Federal politicians have demanded South African authorities take action against an aircraft maintenance company at the centre of a crash that killed three West Australians 8 1/2 years ago.
In an unusual move, WA Labor frontbencher Gary Gray and WA Liberal MP Judi Moylan have criticised the South African investigation into the company, warning more people could die if safety standards were not enforced.
Justine Watters and husband Matthew, both 26, and Matthew's mother Shirley, 58, all from Darlington, died in a light plane crash near Victoria Falls on September 9, 2004.
Also killed were their friends from Britain, Justin and Rebecca Ward, and Canadian pilot Mike Channer.
The group was on a two-week holiday in Zambia and on the way to view Victoria Falls when the propeller of the Cessna 210 fell off while the aircraft was at 8000ft.
The pilot made an attempt to glide the aircraft to a safe landing, but oil splashed across the window and obscured his view and the plane crashed into trees, killing all aboard.
The plane was maintained in South Africa by Nelair and local air safety authorities promised the company would lose its licence and be barred from trading.
But Nelair is still operating and is thought to be one of the country's biggest maintenance operators.
It has been linked to at least two other major crashes since - with one incident also involving a propeller coming off a plane.
Mrs Watters' father Sam Morton has continued to pursue Nelair.
"This is about the natural progression of the truth," Mr Morton said. "I have got no axe to grind. It could be that there was no negligence here and it was just a tragic accident."
The South African investigation has been marred by delays and the mysterious loss of key files and evidence.
Mr Gray and Ms Moylan spoke in Parliament this week expressing their frustration at the lack of action against the company.
The South African High Commission said its Government was disappointed evidence related to the case had gone missing.