Floyd Wisner, the Chicago-based aviation lawyer leading the class action, told Lawyers Weekly that the case, which targets manufacturers Airbus and Northrup Grumman - the manufacturer of the aeroplane's air data inertial reference unit - is more likely to succeed in its bid to seek both physical and psychological damages in a US court.

"Australia is a little stricter in its law than the US for the recovery of claims for solely psychological injury," he said.

More than 120 passengers on board the 2008 Qantas Flight 72 from Singapore to Perth, including 90 Australians, have now joined the class action - with a two-year statute of limitations regarding the incident due to expire on 7 October.

Floyd said that while some passengers suffered serious physical injuries as a result of the two nose dives, the psychological injuries have caused particular harm for the passengers.

"It's not a matter of just turbulence. Everyone experiences some turbulence on a flight. I would never try to bring a suit against an airline or anybody else for just turbulence," he said.

"The issue is that this plane went into a plunge twice towards the ocean where people thought they were going to die."

US courts also allow for a component of aviation compensation claims known as "pre impact terror", which is the psychological damage a person goes through during an air crash.

"That's a big part of a case in the US, and one that we always include. We have experts who talk about that - what your body and mind goes through.

"I've had cases before where a plane went into a dive because of a mechanical function from 30,000 feet and it takes a while to get to the ground. What the body goes through is very unsettling."

Wisner's firm, Wisner Law Firm, has successfully claimed compensation for the families of victims of numerous major airline disasters over the last 15 years. He said this case is unique in that the two nose dives did not result in death.

Wisner is also involved in a compensation claim surrounding the 2009 AirFrance disaster, which he says shares some "troubling similarities" with the Qantas plunge.

See next week's edition of Lawyers Weekly for more on this story