Home' Asian Aviation : AAV July August 2010 Contents 32 AsianAviation | JULY--AUGUST 2010
body", which boasts a ten-abreast capacity for back-
packing economy travellers, as well as a seven-abreast
"regional business" capacity. Just one of the factors in
Emirates Airline's selection of the Boeing 777 over
the A330 in competing markets was the former's
wider cabin that provided lower seat-mile costs.
A350-800 and -900 models offer a high level
of structural and systems commonality, sharing a
for ward fuselage, rear fuselage and empennage, outer-
and centre-wing box, wing leading and trailing edges
and related high-li devices, and engine struts, says
de Zotti. Relative to the larger -900, the A350-800
has modi ed for ward- and a -fuselage sections: these
changes include "re-sizing of [for ward] section 13/14
and [a ] 16/18 and the centre-fuselage upper shell".
Systems common to the two variants are :
undercarriage ; flight controls and hydraulics;
leading- and trailing-edge slat and ap actuators,
sha s, power-control unit, and wingtip "brakes"; air,
auxiliary-power unit, fuel and 'inerting' systems; and
electric-power generation and distribution. Systems
changes on the -800 from the initial A350-900
involve adapted crew-oxygen and re-extinguisher
bottles and ight-control so ware, and six cabin-
ventilation zones -- a reduction of one.
The larger A350-1000 will have higher design
weights and payload, a lengthened body with six
additional fuselage frames ahead of the wing and
ve behind, strengthened airframe and revised wing
trailing edges. Larger, six-wheel landing-gear bogies are
carried in a wheel well extended in length by one frame.
e variant also features engine "bespoke fan module
and core technology" and modi ed air conditioning.
e manufacturer plans to achieve programme
maturity at ser vice entry via structure- and systems-
testing pyramids, covering design; component and
sub-assembly demonstrators; and systems-integration,
full-scale airframe structures, and 'iron bird' systems
testing. A350 customer and business-programme
development vice-president Francois Caudron says
fuselage, pylon, and wingbox demonstrators will
contribute to technology readiness.
Learning from mistakes
Airbus says it has learned from the self-in icted
wounds of the A380 programme, where commonality
between manufactured parts and assembled structures
was compromised and on which buyers were o ered
too much range in cabin customisation.
'De-risking' the manufacturing phase to ensure
a good increase in serial production needed "a lot
of work upfront," says Caudron. Having relied too
much on digital mock-ups (DMUs) with the A380,
Airbus has resorted to a physical mock-up (PMU)
for the new aircra . e A350 DMU and PMU are
"enabling complementary development on complex
areas [and] securing industrialization activities," he
Airbus is currently engaged in a two-year test
"campaign" to prove its design for the A350's carbon-
bre reinforced plastic (CFRP) composite fuselage
construction. An 18m-long, three-section barrel
has been constructed, which de Zotti says "closely
re ects" the nal design. By mid-2010, the limit load
and up to 50 percent-higher ultimate load tests had
been completed successfully.
Computer modelling has been used to identify
key areas of the fuselage for monitoring structural
behaviour under load. For example, the manufacturer
needed to locate any critical areas of likely very local
or more-widespread buckling of skin panels.
Other points considered were the fuselage near
passenger door cut-outs as well as CFRP frame
behaviour, says de Zotti. A refined, non-linear
"global detailed nite element model" is being used to
con rm panel displacement predictions using Aramis
Airbus has constructed a Class 2 cockpit mock-up
using representative equipment to verify the design
of the ight deck and to expedite maturity ahead
of the A350's rst ight in three years' time. Main
considerations in this exercise have been accessibility,
ergonomics, eld of view, illumination, and space
De Zotti says that use of an "Aircraft 1 test
bench" has enabled airlines to validate the new
airliner's cockpit concept and functions, using both
prototype hardware and so ware. Some 300 hours
of development testing has been performed during
17 "campaigns" with Airbus pilots.
No major re-designs
There have been "no major findings requiring
re-design", although de Zotti does not identify
any necessary non-major ndings. Flight-control
architecture has been con rmed and current or future
work involves various validations, including human/
machine interface and human-factors cockpit-
certi cation activities.
By the second quarter of this year, Airbus had
begun construction of the A350 "Aircra 0 'Iron
Bird'" test specimen and various simulators. e
ight-deck owes very much to that of the A380 very-
large airliner, the manufacturer's most recent product,
from which certain changes require validation,
according to de Zotti. For example, the bigger aircra
is able to accommodate much larger screens to display
essentially the same information.
A novelty for Airbus has been to transpose the
location of the on-board information system from the
le -hand side of the cockpit to the central console.
e engineer says this represents a relatively minor
change, but the company is working to ensure that
there are no unintended consequences.
Outside Europe, Airbus has A350 engineering
centres in China and the USA. In Beijing, nearly
200 engineers are engaged on several jobs, including
the rudder and elevators, says Charles Champion,
Airbus's engineering executive vice-president. In
Alabama, Airbus has several cabin-related design
tasks, involving 150 workers. Assignments include
ceiling and sidewall panels, crew-rest compartments,
galleys, lavatories, overhead bins, and passenger seats.
Manufacture of the A350 started late last year with
The A350 XWB flight-deck owes much to that of the A380 very-large airliner.
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