PARIS Airbus acknowledged a combination of manufacturing and design flaws on Wednesday as it confirmed the discovery of more examples of cracks inside the wings of A380 superjumbo jets, while insisting the world's largest airliner is safe to fly.
A top executive said the European planemaker had found a solution to the outbreak of cracks on a small number of parts inside the wings, which prompted European safety authorities to order compulsory safety inspections last week.
Airbus confirmed a Reuters report that it had discovered more examples of the cracks during the latest wing inspections, but declined to give further details before Friday's deadilne for completing a first phase of checks.
"The A380 is safe to fly," Tom Williams, executive vice president of programmes at Airbus, said.
The cracks were caused by a combination of the choice of aluminium alloy for certain wing brackets as well as stresses imposed at two stages of the manufacturing process, he said.
Airbus moved to shore up confidence in the world's largest jetliner amid a drip-feed of disclosures about cracking on components used to fix the outside of the wing to its ribcage.
Williams flew to Dublin to give an unscheduled address at a conference followed by a series of briefings as Airbus stepped up efforts to dampen any concerns about the aircraft's safety.
Airbus had already dismissed calls by an Australian engineering union to ground the aircraft, saying this had not been demanded by safety regulators who would be only too quick to ban flights if they believed safety was at risk.
European authorities have however ordered inspections on almost a third of the superjumbo fleet after two types of cracks were discovered within weeks of each of other on what Airbus described as handful of L-shaped brackets inside the wing.
Since then, similar cracks have been found inside the 9,100-square-foot wings of at least one of the superjumbos examined under the directive, industry sources told Reuters on Tuesday.
Airbus officials said it was assumed that most of the aircraft being tested would show evidence of the second and more significant type of crack, but that their technical fixes would address this well before they became a potential hazard.
It declined to say which airline had found cracks during inspections but the spotlight is expected to fall on Singapore Airlines which has said it is inspecting six aircraft under a first phase of checks of the most heavily used jets.
Singapore Airlines said it was carrying out inspections as required and would give an update once they were completed. The checks involve emptying and venting fuel checks for about 24 hours followed by a visual check via a manhole under the wing.
(Reporting by Tim Hepher, Editing by Elaine Hardcastle)