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An 'airliner' is a large fixed-wing aircraft with the primary function of transporting paying passengers. Such aircraft are usually operated by an airline which owns or leases the aircraft.
The official definition of an airliner varies from country to country, but the common definition is an aircraft with seating for 20 or more passengers and/or an empty weight above 22,680 kg (50,000 lb.), with two or more engines.

Contents

History of airliners

Types of airliners

Wide-body jets

Narrow-body jets

Regional airliners

Commuter aircraft

Engines

Airliner variants

Manufacturers

Notable disputes

Famous airliners

Airliner recycling

Cabin configurations

Seats

Overhead bins

Passenger service units

Baggage holds

Narrow-body airliners

Wide-body airliners

See also

External links and references

History of airliners

If an airliner is defined as a plane intended for carrying multiple passengers in commercial service, the Russian Sikorsky Ilya Muromets was the first passenger aircraft. The Ilya Muromets was a luxurious aircraft, it had an isolated passenger saloon, comfortable wicker chairs, bedroom, lounge and even a bathroom. The aircraft also had heating and electrical lighting. On December 10, 1913, the Ilya Muromets was tested in the air for the first time, and on February 25, 1914, took off for its first demonstration flight with 16 passengers aboard. From June 21-June 23, it made a round-trip from St Petersburg to Kiev in 14 hours and 38 minutes with just one landing. If it had not been for World War I, the Ilya Muromets would have probably started passenger flights that same year.
The Ford Trimotor was the second known passenger aircraft. With two engines mounted on the wings and one in the nose and a slabsided body, it carried 8 passengers and was produced from 1925 to 1933. It was used by the predecessor to TWA as well as other airlines long after production ceased. In 1932 the 14 passenger DC-2 flew and in 1935 the more powerful, faster, 21-32 passenger DC-3. DC-3s were produced in quantity for WWII and sold as surplus afterward.
Immediately after World War II, airliners were based on the heavy bombers of the war period.
The first jet airliners came in the immediate post war era. Turbojet engines were trialled on piston engine airframes such as the Avro Lancastrian and the Vickers VC.1 Viking the latter becoming the first jet engined passenger aircraft in April 1948. The first purpose built jet airliners were the de Havilland Comet (UK) and the Avro Jetliner (Canada). The former entered production and service while the latter did not. The Comet was unfortunate in that metal fatigue caused crashes.
Jets did not immediately replace piston engines and many designs used the turboprop rather than the turbojet or the later turbofan engines.

Types of airliners

Wide-body jets

The largest airliners are ''wide-body'' jets. These aircraft are frequently called ''twin-aisle aircraft'' because they generally have two separate aisles running from the front to the back of the passenger cabin. Aircraft in this category are the Boeing 747, Boeing 767, Boeing 777, Airbus A300/A310, Airbus A330, Airbus A340, Airbus A380, Lockheed L-1011 TriStar, McDonnell Douglas DC-10, McDonnell Douglas MD-11, Ilyushin Il-86 and Ilyushin Il-96. These aircraft are usually used for long-haul flights between airline hubs and major cities with many passengers. Future wide-body models include the Boeing 787 and Airbus A350.

Narrow-body jets

A smaller, more common class of airliners are the ''narrow-body'' or ''single aisle'' aircraft. These smaller airliners are generally used for medium-distance flights with fewer passengers than their wide-body counterparts.
Examples include the Boeing 717, 737, 757, McDonnell Douglas DC-9 & MD-80/MD-90 series, Airbus A320 family, Tupolev Tu-204, Tu-214 and Tu-334. Older airliners like the Boeing 707, 727, McDonnell Douglas DC-8, Fokker F70/F100, VC10, Tupolev, and Yakovlev jets also fit into this category.

Regional airliners

''Regional airliners'' typically seat fewer than 100 passengers and may be powered by turbofans or turboprops. These airliners, though smaller than aircraft operated by major airlines, frequently serve customers who expect service similar to that offered by crew on larger aircraft. Therefore, most regional airliners are equipped with lavatories and have a flight attendant to look after the in-flight needs of the passengers.
Typical aircraft in this category are the Embraer ERJ, Bombardier CRJ series and "Q" (DASH-8) series, ATR 42/72 and Saab 340/2000. Airlines and their partners sometimes use these for short flights between small hubs, or for bringing passengers to hub cities where they may board larger aircraft.

