What happened
On May 23, 1964, a student pilot was performing practice landings at Zurich-Kloten Airport using the grass runway parallel to the main concrete runway. During the second landing attempt, the pilot observed a Caravelle, registration YU-AHA, preparing for takeoff on the adjacent runway. As the jet departed at 16:09, the student pilot continued the approach in a Piper Cub J3C, registration HB-OEN.
As the Piper Cub J3C reached an altitude of approximately five to ten meters during the flare, the aircraft suddenly rolled violently to the right into a knife-edge attitude. The pilot momentarily lost control of the aircraft but managed to recover the level attitude after an unintended 90-degree right turn. During the landing roll, the aircraft veered toward the light aircraft parking area, where it collided with a stationary Norécrin II, registration HB-DAG. There were no fatalities or injuries, though the HB-OEN sustained heavy damage to its right wing.
The investigation
Investigators reconstructed the timeline and determined that the wake turbulence from the departing Caravelle reached the flight path of the student pilot approximately 30 seconds after the jet's takeoff. The investigation examined the proximity of the two runways, noting that the configuration of runway 10 places the light aircraft landing area directly in the path of the heavy aircraft departure climb. The commission also reviewed the actions of the flight instructor on the ground and the runway controller, noting that while a landing prohibition signal could have been deployed, the primary cause was the separation distance between the two aircraft.
Findings
- The student pilot approached for landing at too close an interval to the departing commercial jet.
- The Piper Cub J3C entered the wake turbulence generated by the YU-AHA Caravelle during its final approach.
- The proximity of the parallel runways significantly increased the risk of such an encounter.
- The flight instructor and the student pilot both misjudged the safety of the approach, though the commission noted the pilot's recovery actions were appropriate for his training level.