Airport
An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports often have facilities to store and maintain aircraft, and a control tower. An airport consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface such as a runway for a plane to take off or a helipad, and often includes adjacent utility buildings such as control towers, hangars and terminals. Larger airports may have fixed-base operator services, airport aprons, taxiway bridges, air traffic control centres, passenger facilities such as restaurants and lounges, and emergency services.
An airport with a helipad for rotorcraft but no runway is called a heliport. An airport for use by seaplanes and amphibious aircraft is called a seaplane base. Such a base typically includes a stretch of open water for takeoffs and landings, and seaplane docks for tying-up.
An international airport has additional facilities for customs and passport control as well as incorporating all of the aforementioned elements above. Such airports rank among the most complex and largest of all built typologies with 15 of the top 50 buildings by floor area being airport terminals.
Management
Smaller or less-developed airports, which represent the vast majority, often have a single runway shorter than 1,000 m (3,300 ft). Larger airports for airline flights generally have paved runways 2,000 m (6,600 ft) or longer. Many small airports have dirt, grass, or gravel runways, rather than asphalt or concrete. Skyline Airport in Inkom, Idaho has a runway that is only 122 m (400 ft) long.
In the United States, the minimum dimensions for dry, hard landing fields are defined by the FAR Landing And Takeoff Field Lengths. These include considerations for safety margins during landing and takeoff. Heavier aircraft require longer runways.
The longest public-use runway in the world is at Qamdo Bamda Airport in China. It has a length of 5,500 m (18,045 ft). The world’s widest paved runway is at Ulyanovsk Vostochny Airport in Russia and is 105 m (344 ft) wide.
As of 2009, the CIA stated that there were approximately 44,000 “… airports or airfields recognizable from the air” around the world, including 15,095 in the US, the US having the most in the world.
Airport ownership and operation
Most of the world’s airports are owned by local, regional, or national government bodies who then lease the airport to private corporations who oversee the airport’s operation. For example, in the United Kingdom the state-owned British Airports Authority originally operated eight of the nation’s major commercial airports – it was subsequently privatized in the late 1980s, and following its takeover by the Spanish Ferrovial consortium in 2006, has been further divested and downsized to operating just Heathrow now. Germany’s Frankfurt Airport is managed by the quasi-private firm Fraport. While in India GMR Group operates, through joint ventures, Indira Gandhi International Airport and Rajiv Gandhi International Airport. Bengaluru International Airport and Chhatrapati Shivaji International Airport are controlled by GVK Group. The rest of India’s airports are managed by the Airports Authority of India. In Pakistan nearly all civilian airports are owned and operated by the Pakistan Civil Aviation Authority except for Sialkot International Airport which has a distinctions of being the first privately owned public airport in Pakistan and South Asia.
In the United States commercial airports are generally operated directly by government entities or government-created airport authorities (also known as port authorities), such as the Los Angeles World Airports authority that oversees several airports in the Greater Los Angeles area, including Los Angeles International Airport.
In Canada, the federal authority, Transport Canada, divested itself of all but the remotest airports in 1999/2000. Now most airports in Canada are owned and operated by individual legal authorities or are municipally owned.
Many U.S. airports still lease part or all of their facilities to outside firms, who operate functions such as retail management and parking. In the U.S., all commercial airport runways are certified by the FAA under the Code of Federal Regulations Title 14 Part 139, “Certification of Commercial Service Airports” but maintained by the local airport under the regulatory authority of the FAA.
Despite the reluctance to privatize airports in the US (despite the FAA sponsoring a privatization program since 1996), the government-owned, contractor-operated (GOCO) arrangement is the standard for the operation of commercial airports in the rest of the world.
