Investigating judge Daniel Herrera gave the green light for Olympic champion swimmer Alain Bernard, figure skater Philippe Candeloro, cycling legend Jeannie Longo and snowboarder Anne-Flore Marxer to return after questioning them about Monday's crash in Argentina's remote northwest.

The final participant on the show, former international and Arsenal footballer Sylvain Wiltord, had already returned to France before the crash.

"I spoke to the people I needed to speak and gathered their testimony and I have decided to allow all members of the production and participants to return to their country," Herrera told AFP.

There were no survivors in Monday's deadly collision between two helicopters that were filming the reality series "Dropped" in the rugged terrain of La Rioja province.

The crash killed Olympic champion swimmer Camille Muffat, renowned yachtswoman Florence Arthaud and Olympic boxer Alexis Vastine, as well as five French television crew members and two Argentine pilots.

An agent for one of the sports stars spoken to Thursday said the entire group would take a Friday night flight to France, arriving in Paris Saturday morning — a plan confirmed by a source close to the case.

A team of officers from France's gendarmerie police force was meanwhile en route to join their Argentine counterparts to comb through the charred wreckage of the helicopters and work to identify the bodies.

Investigators from France's air accident investigation authority, the BEA, as well as helicopter manufacturer Airbus Helicopters and engine maker Turbomeca, are already working at the scene, where they have begun dismantling the aircraft, looking for clues.

Argentine forensic experts are waiting for their French counterparts to arrive to begin identifying the victims' remains, a local coroner said.

Investigators will have to rely on dental records or DNA tests to identify the badly burned bodies, officials say.

"Dropped," which was to air on French channel TF1 but was immediately canceled after the crash, featured sports stars who were taken blindfolded into rugged environments and given 72 hours to get to a place where they could charge a mobile phone.

Initial investigations indicate the crash was caused by human error, officials say.