THE de facto partner of Daniel Leverton, the RAAF serviceman whose young daughters were left out of the bulk of his estate, has broken her silence.

Kirsty Lea Lewis, an RAAF servicewoman who worked with Mr Leverton and was his legal de facto at the time of his death, has defended her decision to pocket the bulk of the $451,500 worth of retirement savings and life insurance held by his superannuation fund — leaving his young children, born to a previous partner, with less than one-quarter of his estate.

Ms Lewis walked away with $352,170 after the mother of Mr Leverton’s children unsuccessfully appealed a decision of Military Super to award Ms Lewis the lion’s share, news.com.au revealed on Monday, prompting the serviceman’s father Geoff Leverton to slam the decision as a “travesty of justice”.

But the young woman who had lived with the airman for the nine months leading up to his death has hit out at the family’s claims the union was nothing more than a “casual” tryst, telling news.com.au through her lawyers that the pair had “a meaningful relationship”.

Mr Leverton died suddenly in April 2015 while on a surfing trip with friends, after returning from a humanitarian mission in Vanuatu.

The airman’s family has maintained that he had only signed a statutory declaration making Ms Lewis his de facto in order to avoid being posted interstate, thousands of kilometres away from his beloved daughters in Queensland.

Ms Lewis’ solicitor said in a statement that she had attempted to settle the dispute with the girls’ mother, Angela Watson, in July 2015.

“When the Military Super decision was originally handed down, our client made an offer to the mother of Mr Leverton’s children, via her solicitor, to gift a significant sum to the children from the benefit she was due to receive,” the statement said.

“This offer ... was never accepted by the mother of the children.”

Military Super did not allow its members to nominate beneficiaries, she said, and had complete discretion over who would be paid out in the event of a serviceman’s death.

“It was completely beyond our client’s control as to the decision that was reached by Military Super,” she said.

Geoff Leverton said that Ms Lewis had offered $100,000 to each of the girls, which he described as “very much inadequate”.

That amount would have left Ms Lewis with $251,500, or 56 per cent. “The worst case scenario should have been a three-way split,” Mr Leverton argued.

Ms Watson said she could not countenance a settlement that gave Ms Lewis more than her daughters, who had a close relationship with their dad.

“All I wanted was for the girls to be considered fairly, which they haven’t been,” she said.

“They’ve still got their whole lives ahead of them. No amount of money will bring back their Daddy, but it can certainly help make their futures a bit easier.

“As their mum, I’ve tried to fight what they deserve. Any loving mother would do the same thing in this situation.”

Ms Lewis also disputed the length of her relationship with Mr Leverton, but declined to give further details.

His former partner Ms Watson said the pair had separated in December 2012, but continued living together until April 2014.

“I knew she was ‘hanging around’ on and off during 2014,” she said of Ms Lewis.

“He tried to break up with her in December 2014 while we were all down in Coffs Harbour for Christmas.”

But, the Commonwealth Superannuation Corporation found, he was living in a domestic partnership with Ms Lewis when he died.

The airman’s last will and testament stated his wishes that his estate should go to Ms Watson, who was named as his executor and sole beneficiary, the family maintains, and declined to change it despite being invited to do so by the RAAF before his last overseas posting.

But, the Commonwealth Superannuation Corporation found, he was living in a domestic partnership with Ms Lewis when he died.

dana.mccauley@news.com.au