The wing of the Airbus A380 static test specimen suffered a
structural failure below the ultimate load target during trials in
Toulouse earlier this week, but Airbus is confident that it will
not need to modify production aircraft.
The airframer has been running load trials on a full scale A380
static test specimen in Toulouse since late 2004 (pictured below).
After completing limit load tests (ie the maximum loads likely to
experienced by the aircraft during normal service), progressively
greater loads have been applied to the specimen towards the
required 1.5 times the limit load. Engineers develop finite element
models (FEM) to calculate the load requirements.
The failure occurred last Tuesday between 1.45 and 1.5 times the
limit load at a point between the inboard and outboard engines,
says Airbus executive vice president engineering Alain Garcia.
This is within 3% of the 1.5 target, which shows the accuracy of
the FEM. He adds that the ultimate load trial is an extremely
severe test during which a wing deflection of 7.4m (24.3ft) was
recorded.
The European Aviation Safety Agency (EASA) says that the maximum
loading conditions are defined in the A380 certification basis.
The aircraft structure is analysed and tested to demonstrate that
the structure can withstand the maximum loads, including a factor
of safety of 1.5. This process is ongoing and will be completed
before type certification.
However Garcia says that the failure of the wing below the 1.5
target will require essentially no modifications to production
aircraft: This static test airframe has the first set of wings
built, and we have refined the structural design for subsequent
aircraft due to increased weights etc. We will use this calibration
of the FEM to prove the adequacy of the structure on production
aircraft.
EASA says that it is aware of the structural failure but "cannot
make a statement about the specific failure as it has not been
officially briefed by Airbus on what the cause was, and the
certification process is ongoing".
Garcia says that the FEM calculations had already established that
the A380s wing had no margin at ultimate load. We had a weight
saving programme and played the game to achieve ultimate load.
However in earlier briefings, Airbus structural engineers had
stated that it planned to carry out a residual strength and margin
research test in 2006 after completing ultimate load trials.
The results gleaned from the static testing will be extrapolated
for the future aircraft developments over the next 40 to 50 years
says Garcia. It is normal to refine and strengthen the structure
of new heavier or longer range variants, he says.
http://www.flightglobal.com/Articles/2006/02/17/Navigation/177/204716/Airbus+A380+test+wing+breaks+just+below+ultimate+load.html
And that Plane, I think will be operational soon... even prep for
Aero-space Exhibition. And It flew here 