Landside and airside areas
Airports are divided into landside and airside areas. The landside area is open to the public, while access to the airside area is tightly controlled. The airside area includes all parts of the airport around the aircraft, and the parts of the buildings that are only accessible to passengers and staff. Passengers and staff must be checked by security before being permitted to enter the airside area. Conversely, passengers arriving from an international flight must pass through border control and customs to access the landside area, where they can exit the airport. Many major airports will issue a secure keycard called an airside pass to employees, as some roles require employees to frequently move back and forth between landside and airside as part of their duties.
Facilities
A terminal is a building with passenger facilities. Small airports have one terminal. Large ones often have multiple terminals, though some large airports like Amsterdam Airport Schiphol still have one terminal. The terminal has a series of gates, which provide passengers with access to the plane.
The following facilities are essential for departing passengers:
Check-in facilities, including a baggage drop-off
Security clearance gates
Passport control (for some international flights)
Gates
Waiting areas
The following facilities are essential for arriving passengers:
Passport control (international arrivals only)
Baggage reclaim facilities, often in the form of a carousel
Customs (international arrivals only)
A landside meeting place
For both sets of passengers, there must be a link between the passenger facilities and the aircraft, such as jet bridges or airstairs. There also needs to be a baggage handling system, to transport baggage from the baggage drop-off to departing planes, and from arriving planes to the baggage reclaim.
The area where the aircraft park to load passengers and baggage is known as an apron or ramp (or incorrectly, “the tarmac”).
Airports with international flights have customs and immigration facilities. However, as some countries have agreements that allow travel between them without customs and immigrations, such facilities are not a definitive need for an international airport. International flights often require a higher level of physical security, although in recent years, many countries have adopted the same level of security for international and domestic travel.
“Floating airports” are being designed which could be located out at sea and which would use designs such as pneumatic stabilized platform technology.
Airport security
Airport security normally requires baggage checks, metal screenings of individual persons, and rules against any object that could be used as a weapon. Since the September 11 attacks and the Real ID Act of 2005, airport security has dramatically increased and got tighter and stricter than ever before.
Products and services
Most major airports provide commercial outlets for products and services. Most of these companies, many of which are internationally known brands, are located within the departure areas. These include clothing boutiques and restaurants and in the US amounted to $4.2 billion in 2015. Prices charged for items sold at these outlets are generally higher than those outside the airport. However, some airports now regulate costs to keep them comparable to “street prices”. This term is misleading as prices often match the manufacturers’ suggested retail price (MSRP) but are almost never discounted.
Apart from major fast food chains, some airport restaurants offer regional cuisine specialties for those in transit so that they may sample local food or culture without leaving the airport.
Some airport structures include on-site hotels built within or attached to a terminal building. Airport hotels have grown popular due to their convenience for transient passengers and easy accessibility to the airport terminal. Many airport hotels also have agreements with airlines to provide overnight lodging for displaced passengers.
Major airports in such countries as Russia and Japan offer miniature sleeping units within the airport that are available for rent by the hour. The smallest type is the capsule hotel popular in Japan. A slightly larger variety is known as a sleep box. An even larger type is provided by the company YOTEL.
Premium and VIP services
Airports may also contain premium and VIP services. The premium and VIP services may include express check-in and dedicated check-in counters. These services are usually reserved for First and Business class passengers, premium frequent flyers, and members of the airline’s clubs. Premium services may sometimes be open to passengers who are members of a different airline’s frequent flyer program. This can sometimes be part of a reciprocal deal, as when multiple airlines are part of the same alliance, or as a ploy to attract premium customers away from rival airlines.
Sometimes these premium services will be offered to a non-premium passenger if the airline has made a mistake in handling of the passenger, such as unreasonable delays or mishandling of checked baggage.
Airline lounges frequently offer free or reduced cost food, as well as alcoholic and non-alcoholic beverages. Lounges themselves typically have seating, showers, quiet areas, televisions, computer, Wi-Fi and Internet access, and power outlets that passengers may use for their electronic equipment. Some airline lounges employ baristas, bartenders and gourmet chefs.
Airlines sometimes operate multiple lounges within the one airport terminal allowing ultra-premium customers, such as first class customers, additional services, which are not available to other premium customers. Multiple lounges may also prevent overcrowding of the lounge facilities.
