The head of Airbus said he ordered an internal investigation into how the company allowed wing cracks to develop on its flagship A380 passenger jet, acting to draw a line under weeks of embarrassing publicity for the world's largest planemaker.

Chief Executive Tom Enders reiterated that the world's largest jetliner was safe to fly as engineers repair hairline cracks in the wings, and he sought to allay any concerns the setback to Europe's industrial prestige could spread to the future A350.

"We made a little mistake here and we are repairing it as quickly as possible," Enders told a news conference at the Singapore Airshow on Wednesday. "This plane is absolutely safe to fly."

"Are we learning from this? Absolutely. We are taking lessons from the A380 programme for the A350 programme," he said, referring to the company's next project, a mid-sized jetliner designed to compete with the Boeing 787 Dreamliner.

"We have a thorough investigation underway on how we could make these mistakes in the first place and to eradicate the sources of the mistakes," he added.

A drip-feed of disclosures about the cracks, which Airbus and regulators say do not affect parts critical to safety for the time being, has left Airbus red-faced and overshadowed Enders' appointment to run parent EADS from June.

After initially underestimating public concern about teething problems on the double-decker plane, Airbus has progressively laid out detailed information on the parts involved and errors in its UK manufacturing plants.

Airbus has said a combination of design and manufacturing slips put too much stress on a handful of the 2,000 brackets that fix the exterior of each wing to the ribcage beneath, but Enders' comments indicate he intends to dig deeper.

The German-born reserve paratrooper has a reputation for straight-shooting and people close to the company say he is unlikely to want to allow the episode to haunt his transition to the top role at EADS or spoil the legacy to his successor, current number two, Fabrice Bregier.

As head of Airbus since 2007, Enders led the turnaround of the troubled A400M military transport project, leading to a bailout worth billions of euros by seven European nations, but far less support is likely if major civilian projects founder. Airbus employs some 55,000 people.

European air safety officials extended checks for Airbus A380 wing cracks to the entire superjumbo fleet earlier this month after engineers concluded the problems were structural and widespread.

Enders declined to comment on a German media report that the slip-up could cost Airbus EUR100 million (83.7 million pounds) to fix, but acknowledged it was likely to be "a bit of money."

Airbus officials say the cracks affect an average of five out of 2,000 aluminium alloy brackets known as rib feet per wing. Each must be replaced, meaning about 10 per aircraft or 690 for the 69 aircraft now in service have to be refitted.

The process involves taking the giant 525-seat plane out of service for several days, for which Airbus is expected to have to compensate airline customers.

A senior industry official said the cost was likely to be secondary. "Airbus will get this right. It's not about money. It's about credibility and confidence."

Boeing Also Hit

The Singapore Airshow is Asia's largest aviation and arms exhibition and is held every two years. It has been buzzing with talk about mishaps at the world's dominant planemakers as they pull out all the stops to promote their latest products.

Boeing said this month it found a process called "delamination" on part of the rear fuselage of its carbon-composite 787 Dreamliner, a red flag somewhat akin to the cracking on a metal structure, but harder to detect.

Boeing has said it is carrying out inspections and has worked out how to fix the aircraft waiting to be delivered.

Mark Jenks, vice president of 787-9 development at Boeing Commercial Airplanes, said its customers understood the problem was "straightforward". "It's more of a big issue in press conferences," he told Reuters.

The Dreamliner problems will provide little relief to Airbus as its A350 is also being built of carbon materials.

Modern carbon-fibre aircraft are lighter, which saves fuel. The manufacturers use technology that allows them to weave together strong structures made of carbon fibre. The technology has been in use for some aircraft parts and military airframes for years, but Boeing's 787 is a first for a large passenger plane's fuselage.

Fuel is by far the biggest cost for low-cost airlines which have been powering the rapid growth of Asian aviation. Boeing basked in confirmation of a record order for 230 planes from Indonesian low-cost carrier Lion Air in a deal worth US$22.4 billion (14.2 billion pounds) at list prices.

Airbus, meanwhile, moved to meet criticism from airlines over its freight strategy by unveiling a deal with Singapore-based ST Aerospace to convert A330 passenger jets into cargo planes, giving them a second lease of life to tap into expanding trade with countries such as China.

China and other Asia-Pacific nations will take delivery of 9,370 passenger jets over the next 20 years, valued at US$1.3 trillion (826.3 billion pounds), helping to power the aerospace industry's growth, Airbus said on Wednesday.

Sales chief John Leahy said the rapid urbanization of Asia's population and sharp growth in emerging economies compared with the industrialized nations would soon make Asia the busiest market for air travel, displacing the United States.