What happened
On May 30, 2019, a Jodel D 140 R, registration HB-SFR, was conducting a flight familiarization mission from La Côte airfield (LSGP) toward Lausanne-La Blécherette (LSGL). The aircraft was occupied by a pilot, an instructor, and one passenger. During the takeoff roll on runway 04, the pilot noted that the indicated airspeed was increasing only slightly. Although the aircraft managed to lift off, it failed to climb effectively.
As the aircraft passed the end of the runway, the instructor took control to manage the low-altitude flight. The aircraft was unable to climb or accelerate due to insufficient power. While attempting a left-hand turn to avoid buildings and find a suitable landing area, the aircraft entered a stall at a very low altitude. The wing struck the ground, resulting in the death of the instructor and two serious injuries to the pilot and the passenger. The aircraft was destroyed.
The investigation
SUST examined the aircraft's engine and fuel systems to determine the cause of the power deficiency. Technical inspections of the airframe, fuel circuit, and retractable skis revealed no prior defects. However, investigators discovered a foreign object within the fuel injection regulator that had partially obstructed the injector for cylinder number one. Engine tests on a test bench confirmed that the engine operated normally up to approximately 1800 RPM, suggesting the anomaly was not detectable during the initial high-power takeoff phase.
Findings
- The accident was caused by an undetected lack of engine power during takeoff, which placed the aircraft in a flight regime where it could neither climb nor accelerate.
- The aircraft entered a stall during a low-altitude turn while attempting to maneuver around obstacles.
- A critical contributing factor was the lack of periodic maintenance on the fuel injection regulator, which had not been overhauled since 1986.
- The instructor's decision to attempt a tight turn in a restricted space contributed to the loss of control.