Search for clues in Madrid crash

Accident investigators have begun examining the wreckage of a plane that crashed at Madrid's Barajas airport, leaving 153 passengers dead.

Investigators are still clueless. Right now nobody is suspecting it to be a terrorist attack. Nineteen people have survived the crash and rest are being treated.


See satellite image of airport

Airliner

An airliner is a large fixed-wing aircraft whose primary function is the transportation of 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.

Types of airliners

Wide-body jets

The largest airliners are wide-body jets. In the aviation industry, 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 include the Boeing 747 Jumbo Jet, Boeing 767, Boeing 777, Airbus A300/A310, A330/A340 A350,A380,DC-10, MD-11, and Ilyushin Il-86/96. These aircraft are commonly used for long flights between airline hubs with many passengers.

Narrow-body jets

A smaller, more common class of airliners are the narrow-body or single aisle aircraft. Examples include the Boeing 717, 737, 757, DC-9, MD80 series, and Airbus A320 family. Older airliners like the Boeing 727, DC-8, Fokker 70/100, VC10, Tupolev, and Yakovlev jets also fit into this category. These smaller airliners are generally used for medium distance flights with fewer passengers than the than their wide-body counter-parts.

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 Bombardier CRJ series and "Q" (DASH-8) series, Embraer ERJ 145 family, 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 and thus, depending on local and national regulations, it 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, 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 like the 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.

Airliner variants

Some variants of airliners have been developed for carrying freight or for luxury use 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 C-9), reconnaissance (Embraer ERJ 145, Saab 340, Boeing 737), as well as for troop-carrying roles.

Manufacturers

Historically, a few manufacturers have dominated the market for large airliners. These include:

* American companies

1. Boeing

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

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

* Russian companies (formerly Soviet controlled)

1.Tupolev

2.Ilyushin

3.Antonov (based in Ukraine)

* Europe

1.Airbus Industrie (a multinational conglomeration of smaller European aerospace companies)

* Other major manufacturers include:

1.Embraer (Brazil)

2.Bombardier (Canada,includes the former De Havilland Canada)

3.ATR (France/Italy)

4.Fokker (The Netherlands, now defunct)