The genealogy of the A380 is a contorted maze of unusual relationships, deadends and improbable possibilities.
The roots of Europe's largest ever civil aircraft programme reach back to the late 1980s, when Airbus began studies of 600 to 800-seat airliners to serve what it believed would be an increasingly congested global air transport market in the early decades of the 21st century.
The A380 is a direct descendant of the A3XX, which led from the formation of the A3XX Integrated Team in October 1993. This effectively took over earlier Ultra High Capacity Aircraft (UHCA) studies, which were the consortium's first serious evaluations of an aircraft to replace Boeing's dominant 747.
By 1991, Airbus had begun initial talks with several major carriers on potential requirements for a family of UHCAs. Driven largely by the Asia-based airlines, all the concepts were significantly larger than the 747, and consisted of a series of 600, 800 and 1,000-seater designs. Airbus considered many options to create these behemoths including joining two A340 fuselages laterally, as well as a variety of highly unconventional ovoid, horizontal double-bubble, circular and even clover leaf cross-sections. In conjunction with a Russian technical institute it also studied a massive tail-less flying wing concept.
Besides its own UHCA studies, Airbus asked the partner companies to look at their own large aircraft concepts. Throughout 1991 and 1992, Aerospatiale worked on the ASX 500/600, Daimler-Benz Aerospace (DASA) Airbus studied the P502/P602 (also dubbed A2000) and British Aerospace evaluated the AC14. The results of all three concepts were to feed directly into what became the A3XX.
Events then took a dramatic and unexpected turn. Asian airlines, as well as some ambitious transpacific carriers such as United Airlines, began encouraging Boeing to look at a larger aircraft than the 747. In January 1993 Boeing took the industry by surprise when it issued statements with the four Airbus consortium members announcing a year-long study to examine the feasibility of developing a Very Large Commercial Transport (VLCT). The agreements were exclusively between Boeing, Aerospatiale, BAe, CASA and DASA and not with Airbus itself. The VLCT study was to examine the market potential for a large aircraft capable of carrying between 550 and 800 passengers over ranges of 13,000 to 18,500km (7,000 to 10,000nm).
Led by Boeing's John Hayhurst and Jrgen Thomas of DASA, the VLCT study was viewed with suspicion by most at Airbus. Hayhurst stated that the group was established because "we currently believe that such a project would be too big for any one manufacturer". However, Airbus saw it as a clever gambit to delay the UHCA and create a wedge between Airbus and its European partners.
Ironically, the creation of the VLCT was to have exactly the opposite effect, and led directly to the birth of the A3XX. In response to the Boeing initiative, Airbus redirected its UHCA study towards a "smaller" large aircraft with 400 to 600 seats - lees than the VLCT study area and closer to the 747 replacement and growth market identified before.
In June 1993 the three original large aircraft proposals from the Airbus partners were grouped together for the first time. The designs took elements of the ASX, P502 and AC14 models and created a "Family 1" design based on a double-deck layout.
In October, Airbus created the A3XX Integrated Team, tasked with deciding between two baseline 500-600-seat options. One was the UHCA-based A3XX-H600, the double A340 fuselage concept studied earlier. The other was the A3XX-V600, a 'vertical ovoid' cross-section based on the "Family 1" concept.
In January 1994 the team dropped the A3XX-H600 in favour of the double-deck design. Many factors contributed to the decision, one of the largest being the cabin evacuation problems associated with the14-abreast layout of the twin hulls. The -V600 offered more flexibility with a 10-abreast main deck and a seven-abreast upper deck.
Meanwhile, the VLCT rumbled on and, in March 1994, Airbus was formally accepted into the study. By this time definition of the A3XX was starting to rapidly evolve, the fledgling design having already achieved "Status Five" (or fifth major iteration) by April 1994. The rate of iteration change subsequently slowed, with the final pre-launch benchmark being "Status 15" in 2000. Major changes made in 1994 included the adoption of four rather than three main landing gear legs, moving the wings further aft, a two-frame stretch of the baseline model and a target capacity of between 530 and 630 passengers.
By June 1995 VLCT studies were winding down after two-and-a-half years, the joint effort being abandoned after the group's findings that "market studies do not indicate sufficient volumes to justify the launch of the programme at the moment". Around this time Airbus reached Status 6C on the A3XX and changed the cross-section to offer up to eight abreast on the upper deck. Status 7, configured four months after the abandonment of the joint US-European study, evaluated the A3XX against the VLCT study aircraft.
The next year saw the formation of the Airbus Large Aircraft Division, and some more changes to the A3XX in response to airline input. "We decided to put everything under one roof - engines, systems and so on, to prepare for the A380," says Robert Lafontan, A380 senior vice-president engineering. "By then we had frozen almost everything. The concept was basically as it is today."
Major changes made in Status 6 that year included the key decision to seek new engines rather than go for derivatives. This was partially driven by rising payload and range demands, and the associated decision to raise the wing area from 725m2 to 780m2. A main driver for the change was Singapore Airlines. "Our customer wanted to be able to fly with 555 passengers and cargo from Singapore to London - or around 1,400km. Why 555? Well we did a market survey and we saw we needed at least 30% more capacity than a 747, and that confirmed it," says Lafontan.
Changes introduced in 1997 included a revised frame pitch and the relocation of the engines further outboard. This reflected the growing size of the powerplants, the larger area of the wing and the need for additional wing bending moment relief, as well as protection of systems and structure from rotor burst.
Status 10a in early 1998 saw a further increase in wing size to 817m2, revisions to the main gear and an improved low-drag rear fuselage. A world tour of an upper deck mock-up also prompted further cross-section improvements. It was also decided to study reduced natural stability to allow a 5% reduction in the 200m2 horizontal tailplane area and a -50 short-bodied version, now dubbed the -700, was added to the family.
1998 saw improvements to nose aerodynamics and empennage, refinements of the wing structure and position, changes to the belly fairing and the addition of A320-style wingtip fences. By late 1999 the flap track fairings had been changed, and the wing dihedral angle slightly reduced. The year also saw confirmation of the extensive use of Glare, lightweight alloys and other advanced lighterweight materials.
Before commercial launch was finally achieved on 23 June 2000, Airbus had one more major round of changes to make to the A380 - all of them driven by the relatively late emergence of London's stiff QC2 noise regulations. The changes were vital as they would particularly impact the late night departure and early morning arrivals of its largely Asia-based customers.
To improve the aircraft's lift/drag ratio by 5%, particularly for improved take-off and climb out, the high-lift systems were modified with aileron droop for take-off along with a reduced setting. A drooped nose device was also introduced for the inboard leading edge to improve take-off. The variable position leading edge droop device was used in lieu of a Kruger flap that was not feasible with the deep root and three-dimensional curvature of the A380 wing (see Section B).
Engine fan diameter was also enlarged, along with other propulsion system enhancements, while the flight management system was optimised for improved take-off and noise abatement procedures. With all major design changes now behind it, the design team completed detailed definition in mid-2002 and is expected to reach the 90-95% detailed design release point by September 2003.
Source: Flight International