Commuter aircraft

Passenger aircraft with 19 or fewer passenger seats are called ''commuter aircraft'' or ''air taxis'', depending on their size, engines, and seating configurations. The Beechcraft 1900, for example, has only 19 seats. Depending on local and national regulations, a commuter aircraft may not qualify as an airliner and may not be subject to the regulations applied to larger aircraft. Members of this class of aircraft normally lack such amenities as lavatories and galleys and typically do not carry a flight attendant.
Other aircraft in this category are the Fairchild Metro, Jetstream 31/41, IPTN CN-235, and Embraer EMB 110 Bandeirante. The Cessna Caravan, a single-engine turboprop, is sometimes used as a small airliner, although many countries stipulate a minimum requirement of two engines for aircraft to be used as airliners.
Twin piston-engined aircraft made by Cessna, Piper, Britten-Norman, and Beechcraft are also in use as commuter aircraft.

Engines

Until the beginning of the jet age, piston engines were common on propliners like the Douglas DC-3. Now nearly all modern airliners are powered by turbine engines, either turbofans or turboprops. Gas turbine engines operate efficiently at much higher altitudes, are far more reliable than piston engines, and produce less vibration and noise. Prior to the jet age it was common for the same or very similar engines to be used in civilian airliners as in military aircraft. In recent years, divergence has occurred so that it is now unusual for the same engine to be used on a military type as a civilian type. Usually military aircraft which share engine technology with airliners are transports or tanker types.

Airliner variants

Some variants of airliners have been developed for carrying freight or for luxury corporate use. Many airliners have also been modified for government use as "VIP" transports and for military functions such as airborne tankers (for example, the Vickers VC-10, Lockheed L1011, Boeing 707), air ambulance (USAF/USN McDonnell-Douglas DC-9), reconnaissance (Embraer ERJ 145, Saab 340, Boeing 737), as well as for troop-carrying roles.

Manufacturers

These include:

★ United States

★
★ Boeing

★
★ Douglas Aircraft Company and later, McDonnell Douglas (now a part of Boeing)

★
★ Lockheed Corporation (now part of Lockheed-Martin, and no longer involved in civil aviation)

★ Canada

★
★ Bombardier (includes the former De Havilland Canada)

★ Brazil

★
★ Embraer

★ Russian companies (formerly Soviet-controlled)

★
★ Tupolev

★
★ Ilyushin

★
★ Antonov (based in Ukraine)

★
★ Sukhoi

★
★ Yakovlev

★ Europe

★
★ Airbus Industrie (formerly a multinational conglomeration of smaller European aerospace companies)

★
★ ATR (France/Italy)

★
★ Fokker (The Netherlands, now defunct)

★
★ SAAB (Sweden)

★
★ Britten-Norman (United Kingdom)

★
★ BAE Systems (United Kingdom)

★
★ Let Kunovice (Czech Republic)
The international market for middle-sized and large-sized airliners is now divided between Airbus and Boeing. Smaller-sized aircraft manufacturers include, in addition to these two, ATR, Embraer and Bombardier.
''(This list may be incomplete.)''

Notable disputes

The large (100 seat or greater) airliner market is dominated by two companies: Airbus, a Western European aviation manufacturer (part of EADS, an aerospace company), and Boeing, based in the United States. With the emergence of Airbus as a competitor to Boeing, both companies, backed by their respective governments (the European Union and European governments on one side, the US government on the other side), have recently been engaged in trade disputes. Each side accuses the other of being unfairly subsidized by their respective governments. Owing to its origin as a combination of state-owned aviation enterprises, Airbus receives a significant portion of its operating budget directly from European governments, ostensibly as loans, but without the obligation to repay them. On the other hand, Boeing gets research and development funding from NASA and the US Department of Defense, tax breaks (which all similar US companies receive), and a large volume of military orders, all of which Airbus views as indirect subsidies.
In addition to their main headquarters in Europe and the United States, both Airbus and Boeing use subcontractors from many countries. For example, Boeing has long had major components built by companies in Japan with various subsystems coming from Europe and Asia. Airbus aircraft are often equipped with engines, auxiliary power units, and electronic systems built in the US. Thus, while both companies may try to present themselves as strictly national entities, the airliners they build are composed of components manufactured across the globe.