Cargo and freight service
In addition to people, airports move cargo around the clock. Cargo airlines often have their own on-site and adjacent infrastructure to transfer parcels between ground and air.
Cargo Terminal Facilities are areas where international airports export cargo has to be stored after customs clearance and prior to loading on the aircraft. Similarly import cargo that is offloaded needs to be in bond before the consignee decides to take delivery. Areas have to be kept aside for examination of export and import cargo by the airport authorities. Designated areas or sheds may be given to airlines or freight forward ring agencies.
Every cargo terminal has a landside and an airside. The landside is where the exporters and importers through either their agents or by themselves deliver or collect shipments while the airside is where loads are moved to or from the aircraft. In addition cargo terminals are divided into distinct areas – export, import and interline or transshipment.
Access and onward travel
Airports require parking lots, for passengers who may leave the cars at the airport for a long period of time. Large airports will also have car rental firms, taxi ranks, bus stops and sometimes a train station.
Many large airports are located near railway trunk routes for seamless connection of multimodal transport, for instance Frankfurt Airport, Amsterdam Airport Schiphol, London Heathrow Airport, Tokyo Haneda Airport, Tokyo Narita Airport, London Gatwick Airport and London Stansted Airport. It is also common to connect an airport and a city with rapid transit, light rail lines or other non-road public transport systems. Some examples of this would include the AirTrain JFK at John F. Kennedy International Airport in New York, Link Light Rail that runs from the heart of downtown Seattle to Seattle–Tacoma International Airport, and the Silver Line T at Boston’s Logan International Airport by the Massachusetts Bay Transportation Authority (MBTA). Such a connection lowers risk of missed flights due to traffic congestion. Large airports usually have access also through controlled-access highways (‘freeways’ or ‘motorways’) from which motor vehicles enter either the departure loop or the arrival loop.
Internal transport
The distances passengers need to move within a large airport can be substantial. It is common for airports to provide moving walkways, buses, and rail transport systems. Some airports like Hartsfield–Jackson Atlanta International Airport and London Stansted Airport have a transit system that connects some of the gates to a main terminal. Airports with more than one terminal have a transit system to connect the terminals together, such as John F. Kennedy International Airport, Mexico City International Airport and London Gatwick Airport.
Airport operations
There are three types of surface that aircraft operate on:
Runways, for takeoff and landing
Taxiways, where planes “taxi” (transfer to and from a runway)
Apron or ramp: a large concrete surface where planes are parked, loaded, unloaded or refuelled
Air traffic control
Air traffic control (ATC) is the task of managing aircraft movements and making sure they are safe, orderly and free of delays. At the largest airports, air traffic control is a series of highly complex operations that requires managing frequent traffic that moves in all three dimensions.
A “towered” or “controlled” airport has a control tower where the air traffic controllers are based. Pilots are required to maintain two-way radio communication with the controllers, and to acknowledge and comply with their instructions. A “non-towered” airport has no operating control tower and therefore two-way radio communications are not required, though it is good operating practice for pilots to transmit their intentions on the airport’s common traffic advisory frequency (CTAF) for the benefit of other aircraft in the area. The CTAF may be a Universal Integrated Community (UNICOM), MULTICOM, Flight Service Station (FSS), or tower frequency.
The majority of the world’s airports are small facilities without a tower. Not all towered airports have 24/7 ATC operations. In those cases, non-towered procedures apply when the tower is not in use, such as at night. Non-towered airports come under area (en-route) control. Remote and virtual tower (RVT) is a system in which ATC is handled by controllers who are not present at the airport itself.
Air traffic control responsibilities at airports are usually divided into at least two main areas: ground and tower, though a single controller may work both stations. The busiest airports also have clearance delivery, apron control, and other specialized ATC stations.
