Small cracks found on a few A380's

The discovery of tiny cracks in one of the wings of a Qantas A380 under extensive repair in Singapore has led to the detection of similar problems in four other Airbus superjumbos worldwide.

The cracks - less than a centimetre long - in the wing ribs of the A380s do not pose an immediate threat to the safety of the aircraft. The ribs are vertical fixtures that stabilise the wings.

But their detection is expected to prompt Airbus to issue a service bulletin to airlines later this month requiring them to check for the problem when their A380s are due for heavy maintenance every four years.

Engineers only discovered the cracks in the wing ribs of the Qantas A380 - named the Nancy Bird-Walton - while they were conducting $130 million in repair work on the aircraft at Changi Airport.

Their initial suspicion was that the cracks - with a width hardly visible to the naked eye - were caused by the A380's mid-air engine explosion shortly after take off from Singapore in November 2010.

But subsequent investigations have found this was not the case and engineers have discovered similar cracks on three Airbus test aircraft and one operated by Singapore Airlines.

The cause of the cracks in the Nancy Bird-Walton's wing is still to be determined but an initial assessment is believed to pin the blame more on the way the wing ribs were constructed rather than due to the loads and thrust at which the aircraft was operated by Qantas.

The Nancy Bird-Walton had only been in service for two years when the engine exploded.

Qantas confirmed yesterday that ''minuscule cracking'' was found in the wing ribs of the Nancy Bird-Walton but it was ''not unique to Qantas''.

''No immediate action is required by A380 operators because the cracking presents no risk whatsoever to flight safety,'' a spokesman said.

''Formal guidance is being developed by Airbus that is likely to require A380 operators to inspect wing ribs for this type of cracking every four years - in line with scheduled maintenance checks. Qantas will comply fully with this guidance when it is published.''

Singapore Airlines confirmed yesterday a ''small number of cracks'' had been found on the wing rib feet of one of its A380s during an investigation in the second half of last year.

The cracks in the Qantas A380 have since been fixed, but other repair work to get the aircraft back into service is not expected to be finished until March.

Qantas has a further 11 superjumbos in its fleet which fly long-haul international routes to London and Los Angeles.

It will take delivery of two A380s next year but has deferred orders for a further six superjumbos by up to six years. Airbus declined to comment yesterday.

(Matt O'Sullivan - The Sydney Morning Herald)