What happened
On September 29, 1962, at approximately 16:35 CEST, a Piper J3 (L-4), registration HB-OCH, was positioned on a grass taxiway at Zurich-Kloten Airport. The aircraft, operated by the Motorfluggruppe Zürich, was being used for a dual-control training flight. The aircraft had taxied from Hangar Nord and was positioned near the windsock, a standard location for engine warm-up.
At the same time, a Canadair CL-44 cargo aircraft, operated by Seaboard World Airlines, was being marshaled by a ground controller along taxiway 1 toward a parking stand. As the pilot of the CL-44 increased power to maneuver the large aircraft, the resulting propeller blast reached the stationary Piper. The force of the jet/propeller wash caused the Piper's right wing to lift. In an attempt to steer away from the danger by applying left power, the pilot inadvertently caused the tail to lift as well. This led to the aircraft flipping over its engine and coming to rest on its back.
The investigation
The investigation examined the movements of both aircraft and the ground operations at the time of the incident. It was established that the occupants of the Piper J3 (L-4) were unable to hear the approaching freighter due to engine noise within their own cockpit. Furthermore, the investigation noted that the pilot of the large freighter would have had significant difficulty monitoring objects behind the aircraft during that phase of taxiing. The investigation also looked into the actions of the ground controller, who was directing the freighter past nearby obstacles toward the parking area.
Findings
- The primary cause of the accident was the impact of the propeller blast from the passing large aircraft on the stationary training aircraft.
- The occupants of the Piper were unaware of the approaching CL-44 due to high ambient noise levels.
- The pilot of the large aircraft was unlikely to have detected the stationary Piper while maneuvering.
- The physical layout of the airport taxiways contributed to the proximity of the two aircraft.
Damage
The accident resulted in no fatalities, though the pilot sustained a minor head contusion. The aircraft sustained significant damage, including a severely twisted right wing, broken propeller blades, and structural deformation to the vertical stabilizer and engine cowling.