Qantas hoses down 'lakes on a plane' fears

By Peter Mitchell and Karlis Salna

Qantas says critical systems on a Melbourne-bound Airbus A380 were never at risk despite the plane and its hundreds of passengers being forced to return to Los Angeles when water flooded the cabin.

Passengers aboard QF94 were forced to spend an extra night in LA after the 15.5-hour flight to Melbourne was aborted an hour after take off, with water flowing from a leaking pipe in business class on the plane's upper deck down the aisle into economy class.

A replacement aircraft was expected to depart LA shortly after 9.30pm Wednesday local time (2.30pm AEST Thursday), with the original aircraft remaining behind with largely cosmetic damage to carpet, seats and other furnishings.

The mid-flight drama prompted some passengers to voice concerns that they had survived a potential calamity, with Hollywood actress Yvette Nicole Brown describing the events as "the scariest thing" she had ever seen.

"It seemed like a problem to me because it is water and electricity," she said.

"All I kept thinking about was, `We are over the Pacific and I'm in something that is full of electricity and there is water'."

After news of the incident broke, Qantas advised that the captain's decision to turn around was not down to a safety issue but a matter of passenger discomfort.

The airline provided further detail on Thursday, confirming that the plane's critical systems were never at risk.

"This is a new generation aircraft and the design standards are the best that aviation has ever seen," Alan Milne, Head of Engineering, Qantas International, told AAP.

"The A380 is built in accordance with those standards and there was absolutely no safety risk as a result of the water leak.

"The critical systems are protected from issues such as water, heat and mechanical damage."

Video and photos taken by passengers show water running down the aisles and seeping from the business class cabin floor down into economy below.

"It look liked a trickle at first and I thought someone had spilt a soda or pop or something and it just got bigger and bigger and it filled up both aisles," Brown told CNN.

"It literally was like a river running down the aisles of the plane.

"It was the scariest thing I have ever seen."

The plane took off from LA International Airport just after midnight on Wednesday and landed back in LA at 2.39am, with passengers put up for the night in local hotels.

Brown, star of TV comedy series Community and movie (500) Days of Summer, although scared, was also full of praise for Qantas flight and gate crews, describing them as "awesome".