Heartbreaking final photo moments before deadly helicopter flight

A mother-son embrace, beaming smiles and a fateful ticket for a doomed helicopter flight.

That's Simon Tadros' last permanent memory of his wife, Vanessa, in a photo taken minutes before she and their 10-year-old son, Nicholas, got on board a Sea World Helicopters flight on Monday.

He watched from the ground as the helicopter spent less than a minute in the air before colliding with another chopper and crashing into the ground.

READ MORE: 'I couldn't imagine anyone surviving that': Man tells of chopper terror

Vanessa was killed and Nicholas was still fighting for life in hospital today in what his father described as a "a very serious and critical state".

British couple Ron and Diane Hughes were also killed in the helicopter crash along with the aircraft's pilot Ashley Jenkinson.

Mr Tadros described his wife as "the most loving kind-hearted caring angel".

"She would always put other people first and do anything to make other people happy," he told 9News.

"The love she had for her family and friends is indescribable. She had a beautiful soul, she will be deeply missed."

READ MORE: Tributes to victims at crash site as long investigation begins

The Tadros' neighbour Samuel Gobraiel was just as effusive in his tribute to the 36-year-old.

"She was just the most amazing person," he told 9News.

"She's full of kindness and love and happiness, really.

"She was, that's pretty much it. 

"She's just full of love. Full of love for everyone: her family, her neighbours, her friends."

READ MORE: 'Extremely fortunate' more didn't die in chopper collision: Investigators

Gobraiel described Mrs Tadros as a great mother and wife, calling little Nicholas "the most amazing kid".

Posting on Facebook last night, Mr Tadros thanked everyone who'd come forward to help him.

"I do ask that if everyone can please say a prayer for Nicky, so he can wake up and make a good recovery," he wrote.

"He is in an induced coma on a life support machine to help him breathe. 

"He is in a very serious and critical state. I'm asking for all your prayers to bring my little man back to me."

Investigators are still trying to figure out what caused the two Sea World Helicopters aircraft to collide, seemingly shearing the rotor blade from the chopper that had just taken off, leaving Nicholas, Geelong mother Winne De Silva, and her nine-year-old son, Leon, fighting for life.

Winnie and Leon's conditions improved in hospital but Nicholas remained critical.

Winnie's husband, Neil De Silva, told 9News doctors operated on her broken leg today and finally washed the aviation fuel off her.

"She was able to talk and feeling better this morning but our major concern is Leon and when they wake him up today - that he's okay," he said, with a trembling voice.

Michael James, piloting the other aircraft, somehow wrestled it safely to the ground despite a busted windshield, caved in by the other machine's rotor blade.

He limped from the wreckage suffering shrapnel wounds but with all five of his passengers still alive. 

Elmarie and Riaan Steenberg and Edward and Marle Swart, two New Zealand couples celebrating the new year on the Gold Coast, are recovering and sure to survive, as is a 27-year-old Western Australian woman also on the helicopter that landed.

There was a candlelight vigil at sunset for the four who weren't so lucky.

Rochelle Fajloun, who described Mrs Tadros as a "beloved friend", said her husband had been left "totally shattered".

"Vanessa's beautiful young son Nicholas is critically injured and on life support as he fights for his life in a Gold Coast hospital, with his father by his side," she wrote.

"We are praying for a miracle that our Nicky, (as he is playfully known) can be brought back to his grief stricken father Simon. 

"If by God's grace Nicky survives his catastrophic injuries, he will have an intense and protracted recovery period. Please keep him in your prayers."

A western Sydney church, St John the Beloved Youth in Mt Druitt, also posted a tribute to Mrs Tadros, prompting an outpouring of grief among followers.

Floral tributes at the site were growing this morning as investigators continued what was likely to be a long investigation into the deadly crash. 

Crash site investigators have removed the final pieces of wreckage from the Broadwater on the Gold Coast as they try to piece together how the two Sea World Helicopters aircraft collided mid-flight.