Argentine pilot in helicopter crash had 'vast experience'
The pilot who flew a helicopter involved in a deadly crash in Argentina on Monday was "vastly experienced", his partner has told the BBC.
Eight French nationals, including three sports stars, and the Argentine pilots died when the two helicopters collided.
Experts are investigating the accident, which happened in good weather in La Rioja province.
The sports stars were taking part in the filming of French TV reality show Dropped.
The partner of pilot Juan Carlos Castillo told the BBC's Wyre Davies that Mr Castillo was a war veteran who had more than three decades of flying experience.
Azucena Aguero said her partner had flown many times with the TV production company producing the show.
She said she had "no idea" why the two helicopters had collided in such ideal conditions near the town of Villa Castelli in northern Argentina.
Video of the accident shows the helicopters flying close to each other in clear conditions, before one appears to fly into the other.
French air investigators will join Argentine experts to probe the causes of the crash, in which Olympic swimmer Camille Muffat, boxer Alexis Vastine and sailor Florence Arthaud died.
French President Francois Hollande said their death was "a cause of immense sadness".
The three sports stars killed
Camille Muffat, 25, won three medals, including gold in the 400m freestyle in the 2012 London Olympics. She retired from competitive swimming in 2014.
Alexis Vastine, 28, won bronze at the 2008 Beijing Olympics in the light-welterweight category. He was narrowly beaten in the quarter-finals of the 2012 Games.
Florence Arthaud, 57, was a hugely accomplished sailor, winning the 1990 Route du Rhum, the prestigious solo Atlantic race. A serious car accident put her in a coma when she was 17.
In the TV show, participants are flown into rough terrain and filmed while they attempt to find food and shelter.
Reports in Argentina said French swimmer Alain Bernard, who was also taking part in Dropped, narrowly escaped the crash after getting off one of the helicopters at the last minute to avoid overloading it.
The five other French nationals killed were said to have worked for Adventure Line Productions (ALP), the company making the programme.
They were named as Laurent Sbasnik, Lucie Mei-Dalby, Volodia Guinard, Brice Guilbert and Edouard Gilles.
The pilot of the second helicopter was identified as Roberto Abate.
Helicopter crashes on location
- 2006: Cameraman Roland Schlotzhauer dies when the helicopter he is in hits power lines and crashes in a field in Iowa during filming of baseball movie The Final Season
- 2011: A helicopter filming for digital television G4's Campus PD reality series crashes into student housing at Indiana University of Pennsylvania, killing cameraman Greg Jacobsen
- 2012: American cinematographer Mike deGruy and Australian TV writer-producer Andrew Wight are killed when their helicopter crashes on takeoff in eastern Australia
- 2013: Three people are killed - pilot David Gibbs, cameraman Darren Rydstrom and cast member Michael Donatelli - when their helicopter crashes in Los Angeles County during the filming of a new reality TV show for the Discovery Channel
The surviving crew and members of the show, which airs on French channel TF1, are staying in Argentina for the time being while the investigation is under way, our correspondent says.
Among them are cyclist Jeannie Longo, former Arsenal footballer Sylvain Wiltord, snowboarder Anne-Flore Marxer and former figure skater Philippe Candelor.
In France, prosecutors have opened a manslaughter investigation - a standard procedure when its nationals die overseas.
Tributes have poured in to the dead stars from France and beyond.
"We are shocked by this sad news," said Thomas Bach, President of the International Olympic Committee.
"The world of sport and the Olympic family have lost three of their key members," he said, calling them champions and role models.
Dame Ellen MacArthur, the British round-the-world yachtswoman, told the BBC she was convinced Florence Arthaud had "inspired many, many people".
British swimmer Rebecca Adlington, who took bronze when Muffat won gold in the 400m freestyle at the London 2012 Olympics, said she was "terribly saddened".
"She was very inspiring, a tough competitor, extremely talented and [a] friendly person." Adlington wrote on her blog.