What happened
On March 24, 2000, a Robinson R22 Mariner, registration OH-HWC, was conducting a private flight training mission near Vammala, Finland. The pilot had departed from Tampere-Pirkkalan airport for a two-hour training flight intended to practice hovering maneuvers around the ruins of an old agricultural building in Liuholan village.
While performing approximately 1.5 circuits around the landmark at an altitude of roughly 10 meters, the pilot encountered gusty and shifting winds. As the helicopter transitioned from a tailwind hover to a left-side crosswind hover at the northern end of the ruins, the aircraft began to sink. The pilot failed to increase power sufficiently to compensate for the wind conditions. The aircraft descended to an altitude of approximately one meter, where the presence of uniform white snow made height estimation difficult. The helicopter struck the ground, slid approximately five meters laterally, and eventually overturned onto its right side. The aircraft sustained heavy damage, including a broken rotor blade and structural damage to the airframe, but the pilot escaped without injury.
The investigation
The investigation examined the aircraft's technical condition, the pilot's experience, and the environmental factors at the time of the accident. Investigators reviewed the flight plan, weather data from local stations, and the pilot's training records. A technical inspection of OH-HWC at Tampere-Pirkkalan airport revealed significant damage to the main rotor blades, the mast, and the cockpit glazing. Notably, the investigation also identified a defect in the left-side foot pedal locking mechanism, where a bent spring prevented the pedal from being properly secured.
Findings
- The primary cause of the accident was the pilot's failure to apply sufficient power to prevent the helicopter from descending during the maneuver.
- The pilot's limited flight experience, totaling only 87 hours and 35 minutes (with only 21 hours and 25 minutes on this specific type), contributed to the inability to react effectively to the changing wind.
- Gusty, variable winds and the difficulty of judging altitude over a snow-covered field acted as contributing factors.
- A mechanical defect was discovered in the pedal locking mechanism, which could potentially cause the pedals to interfere with one another if they were to move out of position.