airstrip n : an airfield without normal airport facilities [syn: flight strip, landing strip, strip]

English

Noun

1. An aircraft landing field, usually with only one runway and basic facilities.

   The outfitter deposited us at a small airstrip out in the bush, promising to pick us up again in a week's time.

See also

• airfield
• airpark
• airport
• landing strip

An airport is a facility where aircraft such as airplanes, helicopters, and blimps take off and land. Aircraft may also be stored or maintained at an airport. An airport consists of at least one surface such as a runway, a helipad, or water for takeoffs and landings, and often includes buildings such as hangars and terminal buildings.

Larger airports may have a variety of facilities and infrastructure, including fixed base operator services, seaplane docks and ramps, air traffic control, passenger facilities such as restaurants and lounges, and emergency services. A military airport is known as an airbase or air station. The terms airfield, airstrip, and aerodrome may also be used to refer to airports, and the terms heliport, seaplane base, and STOLport refer to airports dedicated exclusively to helicopters, seaplanes, or short takeoff and landing aircraft. In some jurisdictions, the term airport is used where the facility is licensed as such by the relevant government organization (e.g. Federal Aviation Administration (FAA), Transport Canada). Elsewhere the distinction is merely one of general appearance. Yet other areas define an airport by its having the necessary customs offices etc expected of a port, though the more general term is airport of entry.

Attributes

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.

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 Bangda Airport, in Bangda, Chamdo, Tibet Autonomous Region. It has a length of 5,500 m (18,045 ft). The world's widest paved runway is at Ulyanovsk Vostochny Airport and is 105 m (344 ft) wide.

As of 2006, there were approximately 49,000 airports around the world, including 14,858 in the US.

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, BAA Limited (BAA) operates seven of the commercial airports in the United Kingdom, as well as several other airports outside of the UK. Germany's Frankfurt Airport is managed by the quasi-private firm Fraport.

In the US and Canada, commercial airports are generally operated directly by government entities or government-created airport authorities (also known as port authorities).

Many US airports still lease part or all of their facilities to outside firms, who operate functions such as retail management and parking. In the US, all commercial airport runways are certified by the FAA, 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.

In New Zealand, Auckland International Airport, the nation's main international airport, is fully privatised. Ownership and operation of the 1,497 hectare complex is vested entirely with Auckland International Airport Limited, a public company, with the only governmental involvement being Airways Corporation of New Zealand's operation of air traffic control systems. Similar arrangements pertain to Wellington and Christchurch airports, and most other main airports are operated by private companies.

In Argentina, 32 airports including the main airport Ministro Pistarini International Airport are operated by Aeropuertos Argentina 2000, a private company. On the other hand, 3 airports are operated by another company named London Supply.

Airport structures

Airports are divided into landside and airside areas. Landside areas include parking lots, public transportation train stations, tank farms and access roads. Airside areas include all areas accessible to aircraft, including runways, taxiways, ramps and tank farms. Access from landside areas to airside areas is tightly controlled at most airports. Passengers on commercial flights access airside areas through terminals, where they can purchase tickets, clear security, check or claim luggage and board aircraft through gates. The waiting areas which provide passenger access to aircraft are typically called concourses, although this term is often used interchangeably with terminal.

The area where aircraft park next to a terminal to load passengers and baggage is known as a ramp (or, to the media and uninitiated, "the tarmac"). Parking areas for aircraft away from terminals are called aprons

Airports can be towered or non-towered, depending on air traffic density and available funds. Due to their high capacity and busy airspace, many international airports have air traffic control located on site.

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.

Modern engineers and architects are developing "floating airports" which could be located several miles at sea and which would use designs such as pneumatic stabilized platform technology.

Shops and food services

Airports have a captive audience, and consequently the prices charged for food are generally higher than are available elsewhere in the region. However, some airports, such as John F. Kennedy International Airport's Terminal 8, have no restaurants at all. Airport fees are fees paid for use of services of airports, such as in the Subic Bay International Airport. However, some airports now regulate food costs to keep them comparable to so-called "street prices". This term is misleading as prices often match the manufacturer's suggested retail price (MSRP) but are almost never discounted.

Premium and VIP services

Several mid-large size airports also have facilities for premium passengers. In the US, these lounges are typically for international or long-haul first and business class passengers, paid members, and elite-level frequent fliers on long haul flights (regardless of what class they are in). In the rest of the world, the lounges are not open to purchase, but can be used by all premium passengers and most elite frequent fliers. Some lounges are comparatively spartan and only offer a quiet place to sit and work; other lounges include meals and massage services.

Cargo and freight services

In addition to people, airports are responsible for moving large volumes of cargo around the clock. Cargo airlines often have their own on-site and adjacent infrastructure to rapidly transfer parcels between ground and air modes of transportation.

Support services

Aircraft maintenance, pilot services, aircraft rental, and hangar rental are most often performed by a fixed base operator (FBO). At major airports, particularly those used as hubs, airlines may operate their own support facilities. Some airports, typically military airbases, have long runways used as emergency landing sites. Many airbases have arresting equipment for fast aircraft, known as arresting gear - a strong cable suspended just above the runway and attached to a hydraulic reduction gear mechanism. Together with the landing aircraft's arresting hook, it is used in situations where the brakes would have little or no effect.

