What happened
On 18 October 2011, a Eurocopter EC120B helicopter, operating for Heli and Co S.A., was conducting a low-level pipeline surveillance mission. After completing the survey tasks, the aircraft was returning to its base at Spa airfield. As the helicopter reached the Soumagne area, it encountered rapidly deteriorating weather, leading to an unintentional entry into Instrument Meteorological Conditions (IMC).
While attempting to climb to avoid high-voltage lines, the aircraft entered IMC. The pilot attempted a corrective turn to return to known conditions, but the maneuver resulted in a loss of control. The helicopter crashed into trees in a residential garden, causing the death of both occupants.
The investigation
Investigators from AAIU(Be) examined the wreckage and analyzed flight data from the aircraft's GPS and VEMD. The investigation confirmed that the helicopter was airworthy prior to the accident and that no mechanical failures in the flight controls or transmission occurred before impact. Analysis of the engine and rotor components showed that the engine was still delivering significant power at the moment of impact.
Data from the GPS and radar traces revealed that the aircraft's flight path became unstable during the turn in low visibility. The investigation also reviewed the pilot's background, noting that while the pilot was qualified, their specific experience with the EC120 model was limited compared to their experience with Robinson R22 and R44 helicopters, which feature different rotor rotation and tail rotor configurations.