crosswinds well even on grass. So planes took off and landed on wide-open grass fields where pilots were free to take off and land directly into the wind.
Now, almost no planes have tailskids, and most have tricycle gear configurations, and crosswinds are much less of an issue than they used to be. Two runways oriented at near 90 degrees provide an adequate reduction in the crosswind component for most situations. Modern planes, especially airliners, have much heavier "wheel loadings" than the old antiques, and require heavily reinforced pavement. It wouldn't be cost-effective to pave an entire square field or other similar shape in this manner.
Also, as another answer has noted, modern instrument landings and takeoffs need to have elaborate systems to transmit radio beams, along with elaborate lighting systems. If you have such a system, it makes sense to have a runway aligned with it-- though granted, the need for precision would be reduced, as far as maintaining a target course, if you were aiming for a gigantic paved area rather than a runway, and had clearance to land anywhere on it. But if you drifted too far off the intended course, you'd also lose the beam that is giving you vertical guidance, unless the beam is somehow designed to cover a very broad area. Maybe as GPS systems continue to play an ever-more prominent role in instrument landings, the radio beam issue will become less of an obstacle to your idea.
But there are other issues as well. Paving an enormous field also creates environmental problems-- where does the run-off water go? And so on and so forth. On the whole, there is little upside to your idea in the context of modern airline operations, and lots of downside.
quiet flyer
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Previous posters have given reasons not to use your proposal of designing airports as huge square slabs of concrete with no discernible runway for large airports. I don’t think this would be feasible for small airports, either. I have yet to land at a GA airport that took up a perfectly square plot of land. Most airports are long and narrow. The exception is the few airports with runways set up in roughly “A” or triangle shapes. Or, airports set up with two runways at a roughly 90° angle. It is easier to find and buy/procure land for an airport that is longer than it is wide. And, length is important to have distance for takeoff and landing. A 4000 by 1000 foot area would be more useful than a 2000 by 2000 foot area. Plus, you would have more options available geographically. Then, there is also the issue of where to put the necessary facilities like towers, fuel, hangars, FBO, etc. Placing these along one edge of a square limits the use of that edge or axis for flight operations. If you place the facilities in the center, you limit their access by land based traffic.
Dean F.
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Well, there was Black Rock Interstellar, back in the old days (pre-2000 or so), where you could land & take off pretty much any which way. But I understand they've gotten much more officious these days. – jamesqf Feb 20 '20 at 04:08
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2If you place the facilities in the center, you limit their access by land based traffic. Obviously you dig a tunnel underground for routine land vehicle access, because clearly money is no object! But seriously, good point about logistics. You can't just have aircraft land anywhere at any angle if you have terminal buildings in the middle of the square. Although along one side probably makes the most sense. Still lots of room to land beside the terminal, somewhere else along this vast wide area. But then you might have to taxi all the way to/from the far end. – Peter Cordes Feb 20 '20 at 07:45
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Primarily costs. Paved runways cost around $1-2 million per 1000 ft, depending on construction and features. An airport like KATL probably has a quarter of a billion USD invested in the runways, taxiways and reinforced concrete infrastructure alone. In addition if you did make, say, a 2 x 2 mile concrete pad to the standards of a runway, most of this structure would never really get used, making it a colossal waste of money.
Given the high costs and other requirements, it’s easier just to lay out single runways with connecting taxiways and parking aprons.
Romeo_4808N
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Something i havent seen in any other answers, ATC logistics. ATC is already considered one of the worlds most stressful jobs, and planes can only land 2 ways on a particular segment of land (and taxi). What you are proposing is a situation where ATCs have to direct planes to land in a specific spot wothout deviation or they risk a collision, whilst not being able to clearly see half the airspace in due to the sheer distance and lack of distance markings.
This is not including the other logistical problems with taxing due to the lack of taxi ways and more importantly hold points. Without taxi ways and hold points getting taxiing aircraft off one ‘runway’ but not on another and other movement procedures would become much harder. Current systems still use taxiways labeled with a small sign on the grass between runways/taxiways etc. What you are proposing is a system with no markings, or 360 sets of markings so they can rotate the active ‘runways’ directly with the wind.
Oversll the confusion and stress as well as the added cost and logistical problems mentioned in other answers would not be worth the small gain from such an airport.
B-K
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If planes could land from any direction, where could you put the tower? It is higher than the runways, and is an essential part of controlling the movement of planes on ground and in the final stages of take-off, landing, touch-and-go, and other operations.
Other items around an airport like to have elevation, such as radar installations. These would need to respect the flight paths from anywhere to anywhere on the landing plane.
By having specific approach and take-off routes, the region surrounding the runway can be built upon. Otherwise there would be onerous restrictions on development well outside the mega-slab runway.
cmm
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