What happened
On May 9, 2024, at approximately 15:20 local time, a Robinson R44 Raven II helicopter was conducting a local visual flight from a private estate in Vilanova de l’Aguda, Lleida. The aircraft, which bore the Swiss registration HB-ZII on its fuselage, was being operated by its two owners for the purpose of familiarization and practice.
After approximately 20 minutes of flight, the pilot experienced significant vibrations in the main rotor mast. In an attempt to perform an emergency landing via autorotation, the pilot was unable to complete the maneuver because the main rotor lost lift due to low RPM. The helicopter struck a cereal field with high vertical velocity. Upon impact, the aircraft slid five meters, rotated 180 degrees, and overturned on its right side. There was no post-crash fire. Both the pilot and the passenger sustained two serious injuries.
The investigation
The investigation established that the aircraft was not in an airworthy condition. Although the fuselage displayed the registration HB-ZII, the Swiss registration authorities had decommissioned the aircraft in August 2023. Furthermore, the owners had purchased the aircraft specifically as a non-flight-worthy static mock-up for pedagogical use.
The investigation found that the owners had transported the helicopter to Spain in September 2023 but had not initiated the re-registration process with Spanish authorities, nor had they performed the necessary maintenance to return the aircraft to a flight-worthy state. The investigation also noted that the pilot failed to ensure the aircraft met the necessary operational limitations regarding airworthiness and registration.
Findings
- The Robinson R44 Raven II was being operated without a valid Certificate of Airworthiness.
- The aircraft had exceeded its service life and was intended for ground-based instructional use only.
- The primary cause of the accident was the loss of main rotor lift due to low RPM during flight maneuvers.
- The impact was characterized by high vertical speed and low rotor revolutions.
- The pilot failed to comply with regulatory responsibilities regarding the verification of an aircraft's airworthiness and registration prior to flight.