Incident Overview
Upon arriving at the airport, the pilot parked the airplane and reduced the engine power to idle to let two passengers exit. The pilot left the engine running because he planned to conduct another flight. He set the parking brake and exited the airplane.
Sequence of Events
As the pilot exited, he observed the rear seat passenger exit through the rear baggage door and walk away. The front seat passenger then exited through the pilot's door and proceeded to his vehicle. While the pilot was boarding a new passenger for the next flight, he saw one of the previous passengers return to the airplane and walk around the right wing strut.
Aftermath
The pilot then heard a strange sound, and the engine stopped running. He exited the airplane and observed the passenger lying on the ground after being struck by the propeller. Prior to the 10-minute flight, the passengers had each drunk a couple of beers.