GENEVA - A plane crash at a Swiss summer camp on Friday killed two 14-year-old campers and the pilot, while leaving a third teenager seriously injured, police said. The ride in the single-engine plane was organised at the Aero-Club of Switzerland camp in the canton of Graubunden, police said, adding that an investigation had been opened into the cause of the crash in the mountainous region. “My world has collapsed”, Yves Burkhardt of the Aero-Club told reporters.