What happened
On September 14, 2002, at approximately 18:00 local time, an Aerospatiale SA-316B Alouette III, registration EC-EEC, was performing firefighting operations in Paradela, A Coruña. The helicopter, operated by Helicsa-Helicópteros, S.A., had recently refueled in Castromaior and was carrying a crew of six firefighters.
The aircraft was operating from an unprepared landing site in a mountainous area, specifically a small clearing. During the takeoff maneuver from a hover, the pilot encountered significant environmental challenges, including 20-knot winds from 070° and nearby thunderstorm activity. As the pilot transitioned from a hover to forward flight at an altitude of approximately 6 meters, the aircraft experienced a sudden and sharp upward movement of the rear fuselage, leading to a pronounced nose-down pitch.
In an attempt to correct this attitude, the pilot applied aft cyclic. However, the main rotor assembly reacted more rapidly than the fuselage, causing the rotor blades to strike the tail cone. The impact caused severe vibrations and noise. Due to a steep 250-meter drop immediately ahead of the takeoff site, the pilot was unable to land immediately and instead performed an emergency landing in a meadow approximately 400 meters away. The aircraft sustained significant damage to the main rotor blades, the tail boom, and the vertical stabilizer, but the pilot and all six passengers escaped without injury.
The investigation
The CIAIAC investigation examined the pilot's experience, the aircraft's maintenance history, and the environmental conditions at the time of the incident. The investigation confirmed that the pilot held a valid commercial helicopter license and was experienced in emergency and firefighting operations. The aircraft's airworthiness certificate was valid, and maintenance records showed the helicopter had been maintained according to the approved program.
Investigators analyzed the structural damage to EC-EEC, noting that the deformation of the rotor blades and the damage to the tail boom and vertical stabilizer were consistent with a rotor strike. The investigation also assessed the meteorological conditions, noting the presence of cumulonimbus clouds and gusty winds characteristic of mountainous terrain near approaching storms.
Findings
- The takeoff was performed from an unprepared landing site in a mountainous region.
- The aircraft was operating in unstable meteorological conditions, characterized by high-intensity gusty winds and the proximity of a thunderstorm.
- The turbulence caused by the combination of mountainous terrain and approaching storm activity triggered the sudden pitch-down movement.
- A discrepancy in the reaction timing between the main rotor assembly and the fuselage led to the blades impacting the tail cone.