US daredevil Dean Potter 'pushed the envelope'
Climber Doug Robinson has paid tribute to Dean Potter, one of America's best known rock climbers and extreme athletes, who has been killed while attempting a flying stunt in California.
The 43-year-old died while attempting a wingsuit flight from the 7,500 ft (2,286m) Taft Point promontory in Yosemite National Park, a park spokesman said.
Mr Robinson spoke to Newsday on the BBC World Service radio.
18 May 2015