What happened
On August 11, 1977, a Cessna 150 (registration HB-CSF) departed Altenrhein for a private flight around Lake Constance. After completing the flight, the pilot returned to the airfield at approximately 10:49 AM. While taxiing from runway 28 toward the parking stands, the pilot encountered difficulty locating the correct parking spot due to tall grass obscuring the ground markings.
To assist with positioning, the pilot requested that the passenger, who was a first-time flyer, act as a ground guide using hand signals. The passenger exited the aircraft while the engine was still running. After initially positioning herself approximately 10 meters in front of the aircraft, the passenger moved toward the right cabin door to provide further signals and attempt to read the registration on the parking plate. As the pilot taxied forward, the passenger stepped backward into the propeller arc. Although the pilot recognized the danger and attempted to shut down the engine, the propeller struck the passenger, resulting in one serious injury.
The investigation
The investigation established that the pilot held a valid private pilot license and was medically fit for the operation. The aircraft was properly documented and airworthy. The investigation noted that the parking stands used metal plates embedded in the grass to identify specific slots, but high grass significantly obstructed visibility of these markings.
Investigators found that while the pilot had explained the hand signals, the passenger—unfamiliar with flight operations—did not recall receiving specific safety warnings regarding the propeller. Furthermore, the investigation noted that the pilot's visibility of the passenger from the cockpit was good, yet the engine remained running during the passenger's movement around the aircraft.
Findings
- The pilot assigned a ground guiding task to a passenger who lacked familiarity with airfield operations and the inherent risks of active aircraft.
- The pilot exhibited unwise behavior by allowing a passenger to walk near the aircraft while the engine was running.
- The pilot failed to immediately shut down the engine when the passenger approached the aircraft's side.
- The necessity of precise parking was secondary to safety, as the aircraft could have been repositioned manually after the engine was stopped.