Wife launches legal action in MH370 mystery

The grieving wife of a New Zealander on missing Malaysian Airline flight MH370 has launched legal action against Boeing, believing it was a fault in the plane that caused its crash and disappearance in 2014.

Danica Weeks waved goodbye with her two young children to her 38-year-old husband Paul Weeks on March 8, 2014, as he headed for a flight to take him to work at a Mongolian mine site.

The New Zealander would board Malaysia Airline flight MH370 in Kuala Lumpur for the next leg of the flight to Beijing.

But that airline, along with its 239 passengers, disappeared into thin air and has never been found.

Ms Weeks, who now lives in Cooroy on Queensland's Sunshine Coast after moving from Perth, has her own theories about what happened to the flight and she does not believe it has anything to do with the pilot.

"I've always believed the fault was with the plane, which is why I put a court case out against Boeing in the US - to prove that the Boeing 777s that are still flying are safe," she said.

She was still waiting for a response from Boeing, but Ms Weeks and the families of the MH370 victims have been given renewed hope this week that the mystery of the missing airline could finally be solved.

The Malaysian Government has signed an agreement for private company Ocean Infinity to search for the missing aircraft on a 'no cure, no fee' basis.

Malaysia has agreed to pay up to $US70 million if Ocean Infinity can find the main wreckage within 90 days of embarking on this new search in the Southern Indian Ocean.

Ms Weeks said she had never been able to say goodbye to her husband and it still felt like yesterday that she was waving goodbye to him.

"The journey been surreal - it feels like yesterday to us and it has nearly been four years," she said.

Her son, Jack, was only 11 months old when their father disappeared and is now getting ready to start prep at school.

His brother Lincoln, now seven, helps explain to Jack what their father was like.

"He tells him stories about their dad," Ms Weeks said.

She has no plans to hold a memorial service for her husband until there are answers.

"We don't know where, how, or why, and after nearly four years, it is just bizarre," she said.

"I haven't had a memorial - I think I would be kidding myself if I had one.

"We are still without a death certificate - I don't want one - I want him to be found."

She said the whole situation was very difficult.

"I am dealing with the emotion and the physical reality he is not here - it is really tough," she said.

"It doesn't get easier, it actually gets worse - we are getting tired, we want the answers, we have been through so many searches, such hope with no fruition, it weights down on me.

"I'm lucky Paul gifted me with two beautiful boys - that keeps me going."