Ground Control is responsible for directing all ground traffic in designated “movement areas”, except the traffic on runways. This includes planes, baggage trains, snowplows, grass cutters, fuel trucks, stair trucks, airline food trucks, conveyor belt vehicles and other vehicles. Ground Control will instruct these vehicles on which taxiways to use, which runway they will use (in the case of planes), where they will park, and when it is safe to cross runways. When a plane is ready to takeoff it will stop short of the runway, at which point it will be turned over to Tower Control. After a plane has landed, it will depart the runway and be returned to Ground Control.
Tower Control controls aircraft on the runway and in the controlled airspace immediately surrounding the airport. Tower controllers may use radar to locate an aircraft’s position in three-dimensional space, or they may rely on pilot position reports and visual observation. They coordinate the sequencing of aircraft in the traffic pattern and direct aircraft on how to safely join and leave the circuit. Aircraft which are only passing through the airspace must also contact Tower Control in order to be sure that they remain clear of other traffic.
Traffic pattern
At all airports the use of a traffic pattern (often called a traffic circuit outside the U.S.) is possible. They may help to assure smooth traffic flow between departing and arriving aircraft. There is no technical need within modern aviation for performing this pattern, provided there is no queue. And due to the so-called SLOT-times, the overall traffic planning tend to assure landing queues are avoided. If for instance an aircraft approaches runway 17 (which has a heading of approx. 170 degrees) from the north (coming from 360/0 degrees heading towards 180 degrees), the aircraft will land as fast as possible by just turning 10 degrees and follow the glidepath, without orbit the runway for visual reasons, whenever this is possible. For smaller piston engined airplanes at smaller airfields without ILS equipment, things are very different though.
Generally, this pattern is a circuit consisting of five “legs” that form a rectangle (two legs and the runway form one side, with the remaining legs forming three more sides). Each leg is named (see diagram), and ATC directs pilots on how to join and leave the circuit. Traffic patterns are flown at one specific altitude, usually 800 or 1,000 ft (244 or 305 m) above ground level (AGL). Standard traffic patterns are left-handed, meaning all turns are made to the left. One of the main reason for this is that pilots sit on the left side of the airplane, and a Left-hand patterns improves their visibility of the airport and pattern. Right-handed patterns do exist, usually because of obstacles such as a mountain, or to reduce noise for local residents. The predetermined circuit helps traffic flow smoothly because all pilots know what to expect, and helps reduce the chance of a mid-air collision.
At extremely large airports, a circuit is in place but not usually used. Rather, aircraft (usually only commercial with long routes) request approach clearance while they are still hours away from the airport, often before they even take off from their departure point. Large airports have a frequency called Clearance Delivery which is used by departing aircraft specifically for this purpose. This then allows aircraft to take the most direct approach path to the runway and land without worrying about interference from other aircraft. While this system keeps the airspace free and is simpler for pilots, it requires detailed knowledge of how aircraft are planning to use the airport ahead of time and is therefore only possible with large commercial airliners on pre-scheduled flights. The system has recently become so advanced that controllers can predict whether an aircraft will be delayed on landing before it even takes off; that aircraft can then be delayed on the ground, rather than wasting expensive fuel waiting in the air.
Navigational aids
There are a number of aids available to pilots, though not all airports are equipped with them. A visual approach slope indicator (VASI) helps pilots fly the approach for landing. Some airports are equipped with a VHF omnidirectional range (VOR) to help pilots find the direction to the airport. VORs are often accompanied by a distance measuring equipment (DME) to determine the distance to the VOR. VORs are also located off airports, where they serve to provide airways for aircraft to navigate upon. In poor weather, pilots will use an instrument landing system (ILS) to find the runway and fly the correct approach, even if they cannot see the ground. The number of instrument approaches based on the use of the Global Positioning System (GPS) is rapidly increasing and may eventually be the primary means for instrument landings.
Larger airports sometimes offer precision approach radar (PAR), but these systems are more common at military air bases than civilian airports. The aircraft’s horizontal and vertical movement is tracked via radar, and the controller tells the pilot his position relative to the approach slope. Once the pilots can see the runway lights, they may continue with a visual landing.
