What happened
On August 4, 2009, at 19:08, an EV-97 Eurostar (registration OH-U507) was conducting a training flight at Kauhava aerodrome when it crashed into the ground. The flight was intended to simulate an engine failure following takeoff, specifically practicing a maneuver to turn back and land on the runway in the opposite direction of the initial departure.
After reaching an altitude of approximately 350 feet (107 m) AGL, the pilot set the engine to idle to initiate the simulated failure. The pilot then began a descending right-hand turn into a headwind. During this maneuver, the aircraft lost significant altitude and airspeed. The student flight instructor, who was operating the aircraft, lost control as the airspeed dropped to the stall threshold. The aircraft abruptly rolled to the right and entered a steep dive, impacting the ground in a nearly vertical attitude. Both occupants of the aircraft sustained fatal injuries and died instantly.
The investigation
The investigation examined the flight profiles, the training syllabus, and the regulatory environment for microlight flight instruction. Investigators looked into why the specific maneuver—turning back to the runway at low altitude—was being practiced, as it is considered a high-risk maneuver. The inquiry also reviewed the competence of the student flight instructor and the interpretation of aviation regulation PEL M2-71 regarding instructor-student rights. Additionally, the investigation looked into the aircraft's weight, noting that the aircraft exceeded its maximum takeoff mass by 32 kg.
Findings
- The immediate cause of the accident was inadequate monitoring of flight parameters during the technically demanding turn-back maneuver, which led to an aerodynamic stall.
- The low altitude at which the maneuver was performed left no margin for error or recovery from the stall.
- The student flight instructor lacked the necessary experience and proficiency to safely execute and instruct this specific maneuver.
- A prevailing culture in some microlight training organizations encouraged practicing engine failure simulations by turning back at very low altitudes, despite a lack of formal guidance in the training syllabus.
- There were inconsistent interpretations of instructor-student rights among different flight clubs.
- The aircraft was operating above its maximum allowable takeoff weight.