History of the Flight
On Thursday, 21 July 1983 at approximately 1835 hours local time, a pilot took off from Porrentruy airfield in a Piper L4 (Piper J3C), registration HB-OXD. The pilot's wife was seated in the front seat; the pilot occupied the rear seat. After a local flight of about half an hour, the pilot landed again at Porrentruy on runway 07, intending to change passengers and conduct another flight.
Due to a high concentration of parked aircraft, the pilot decided to stop near the signal area. Because the aircraft was not equipped with a starter and no person was available to hand-prop the engine, the pilot chose to perform the passenger change with the engine running at idle. The aircraft's nose was oriented at 350°. The pilot warned the passenger about the danger posed by the propeller when she left the cockpit.
Injuries
The passenger exited the aircraft and, while moving away, suddenly turned to wave goodbye to her husband. As she turned, her left arm was caught by the propeller, causing her to fall. In the same motion, the propeller struck her head and back. The passenger was seriously injured.
Probable Cause
The accident occurred because the engine was not shut down during a passenger change from the front seat and the exiting passenger was struck by the propeller.