Manufacturers A380 faces wing-cracking problems

Four years after entry into service, the Airbus A380 – the world’s largest airliner –

20th Jan 2012


 Manufacturers

A380 faces wing-cracking problems
 

 Still recovering from the consequences of an uncontained engine failure on a Qantas aircraft in November 2010, the Airbus A380 programme now faces an issue with wing cracking, writes Andrzej Jeziorski.

Four years after entry into service, the Airbus A380 – the world’s largest airliner – is facing a wave of negative press after reports of cracks found in the wings of aircraft operated by Qantas and Singapore Airlines (SIA).
The airlines first stated publicly on 6 January that cracks had been found in the wing ribs of a “limited number” of the double-deck quad-jets, although they added that the discovery did not affect the safety of the aircraft.
SIA said the cracks had been discovered in “a small number of wing-rib feet” on two aircraft and repairs had been carried out. The airline said it would continue to carry out inspections and any necessary repairs on other aircraft as they come up for routine inspection.
Separately, Australia’s Qantas said it had found “miniscule cracking” in the wing ribs of one A380 undergoing repairs in Singapore after it suffered an uncontained failure of one of its Rolls-Royce Trent 900 engines in November 2010. The cracks were unrelated to the engine incident, Qantas said, adding that they had been repaired.
 

 ‘No immediate action’
According to the Australian airline: “No immediate action is required by A380 operators because the cracking presents no risk whatsoever to flight safety.” Qantas said Airbus was developing formal guidance that would probably require A380 operators to inspect wing ribs for this type of cracking every four years.
Airbus head of engineering Charles Champion told reporters that the manufacturer’s analysis showed the cracks – less than a centimetre long – posed no threat to aircraft safety. The company had been informing authorities including the European Aviation Safety Agency (EASA) about the issue, but there were no plans to release airworthiness directives requiring any special action by airlines.
The engineers’ trade union Australian Licensed Aircraft Engineers Association (ALAEA) was sceptical, with the union’s Federal President Paul Cousins telling the Sydney Morning Herald that “a Band-Aid fix has been applied to a situation that could become very serious”.
“Our concern is a continuing stress on the wing,” Cousins told the paper. “In this case, Airbus and the European Aviation Safety Agency have been too quick to come out with a fix, rather than saying we need to investigate further.”
Airbus has now traced the origin of the cracks back to unexpected stresses arising during the manufacturing process. The company said it remained confident in its original flight-loading calculations.
As Asian Aviation went to press, Airbus was in the process of changing the manufacturing process and EASA was expected to tell operators to carry out precautionary inspections. The manufacturer insisted that the cracks do not represent a threat to safety in the short to medium term.
The A380’s wings are manufactured at Airbus’s Broughton plant in the UK and then transferred to the company’s assembly line in Toulouse, France. Press reports say that investigations have shown the cracked parts were being placed under stress at some point during manufacture, as the wing skin is placed over the framework of wing ribs and spars before being attached, creating standing stresses in the assembled structure.
Airbus insisted that the cracks would have shown up in routine heavy maintenance of the aircraft, even though they were initially discovered as a consequence of the November 2010 engine failure incident on Qantas flight QF32.
 

Legal options
About a month before the discovery of the wing cracks, Qantas said it had begun discussions with engine manufacturer Rolls-Royce “on a range of issues concerning the A380 fleet, including financial and operational impacts, as a consequence of the QF32 Trent 900 engine failure ... and will also consider legal options”.
On 2 December, Qantas filed a statement of claim and was granted an injunction by the Federal Court of Australia, ensuring that the company can pursue legal action against the engine maker in Australia “if a commercial settlement is not possible”.
The move “allows Qantas to keep all options available to the company to recover losses, as a result of the grounding of the A380 fleet and the operational constraints currently imposed on A380 services”.
Trent 900 engines on the global A380 fleet remain subject to an EASA directive issued on 10 November, mandating that all the engines should be inspected every 20 flight cycles.
“Qantas will fully comply with this directive – both for A380s brought back into service and for new aircraft entering the Qantas fleet,” the airline said.
 

 

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