Australian aircraft engineers say all Airbus A380s -- the world's largest passenger aircraft -- must be grounded after both Singapore Airlines and Qantas found cracks in the wings of their super-jumbos.

The Australian Licensed Aircraft Engineers Association (ALAEA) sounded the alarm this week on one of the world's most iconic passenger aircraft designs, arguing that it suffers from a design flaw.

We can't continue to gamble with people's lives and allow those aircraft to fly around and hope that they make it until their four-yearly inspection, said Steve Purvinas, secretary of the ALAEA.

Qantas, Singapore Airlines, and Airbus admitted they had discovered cracks, but maintained that the aircraft were safe.

The cracks in brackets inside the wings do not pose a safety risk, the plane builder said Monday. According to Airbus, the hairline cracks are on a small L-shaped bracket inside the wing. The company reiterated that the European aviation safety authority supported their decision to deal with the cracks during the aircrafts' routine maintenance every four years.

The four-engine aircraft, manufactured by Airbus (a subsidiary of the European Aeronautic Defense and Space Company), saw its maiden flight in April 2005 and was introduced into the commercial market in October 2007. By far the largest passenger jet in the skies, it offers nearly 50 percent more floor space than rival Boeing Company's BA 747-400.

In total, 67 Airbus A380s are in use across the globe on seven airlines: Emirates, Air France, Lufthansa, Korean Airlines, China Southern, Qantas and Singapore Airlines.

The planes hold 525 passengers in a typical three-class arrangement. Currently, Singapore Airlines operates 14 while Qantas operates 10. 238 aircraft have been ordered by 17 airlines worldwide.

The cracking problems comes at a bad time for Airbus as it tries to sell new customers on the aircraft and ward off Boeing, which recently unveiled the Boeing 747-8 Intercontinental. The 747-8 took its maiden flight in February 2010.