CrazyInteg

I'm wondering what "airport capacity" actually means. The numbers that are talked about in the newspapers and online articles do not make sense to me. Here is a great example:
https://en.wikipedia.org/wiki/Phuket...tional_Airport

In 2015, Phuket International Airport 12.5 million passengers.
The capacity of the airport is 6.5 million. They are building a new terminal which should open later this year, which will bring the airport capacity up to 12.5 million passengers.

How is this possible? How can they get double the amount of passengers through the airport over what their official capacity is? If the answer is, "oh, that's because XYZ" then why isn't the current capacity 12.5 million and with the expansion the new capacity will be 20 million (or whatever)?

LondonElite

You may be aware that prisons are hopelessly overcrowded as well.

Tchiowa

Number, size of planes and frequency of flights. Add a terminal, gives you more gates so increases the number of people you can accommodate.

Madone59

Have you been to HKT? I'm not surprised it's operating at 2x capacity. That airport is a madhouse.

milepig

There's a distinction between "Functional Capacity" and "Total Capacity."

I'll use an example from another industry. If a warehouse has 500,000 cubic feet of shelving capacity you could theorize that it could hold 500,000 1 cubic foot sized boxes.

But, you need to allow for ebbs and flows. You need to have enough space available in the same spot at the same time to allow storage for a sudden influx of 40,000 identical widgets. It makes no sense to stuff them here and there everywhere there happens to be an empty cubic foot and they try to find them all back later when an order comes in.

I've read that something is functionally full at about 85% of total capacity.

Still doesn't explain the 2x, but I'm thinking people moving about isn't quite the same formula a boxes sitting on pallets on shelves.

groundops

Airports are businesses that sell retail space (airside and landside), runway slots, aircraft parking, landside car parking etc and they generally calculate their charges on SBR (Scheduled Busy Rates) - this is how many passengers they must process an hour (although not all costs are based on this).

Try and fly an aircraft into LHR at 7am on a Monday morning and it will probably cost you more than 11am on a Sunday! Why? Monday at 7am is busier than Sunday at 11am!

Airports do not really care if your airline is like Emirates and has nine check in counters or is some unheard of airline that just has one counter (obviously commercial department prefer the former). If your check in experience is bad that is your problem with your airline! Try another!

They care more about getting you through security and into duty free as they normally gain a commission on any spend you make.

ICAO sets out SBRs that airports should aim for in processing pasengers but I will not divulge these. In general, better airports far exceed these and many "crappier" airports fail to.

Efrem

Roads are designed to carry a certain number of vehicles to keep them all moving at a reasonable pace. That's their "capacity." If more cars than that show up during rush hour, the road can't refuse them*. It's carrying more than its nominal capacity. We get traffic jams that may stretch for miles. As the rush hour winds down and traffic drops to a tolerable level, the jams ease up and the road works well again.

Same with airports. Their "capacity" is the number of passengers they can handle during normal flight hours without undue delays or crowding, however the airport designers defined that. If more flights, people, bags, etc., show up, it gets overcrowded and things slow down - perhaps a lot. Everybody will be out by 2 am, though.

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*A few highways control access via lights during peak periods. Those are an exception.

jrl767

in an operational context it also refers to runway capacity ... Aircraft must be spaced a certain distance apart for safety, and obviously a plane that's just landed must be a certain distance clear of the runway before a departing flight can start takeoff roll ... simultaneous landings on parallel runways are permitted if the runways are far enough apart, where "far enough" varies with weather conditions ... don't have time for more right now

benniefly2

Generically speaking, in ideal conditions, a runway can typically handle one operation per minute. A plane landing is an operation. A plane taking off is an operation. So if an airport in the United States is using two parallel runways, it can bring in and send out 60 planes per hour if the weather is good. If weather is bad or visibility is poor, you need bigger spacing which would lower the number of operations per hour.

Palal

There are various measures of capacity for airports, from runway, to apron to terminal. In this case we're most-likely talking about terminal capacity. For people to comfortably use a terminal you need a certain amount of space per person. LCC terminals usually allot less capacity per person than conventional terminals. Sure, you can have twice the pax a terminal was designed for if you re-configure it, but at some point you'll need to add more terminal space.

jonsg

Don't forget: if your existing terminal's set up for A320s, and the new terminal can handle A380s, you're going to do a lot better than double your capacity!

It's a "how-long-is-a-piece-of-string" question as to how a new terminal affects the airport's peak flows.

Efrem

Au contraire: you may or may not double the terminal's passenger-handling capacity, but you will more than double the number of passengers who are trying to squeeze into that capacity.

CrazyInteg

I appreciate all the answers.

I think what I understand is that an airport's capacity is a theoretical number based on many factors.

jonsg

That rather depends! If you can take as many A380s in T2 as you could A320s in T1 (and if you can turn them around in about the same time - OK, a bit of a stretch), you surely will more than double the capacity!

Efrem

No. This confuses an airport's capacity with the utilization of that capacity. Changes in utilization do not affect capacity.

To take an example in the other direction: Suppose an airport with a capacity of 100,000 passengers/day is closed for a day due to a snowstorm or a hurricane. There are no passengers at all that day. Its capacity does not change; it is still 100,000 passengers/day. Its utilization as a fraction of that capacity drops to zero.

Unless one is concerned with the capacity to fly passengers in and out, which is normally not relevant because it is far higher than the airport's ability to handle passengers on the ground, changing aircraft types will not affect airport capacity. It may affect the utilization of its capacity, but that is not the same thing.