Taxiway signs
Airport guidance signs provide direction and information to taxiing aircraft and airport vehicles. Smaller aerodromes may have few or no signs, relying instead on diagrams and charts.
Lighting
Many airports have lighting that help guide planes using the runways and taxiways at night or in rain or fog.
On runways, green lights indicate the beginning of the runway for landing, while red lights indicate the end of the runway. Runway edge lighting consists of white lights spaced out on both sides of the runway, indicating the edge. Some airports have more complicated lighting on the runways including lights that run down the centerline of the runway and lights that help indicate the approach (an approach lighting system, or ALS). Low-traffic airports may use pilot controlled lighting to save electricity and staffing costs.
Along taxiways, blue lights indicate the taxiway’s edge, and some airports have embedded green lights that indicate the centerline.
Weather observations
Weather observations at the airport are crucial to safe takeoffs and landings. In the US and Canada, the vast majority of airports, large and small, will either have some form of automated airport weather station, whether an AWOS, ASOS, or AWSS, a human observer or a combination of the two. These weather observations, predominantly in the METAR format, are available over the radio, through automatic terminal information service (ATIS), via the ATC or the flight service station.
Planes take-off and land into the wind in order to achieve maximum performance. Because pilots need instantaneous information during landing, a windsock is also kept in view of the runway. Aviation windsocks are made with lightweight material, withstand strong winds and are lit up after dark or in foggy weather. Because visibility of windsocks is limited, often multiple glow-orange windsocks are placed on both sides of the runway.
Airport ground crew (Ground Handling)
Most airports have groundcrew handling the loading and unloading of passengers, crew, baggage and other services. Some groundcrew are linked to specific airlines operating at the airport.
Many ground crew at the airport work at the aircraft. A tow tractor pulls the aircraft to one of the airbridges, The ground power unit is plugged in. It keeps the electricity running in the plane when it stands at the terminal. The engines are not working, therefore they do not generate the electricity, as they do in flight. The passengers disembark using the airbridge. Mobile stairs can give the ground crew more access to the aircraft’s cabin. There is a cleaning service to clean the aircraft after the aircraft lands. Flight catering provides the food and drinks on flights. A toilet waste truck removes the human waste from the tank which holds the waste from the toilets in the aircraft. A water truck fills the water tanks of the aircraft. A fuel transfer vehicle transfers aviation fuel from fuel tanks underground, to the aircraft tanks. A tractor and its dollies bring in luggage from the terminal to the aircraft. They also carry luggage to the terminal if the aircraft has landed, and is being unloaded. Hi-loaders lift the heavy luggage containers to the gate of the cargo hold. The ground crew push the luggage containers into the hold. If it has landed, they rise, the ground crew push the luggage container on the hi-loader, which carries it down. The luggage container is then pushed on one of the tractors dollies. The conveyor, which is a conveyor belt on a truck, brings in the awkwardly shaped, or late luggage. The airbridge is used again by the new passengers to embark the aircraft. The tow tractor pushes the aircraft away from the terminal to a taxi area. The length of time an aircraft remains on the ground in between consecutive flights is known as “turnaround time”. Airlines pay great attention to minimizing turnaround times in an effort to keep aircraft utilization (flying time) high, with times scheduled as low as 25 minutes for jet aircraft operated by low-cost carriers on narrow-body aircraft.
Safety management
Air safety is an important concern in the operation of an airport, and almost every airfield includes equipment and procedures for handling emergency situations. Airport crash tender crews are equipped for dealing with airfield accidents, crew and passenger extractions, and the hazards of highly flammable aviation fuel. The crews are also trained to deal with situations such as bomb threats, hijacking, and terrorist activities.
