At an air show and picnic in the Polish city of Plock, stunt pilot Marek Szufa lost control of his plane and crashed into the Vistula River. Szufa, 57, was killed in the crash. He spoke to Polish radio before the incident saying that the maneuvers he would be executing required special permission from the Civil Aviation Office because of their complexity and high level of risk.

It is unknown whether the crash was caused by mechanical failure or pilot error, although some witnesses report seeing smoke belching from the aircraft’s engine compartment seconds before the crash.

Watch the video, from the Associated Press, below: