Berlin: A 14-year-old boy was at the controls of a small plane that crashed in the Alps in 2017, killing him and two other people, Swiss investigators say.

The Piper PA-28 aircraft crashed in southeast Switzerland in August 2017.

The plane's pilot and another 14-year-old boy were also killed, and a 17-year- old girl was seriously injured.

The Swiss Transportation Safety Investigation Board said in a report on Friday the pilot had chosen a risky flight course.

In addition, it said that "the pilot's risky decision to hand the controls to the passenger (was) a direct contributing factor to the accident".

The flight was part of a flying club's annual summer camp for teenagers.

AP