On November 8, 2024, a routine training flight in Estavayer-le-Gibloux, Fribourg, Switzerland, turned into a mid-air emergency when a wasp-like insect blocked a fuel jet, causing severe engine vibrations and power loss. The incident, detailed in a report published on June 2 by the Swiss Transportation Safety Investigation Board (SESE), occurred aboard a two-seater DV20 Katana light aircraft.
Incident Details
The fully qualified pilot and instructor took off from Écuvillens airfield at 3:01 PM after standard safety checks. Just two minutes later, at an altitude of 3,700 feet, the plane began shaking violently. The instructor quickly took control and reduced throttle, temporarily stopping the vibrations. After checking for engine ice, he attempted to increase power again, but the violent shaking and power loss immediately returned.
Unable to maintain stable flight, the crew glided the aircraft back toward the airfield and executed a safe emergency landing. The crew did not radio a Mayday distress call, a step that air safety investigators noted should ideally always be performed.
Cause of the Incident
The SESE investigation revealed that a wasp-like insect had entered a vent line lacking any guard or protective screen. The insect then lodged itself inside the right carburettor, partially blocking the main jet and restricting fuel flow. This caused two of the engine's cylinders to misfire, throwing the engine out of sync and generating the violent vibrations.
Recommendations and Actions
Investigators emphasized that the report aims to prevent future accidents rather than assign blame. They urged regulators and manufacturers to better protect engine ventilation openings. In response, aircraft manufacturer Diamond issued guidance to check vent pipes and install a new clear filter. Engine manufacturer Rotax announced it would update its manuals to highlight the importance of protecting these parts from debris.