Airport access

Many large airports in the world are located next to or even above railway trunk routes, for instance Frankfurt Airport, Amsterdam Airport Schiphol, London Heathrow Airport, London Gatwick Airport and London Stansted Airport. For local access, many airports have local train lines, rapid transit, light rail lines or other public transport systems, for instance the AirTrain JFK at John F. Kennedy International Airport in New York and the Silver Line T at Boston's Logan International Airport by the Massachusetts Bay Transportation Authority (MBTA). These systems are usually directly connected to the main terminals. Large airports usually have access also through freeways from which cars fed into two access roads, designed as loops, one sitting on top of the other. One level is for departing passengers and the other is for arrivals. This road concept was pioneered at Los Angeles International Airport.

Internal transport

The distances passengers need to move within a large airport can be substantial. It is common for airports to provide moving walkways and buses. The Hartsfield-Jackson Atlanta International Airport has a tram that takes people through the Concourses and Baggage Claim.

History and development

The earliest airplane takeoff and landing sites were grassy fields. The plane could approach at any angle that provided a favorable wind direction. A slight improvement was the dirt-only field, which eliminated the drag from grass. However, these only functioned well in dry conditions. They would eventually be replaced by concrete surfaces that allowed all-weather landings in daylight and at night.

The title of "world's oldest airport" is disputed, but College Park Airport in Maryland, US, established in 1909 by Wilbur Wright, is generally agreed to be the world's oldest continually operating airfield, although it serves only general aviation traffic.

Bremen Airport opened in 1913 and remains in use, although it served as an American military field between 1945 and 1949. Amsterdam Schiphol Airport opened on September 16, 1916 as a military airfield, but only accepted civil aircraft from December 17, 1920, allowing Sydney Airport in Sydney, Australia — which started operations in January 1920 — to claim to be the world's oldest continually operating commercial airport..

The first known usage of the term "airport" appeared in a newspaper article in 1919, in reference to Bader Field in Atlantic City, New Jersey.

Increased aircraft traffic during World War I led to the construction of regular landing fields. Airplanes had to approach these from certain directions. This led to the development of aids for directing the approach and landing slope.

Following the war, some of these military airfields added commercial facilities for handling passenger traffic. One of the earliest such fields was Paris - Le Bourget Airport at Le Bourget, near Paris. The first international airport to open was the Croydon Airport, in South London, although an airport at Hounslow had been temporarily operating as such for nine months. In 1922, the first permanent airport and commercial terminal solely for commercial aviation was built at Königsberg, Germany. The airports of this era used a paved "apron", which permitted night flying as well as landing heavier airplanes.

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, 2001 attacks, airport security has been dramatically increased.

Airport operations

Away from the terminal, there is a large team of people who work to ensure aircraft can land, take off, and move around quickly and safely.

Air traffic control

seealso Air traffic control

The majority of the world's airports are non-towered, with no air traffic control presence. However, at particularly busy airports, or airports with other special requirements, there is an air traffic control (ATC) system whereby controllers (usually ground-based) direct aircraft movements via radio or other communications links. This coordinated oversight facilitates safety and speed in complex operations where traffic moves in all three dimensions. 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, and a wide array of 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 take off 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

All airports use a traffic pattern (often called a traffic circuit outside the U.S.) to assure smooth traffic flow between departing and arriving aircraft. 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 m or 305 m) above ground level (AGL). Standard traffic patterns are left-handed, meaning all turns are made to the left. 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 airplanes 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.

Guidance signs

Airport guidance signs provide direction and information to taxiing aircraft and airport vehicles. Smaller airports may have few or no signs, relying instead on airport diagrams and charts.

There are two classes of signage at airports, with several types of each:

Operational guidance signs

• Location signs - yellow on black background. Identifies the runway or taxiway currently on or entering.
• Direction/Runway Exit signs - black on yellow. Identifies the intersecting taxiways the aircraft is approaching, with an arrow indicating the direction to turn.
• Other - Many airports use conventional traffic signs such as stop and yield signs throughout the airport.

Mandatory instruction signs

Mandatory instruction signs are white on red. They show entrances to runways or critical areas. Vehicles and aircraft are required to stop at these signs until the control tower gives clearance to proceed.

• Runway signs - White on a red. These signs simply identify a runway intersection ahead.
• Frequency Change signs - Usually a stop sign and an instruction to change to another frequency. These signs are used at airports with different areas of ground control.
• Holding Position signs - A single solid yellow bar across a taxiway indicates a position where ground control may require a stop. If two solid yellow bars and two dashed yellow bars are encountered, this indicates a holding position for a runway intersection ahead; runway holding lines must never be crossed without permission. At some airports, a line of red lights across a taxiway is used during low visibility operations to indicate holding positions.

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 take-offs and landings. In the US and Canada, the vast majority of airports, large and small, have some form of automated airport weather station, whether an AWOS, ASOS or AWSS. Most larger airports also have human observers to provide additional observations to supplement the automated station. These weather observations are available over the radio, through Automatic Terminal Information Service (ATIS) or via the ATC.

