A380 Retrofit: A Painful Learning Process
By Robert Wall, Jens Flottau
Source: Aviation Week & Space Technology
May 28, 2012
Robert Wall and Jens Flottau/Toulouse
If there is an upside to the A380's wing-component cracking saga, it may be that it should enable Airbus to avoid an embarrassing misstep on its next big development program, the A350.
Airbus has scrutinized the design process for the twin-widebody in light of lessons learned in determining why wing rib feet in the A380 were failing. It has upgraded its finite-element models and removed from the A350 potentially dubious parts, made of a particular aluminum alloy, replacing them with ones made of aluminum lithium that should be less susceptible to cracking.
For the first time, Airbus will also have an aircraft-wide finite-element model run before the static test article is worked on. Those models have been refined to close the gaps seen in the A380 work, drawing in part on the greater processing power that is available now but was not in hand when the A380 wing design work was first undertaken.
However, those long-term advantages are overshadowed by the difficulties encountered in identifying the problem's cause and having to retrofit 120 A380s to fix the problem. The retrofit must be applied to the 74 A380s already delivered as well as to another approximately 46 in the production system now.
Airbus has developed two approaches it believes will permanently deal with the cracking of some rib feet, says Tom Williams, executive vice president for programs. The problem has led to an airworthiness directive from the European Aviation Safety Agency (EASA) requiring enhanced inspection intervals and fixes where component cracking is found.
One approach addresses the retrofit repair and the other focuses on altering the production process to avert the problem. The fixes should restore the aircraft life to 19,000 flight cycles and bring inspection intervals back to normal, Williams says.
Airbus expects repair expenses to top €260 million ($327 million) this year. “It has cost the company dearly,” acknowledges Airbus CEO Tom Enders, referring to both the finances and reputation of aircraft maker. It also highlights the risk of trying to innovate, because some of the material choices were made with good intentions but without fully understanding the risks involved.