Famous airliners

★ The Douglas DC-3 - considered by many to be the first true airliner

★ The triple-tailed Lockheed Constellation of the 1950s

★ The De Havilland Comet - the first jet airliner in service

★ The Sud Caravelle - the first successful jet airliner.

★ The Boeing 707 and Douglas DC-8 - The American-built jetliners

★ The Boeing 727 - one of the most successful airliners

★ The Douglas DC-10 and Lockheed L-1011 TriStar - one of the first wide-bodies

★ The Douglas DC-9 - more than 1000 built. Many still in service.

★ The Boeing 737 - the best selling civilian jet airliner

★ The Airbus A300- of fly-by-wire

★ The Concorde - flew at twice the speed of sound and operated from 1976 to 2003 by British Airways and Air France

★ The Airbus A330/Airbus A340

★ The Boeing 747 "jumbo jet" - the largest airliner between 1968 and 2005

★ The Boeing 777 - the first airliner designed entirely by computer (no mockups were used)

★ The Airbus A380 "superjumbo" - The world's largest airliner, featuring two full-length twin-aisle passenger cabins, is expected to start service with Singapore Airlines in October 2007.

Airliner recycling

As airliners are very expensive, most are leased out for times typically from 20 to 40 years. Very few go back into service after a long lease is up because evolving aerospace technology leaves older airliners unable to compete against newer machines that can be operated at a lower cost. Many end-of-service airliners end up in the Mojave Desert, at the Mojave Spaceport (also known as "The Airplane Boneyard"). From this, the term "Mojave" has come to refer to the temporary storage of aircraft, e.g. during decreased demand for air travel and between short-term leases. Another common location to retire airliners is Marana, Arizona.
While eventually almost every airliner will be reduced to scrap (the exceptions end up as museum pieces or flown by collector groups) they may pass through many owners before they are retired. A well-maintained airliner can operate safely for decades, depending on how often it is flown, its operating environment, and whether damage and wear and tear is properly repaired.
What may end an airliner's working life is a lack of spare parts, as the original manufacturer and third manufacturers may no longer provide or support them. Corrosion and metal fatigue are other issues that become more expensive to deal with as time goes on. Eventually, these factors and advances in aircraft technology lead to older airliners becoming too expensive or inefficient to operate.
In order to protect the environment, the Airbus company has set up a special centre in France to decommission and recycle older aircraft. More than 200 airliners will finish active life each year, and will be dismantled and recycled under the newly established PAMELA Project.

Cabin configurations

An airliner may have several classes of seating: first class, business class, and/or economy class (which may be referred to as coach class or tourist class, and sometimes has a separate "premium" economy section with more legroom and amenities). The seats in more expensive classes are wider, more comfortable, and have more amenities such as "lie flat" seats for more comfortable sleeping on long flights. Generally, the more expensive the class, the better the beverage and meal service.
Domestic flights generally have a two-class configuration, usually first or business class and coach class, although many airlines instead offer all-economy seating. International flights generally have either a two-class configuration or a three-class configuration, depending on the airline, route and aircraft type. Many airliners offer movies or audio/video on demand (this is standard in first and business class on many international flights and may be available on economy). Cabins of any class are provided with lavatory facilities (see board toilets).
Main articles: aircraft cabin

Seats

Main articles: Airline seat

The types of seats that are provided and how much legroom is given to each passenger are decisions made by the individual airlines, not the aircraft manufacturers. Seats are mounted in "tracks" on the floor of the cabin and can be moved back and forth by the maintenance staff or removed altogether. Naturally the airline tries to maximize the number of seats available in every aircraft to carry the largest possible (and therefore most profitable) number of passengers.
Passengers seated in an 'exit row' (the row of seats adjacent to an emergency exit) usually enjoy substantially more legroom than those seated in the remainder of the cabin, while the seats directly in front of the exit row may have less legroom and may not even recline (for evacuation safety reasons). However, passengers seated in an exit row may be required to assist cabin crew during an emergency evacuation of the aircraft opening the emergency exit and assisting fellow passengers to the exit. As a precaution, many airlines prohibit young people under the age of 15 from being seated in the exit row [1].
The seats are designed to withstand strong forces so as not to break or come loose from their floor tracks during turbulence or accidents. The backs of seats are often equipped with a fold-down tray for eating, writing, or as a place to set up a portable computer, or a music or video player. Seats without another row of seats in front of them have a tray that is either folded into the armrest or that clips into brackets on the underside of the armrests. However, seats in premium cabins generally have trays in the armrests or clip-on trays, regardless of whether there is another row of seats in front of them. Seatbacks now often feature small color LCD screens for videos, television and video games. Controls for this display as well as an outlet to plug in audio headsets are normally found in the armrest of each seat.

