page_title: Airbus A340
section_title: Design
hierarchical_section_title: Airbus A340 / Design
caption_attribution_description: English: An Airbus 340-600 photographed above Toulouse during a test flight in 2007. The aircraft is seen in clean-wing configuration (with flaps and slats fully retracted).
context_page_description: The Airbus A340 is a long-range, wide-body commercial passenger jet airliner that was developed and produced by the European aerospace company Airbus.
  In the mid-1970s, Airbus conceived several derivatives of the A300, its first airliner, and developed the A340 quadjet in parallel with the A330 twinjet.
  In June 1987, Airbus launched both designs with their first orders and the A340-300 took its maiden flight on 25 October 1991.
  It was certified along with the A340-200 on 22 December 1992 and both versions entered service in March 1993 with launch customers Lufthansa and Air France.
  The larger A340-500/600 were launched on 8 December 1997, the A340-600 flew for the first time on 23 April 2001 and entered service on 1 August 2002.
  Keeping the eight-abreast economy cross-section of the A300, the early A340-200/300 has a similar airframe to the A330.
  Differences include four 151 kN CFM56s instead of two high-thrust turbofans to bypass ETOPS restrictions on trans-oceanic routes, and a three-leg main landing gear instead of two for a heavier 276 t MTOW.
  Both airliners have fly-by-wire controls, which was first introduced on the A320, as well as a similar glass cockpit.
context_section_description: The Airbus A340 is a twin-aisle passenger airliner, the first long-range Airbus, powered by four turbofan jet engines. It was developed upon earlier Airbus aircraft and their features like the A320 glass cockpit; it shares many components with the A330, notably identical fly-by-wire control systems and similar wings. Its features and improvements were usually shared with the A330. The four engines configuration avoided the ETOPS constraints such as more frequent inspections.
  The A340 has a low cantilever wing; the A340-200/300 wing is virtually identical to that of the A330, with both engine pylons used while only the inboard one is used on the A330. The two engines for each wing provide a more distributed weight; and a more outboard engine weight for a lower wing root bending moment at equal TOW, allowing a higher wing limited MTOW for more range. The wings were designed and manufactured by BAe, which developed a long slender wing with a high aspect ratio for a higher aerodynamic efficiency.
  The wing is swept back at 30 degrees, allowing a maximum operating Mach number of 0.86. To reach a long span and high aspect ratio without a large weight penalty, the wing has relatively high Thickness-to-chord ratio of 11.8% or 12.8%. Jet airliners have Thickness-to-chord ratios ranging from 9.4% (MD-11 or Boeing 747) to 13% (Avro RJ or 737 Classic). Each wing also has a 2.74 m (9.0 ft) tall winglet instead of the wingtip fences found on earlier Airbus aircraft. The failure of the ultra-high-bypass IAE SuperFan, promising around 15% better fuel burn, led to wing upgrades to compensate. Originally designed with a 56 m (184 ft) span, the wing was later extended to 58.6 m (192 ft) and finally to 60.3 m (198 ft). This wingspan is similar to that of the larger Boeing 747-200, but with 35% less wing area.
  The A340 uses a modified A320 glass cockpit, with side-stick controls instead of a conventional yoke. The main instrument panel is dominated by six displays, cathode ray tube monitors initially then liquid crystal displays. Flight information is directed via the Electronic Flight Instrument System (EFIS) and systems information through the Electronic Centralised Aircraft Monitor (ECAM).
  The aircraft monitors various sensors and automatically alerts the crew to any parameters outside of their normal range; pilots can also inspect individual systems. Electronic manuals are used instead of paper ones, with optional web-based updates. Maintenance difficulty and cost were reduced to half of that of the earlier and smaller Airbus A310. Improved engine control and monitoring improved time on wing. The centralised maintenance computer can transmit real-time information to ground facilities via the onboard satellite-based ACARS datalink. Heavy maintenance like structural changes remained unchanged, while cabin sophistications, like the in-flight entertainment, were increased over preceding airliners.
caption: The 9.2 aspect ratio and 31° sweep of the A340-600 wing
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