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.

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. Commercial airfields include one or more emergency vehicles and their crew that are specially 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.

Potential 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 doesn't 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. In the 1980s, a conflict arose in San Jose, California, when a plane attempting to land at Reid-Hillview Airport (built in the 1930s) collided with a Macy's department store at the Eastridge shopping mall. Many local residents tried to get the airport shut down, even though it had been there for fifty years: their neighborhoods (and the mall) were about a decade old.

An airport can have areas where collisions between airplanes on the ground tend to occur. Records are kept of any incursions where airplanes 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 accidents caused by microburst wind shear. (For example, see 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 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.

Airport ground crew

Most airports have ground crew handling the loading and unloading of passengers, crew, baggage and other services. Some ground crew are linked to specific airlines operating at the airport.

Environmental concerns

The traffic generated by airports both in the air and on the surface can be a major source of aviation noise and air pollution which may interrupt nearby residents' sleep and produce other noise health effects. The construction of new airports, or addition of runways to existing airports, is often resisted by local residents because of the effect on the countryside, historical sites, local flora and fauna. Due to the risk of collision between birds and airplanes, 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, because 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 contains 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.

Military airbase

An airbase, sometimes referred to as a military airport or airfield, provides basing and support of military aircraft. Some airbases provide facilities similar to their civilian counterparts. For example, RAF Brize Norton in Oxfordshire, England has a terminal which caters to passengers for the Royal Air Force's scheduled Tristar flights to the Falkland Islands. Military airbases may also be co-located with civilian airports, sharing the same tower/air traffic control facilities, runways, taxiways and emergency services, but with separate terminals, parking areas, hangars and shelter areas. Examples of this are Bardufoss Airport/Bardufoss Air Station and Gardermoen Airport/Gardermoen Air Station, both in Norway. A special variant of a military airfield is the aircraft carrier.

Aircraft carriers

An aircraft carrier is a warship that functions as a floating airport for military aircraft. Aircraft carriers allow a naval force to project air power great distances 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. Unescorted carriers are considered vulnerable to missile or submarine attacks and therefore travel as part of a carrier battle group that includes a wide array of other ships with specific functions.

Airports in entertainment

Airports have played major roles in motion pictures and television programs due to being transportation hubs, but also because of their characteristics. One such example of this is the movie The Terminal, a film about a man who becomes permanently grounded in an airport terminal and must survive only on the food and shelter provided by the airport. Movies such as Airplane!, Airport, Die Hard 2, Soul Plane, Jackie Brown, Get Shorty, Home Alone, Liar Liar, Passenger 57, Final Destination, Unaccompanied Minors, Catch Me if You Can, Rendition and The Langoliers, as well as television series like Lost also have significant parts of their story set within airports.

Several computer simulation games put the player in charge of an airport. These include Airport Tycoon and the sequels; Airport Tycoon 2 and Airport Tycoon 3. There is also a Japanese series of games called Air Traffic Controller.

Airport directories

Each national aviation authority has a source of information about airports in their country. This will contain information on airport height, airport lighting, runway information, communications facilities and frequencies, hours of operation, nearby NAVAIDs and contact information where prior arrangement for landing is necessary.

• AustraliaInformation can be found on-line in the En route Supplement Australia (ERSA) which is published by Airservices Australia, a government owned corporation charged with managing Australian ATC.

• CanadaTwo publications, the Canada Flight Supplement (CFS) and the Water Aerodrome Supplement provides equivalent information.

• EuropeThe European Organisation for the Safety of Air Navigation (EUROCONTROL) provides an Aeronautical Information Publication (AIP), aeronautical charts and NOTAM services for multiple European countries.

• GermanyProvided by the Federal Office for Civil Aviation of Germany.

• FranceAviation Generale Delage edited by Delville and published by Breitling.

• The United Kingdom and the Republic of IrelandThe information is found in Pooley's Flight Guide, a publication compiled with the assistance of the United Kingdom Civil Aviation Authority (CAA). Pooleys also contains information on some continental European airports that are close to Great Britain. National Air Traffic Services, the UK's Air Navigation Service Provider, a public-private partnership also publishes an online AIP for the UK.

• The United StatesThe US uses the Airport/Facility Directory (A/FD), published in seven volumes.

• A comprehensive, consumer/business directory of commercial airports in the world (primarily for airports as businesses, rather than for pilots) is organized by the trade group Airports Council International.

See also

• Domestic airport
• List of airports
• List of aviation topics
• List of hub airports
• Model airport
• NIMBY
• Port
• Regional airport
• Total Airport Management Systems
• World's busiest airport
• Heliport

References

External links

• Airports Council International (ACI) — industry group representing over 1,600 major airports.
• ACI 2006 annual report (PDF) — includes airport traffic information and forecasts.
• International Air Transport Association (IATA) — representing the world's major airlines.
• History of aircraft landing aids
• Visit airports with Google Maps and Google Earth
• Travel information on roughly 150 worldwide airports

nah:Ehēcalquixohuayān