Overhead bins

The overhead bins are used for stowing carry-on baggage and other items. While the airliner manufacturer will normally supply a standard product, airlines may choose to have bins of differing size, shape, or color installed. Over time, these bins evolved out of what were originally overhead shelves used for little more than coat and briefcase storage. As concerns about falling debris during turbulence or in accidents increased, enclosed bins became the norm. Bins have increased in size in order to accommodate the larger carry-on baggage passengers may bring onto the aircraft. New bin designs may include a handrail, useful when moving through the cabin.

Passenger service units

Above the passenger seats are Passenger Service Units (PSU). These typically contain a reading light, air vent, and a flight attendant call button. The units frequently have small "Fasten Seat Belt" and "No Smoking" illuminated signage and may also contain a speaker for the cabin public address system.
The PSU will also normally contain the drop-down oxygen masks which are activated if there is a sudden drop in cabin pressure. These are supplied with oxygen by means of a chemical oxygen generator. By using a chemical reaction rather than a connection to an oxygen tank, these devices supply breathing oxygen for long enough for the airliner to descend to thicker, more breathable air. Oxygen generators do generate considerable heat in the process. Because of this, the oxygen generators are thermally shielded and are only allowed in commercial airliners when properly installed - they are not permitted to be loaded as freight on passenger-carrying flights. ValuJet Flight 592 crashed on May 11, 1996 as a result of improperly loaded chemical oxygen generators.

Baggage holds

Airliners must have space on board to store baggage that will not safely fit in the passenger cabin. Designed to hold baggage as well as freight, these compartments are called "cargo bins", "holds", or occasionally "pits". These compartments can be accessed through doors on the outside of the aircraft. Despite what is seen in many movies, access doors between passenger cabins and baggage holds are rare in current modern airliners.
Depending on the aircraft, baggage holds are normally pressurized just like the passenger cabin although they may not be heated. While lighting is normally installed for use by the loading crew, typically the compartment is unlit when the door is closed.
Baggage holds on modern airliners are equipped with fire detection equipment and larger aircraft have automated or remotely activated fire-fighting devices installed.

Narrow-body airliners

Most "narrow-body" airliners with more than 100 seats have space below the cabin floor, while smaller aircraft often have a special compartment separate from the passenger area but on the same level.
Baggage is normally stacked within the bin by hand, sorted by destination category. Netting that fits across the width of the bin is secured to limit movement of the bags. Airliners often carry items of freight and mail. These may be loaded separately from the baggage or mixed in if they are bound for the same destination. For securing bulky items "hold down" rings are provided to tie items into place.

Wide-body airliners

"Wide-body", or "jumbo jets", frequently have a compartment like the ones described above, typically called a "bulk bin". It is normally used for late arriving luggage or bags which may have been checked at the gate.
However, most baggage and loose freight items are loaded into containers called Unit Load Devices (ULDs), often referred to as "cans". ULDs come in a variety of sizes and shapes, but the most common model is the LD-3. This particular container has approximately the same height as the cargo compartment and fits across half of its width.
ULDs are loaded with baggage and are transported to the aircraft on dolly carts and loaded into the baggage hold by a loader designed for the task. By means of belts, rollers and drive wheels, an operator can maneuver the ULD from the dolly cart, up to the aircraft baggage hold door, and into the aircraft. Inside the hold, the floor is also equipped with drive wheels and rollers that an operator inside can use to move the ULD properly into place. Locks in the floor are used to hold the ULD in place during flight.
For consolidated freight loads, like a pallet of boxes or an item too oddly shaped to fit into a container, flat metal pallets that resemble large baking sheets that are compatible with the loading equipment are used.

See also

★ Airport

★ Flight planning

★ List of civil aircraft

★ Plane spotting

★ Air safety

★ List of airliners by Maximum Take-Off Weight

External links and references

★ Boeing

★ Airbus (EADS)

★ Embraer

★ Bombardier

★ ATR

★ Canadian Air Transport Security Authority (CATSA) official website

★ Airliners.net