Hazards to aircraft include debris, nesting birds, and reduced friction levels due to environmental conditions such as ice, snow, or rain. Part of runway maintenance is airfield rubber removal which helps maintain friction levels. The fields must be kept clear of debris using cleaning equipment so that loose material does not become a projectile and enter an engine duct (see foreign object damage). In adverse weather conditions, ice and snow clearing equipment can be used to improve traction on the landing strip. For waiting aircraft, equipment is used to spray special deicing fluids on the wings.
Many airports are built near open fields or wetlands. These tend to attract bird populations, which can pose a hazard to aircraft in the form of bird strikes. Airport crews often need to discourage birds from taking up residence.
Some airports are located next to parks, golf courses, or other low-density uses of land. Other airports are located near densely populated urban or suburban areas.
An airport can have areas where collisions between aircraft on the ground tend to occur. Records are kept of any incursions where aircraft or vehicles are in an inappropriate location, allowing these “hot spots” to be identified. These locations then undergo special attention by transportation authorities (such as the FAA in the US) and airport administrators.
During the 1980s, a phenomenon known as microburst became a growing concern due to aircraft accidents caused by microburst wind shear, such as Delta Air Lines Flight 191. Microburst radar was developed as an aid to safety during landing, giving two to five minutes’ warning to aircraft in the vicinity of the field of a microburst event.
Some airfields now have a special surface known as soft concrete at the end of the runway (stopway or blastpad) that behaves somewhat like styrofoam, bringing the plane to a relatively rapid halt as the material disintegrates. These surfaces are useful when the runway is located next to a body of water or other hazard, and prevent the planes from overrunning the end of the field.
Airports often have on-site firefighters to respond to emergencies. These use specialized vehicles, known as airport crash tenders.
Environmental concerns and sustainability
Aircraft noise is a major cause of noise disturbance to residents living near airports. Sleep can be affected if the airports operate night and early morning flights. Aircraft noise not only occurs from take-off and landings, but also ground operations including maintenance and testing of aircraft. Noise can have other noise health effects. Other noise and environmental concerns are vehicle traffic causing noise and pollution on roads leading the airport.
The construction of new airports or addition of runways to existing airports, is often resisted by local residents because of the effect on countryside, historical sites, local flora and fauna. Due to the risk of collision between birds and aircraft, large airports undertake population control programs where they frighten or shoot birds.
The construction of airports has been known to change local weather patterns. For example, because they often flatten out large areas, they can be susceptible to fog in areas where fog rarely forms. In addition, they generally replace trees and grass with pavement, they often change drainage patterns in agricultural areas, leading to more flooding, run-off and erosion in the surrounding land.
Some of the airport administrations prepare and publish annual environmental reports in order to show how they consider these environmental concerns in airport management issues and how they protect environment from airport operations. These reports contain all environmental protection measures performed by airport administration in terms of water, air, soil and noise pollution, resource conservation and protection of natural life around the airport.
A growing number of airports are installing solar photovoltaic arrays to offset their electricity use. The National Renewable Energy Lab has shown this can be done safely.
The world’s first airport to be fully powered by solar energy is located at Kochi, India. Another airport known for considering environmental parameters is the Seymour Airport at Galapagos Islands.
Military airbase
An airbase, sometimes referred to as an air station or airfield, provides basing and support of military aircraft. Some airbases, known as military airports, provide facilities similar to their civilian counterparts. For example, RAF Brize Norton in the UK has a terminal which caters to passengers for the Royal Air Force’s scheduled TriStar flights to the Falkland Islands. Some airbases are co-located with civilian airports, sharing the same ATC facilities, runways, taxiways and emergency services, but with separate terminals, parking areas and hangars. Bardufoss Airport, Bardufoss Air Station in Norway and Pune Airport in India are examples of this.
An aircraft carrier is a warship that functions as a mobile airbase. Aircraft carriers allow a naval force to project air power without having to depend on local bases for land-based aircraft. After their development in World War I, aircraft carriers replaced the battleship as the centrepiece of a modern fleet during World War II.
Source from Wikipedia